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Akhgarjand C, Tavakoli A, Samavat S, Bagheri A, Anoushirvani A, Mirzababaei A, Amini MR, Ghorbi MD, Valisoltani N, Mansour A, Sajjadi-Jazi SM, Ansar H, Rezvani H. The effect of conjugated linoleic acid supplementation in comparison with omega-6 and omega-9 on lipid profile: a graded, dose-response systematic review and meta-analysis of randomized controlled trials. Front Nutr 2024; 11:1336889. [PMID: 38567248 PMCID: PMC10985181 DOI: 10.3389/fnut.2024.1336889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 02/05/2024] [Indexed: 04/04/2024] Open
Abstract
Conjugated linoleic acid (CLA) is a geometrical isomer of linoleic acid, which has anti-inflammatory, anti-diabetic, anti-cancer, and anti-obesity properties. However, the studies reported inconstant results about the CLA-related effects on lipid profiles. As a result, meta-analysis and systematic review were performed to survey the CLA supplementation-related effect on lipid profile including high-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol (TC), and triglycerides (TG). To identify the relevant research, a systematic comprehensive search was initiated on the medical databases such as Scopus and PubMed/Medline until December 2022. The overall effect size was estimated by weighted mean difference (WMD) and 95% confidence interval (CI) in a random effect meta-analysis. In the final quantitative analysis, the meta-analysis considered 35 randomized controlled trials (RCTs) with 1,476 participants (707 controls and 769 cases). The pooled results demonstrated that CLA supplementation, compared with olive oil, significantly increased serum TG levels (WMD: 0.05 mmol/L; 95% CI: 0.01 to 0.1; p = 0.04; I2 = 0.0%, p = 0.91). With regard to TC level, CLA supplementation compared with placebo significantly reduced TC concentrations (WMD: -0.08 mmol/L; 95% CI: -0.14 to -0.02; p < 0.001; I2 = 82.4%). Moreover, the non-linear dose-response analysis indicated a decreasing trend of TC serum level from the 15th week of CLA supplementation compared with olive oil (Pnon-linearity = 0.01). The present meta-analysis and systematic review of 35 RCTs showed that the CLA intervention was able to raise the level of TG in comparison to olive oil; however, it can decrease TC level compared with placebo and olive oil.
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Affiliation(s)
- Camellia Akhgarjand
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Aryan Tavakoli
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Simin Samavat
- Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Bagheri
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Aliarash Anoushirvani
- Hemato-Oncology Ward, Firoozgar Hospital, Iran University of Medical Science, Tehran, Iran
| | - Atieh Mirzababaei
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Amini
- Student Research Committee, Department of Clinical Nutrition and Dietetics, Faculty of Nutrition Sciences and Food Technology, National Nutrition & Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahmoud Dehghani Ghorbi
- Hemato-Oncology Ward, Imam Hossein Hospital, Shahid Beheshti University of Medical Science, Tehran, Iran
| | - Neda Valisoltani
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Asieh Mansour
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Sayed Mahmoud Sajjadi-Jazi
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Hastimansooreh Ansar
- Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamid Rezvani
- Hemato-Oncology Ward, Taleghani Hospital, Shahid Beheshti University of Medical Science, Tehran, Iran
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Asbaghi O, Shimi G, Hosseini Oskouie F, Naseri K, Bagheri R, Ashtary-Larky D, Nordvall M, Rastgoo S, Zamani M, Wong A. The effects of conjugated linoleic acid supplementation on anthropometrics and body composition indices in adults: a systematic review and dose-response meta-analysis. Br J Nutr 2024; 131:406-428. [PMID: 37671495 DOI: 10.1017/s0007114523001861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
Prior meta-analytic investigations over a decade ago rather inconclusively indicated that conjugated linoleic acid (CLA) supplementation could improve anthropometric and body composition indices in the general adult population. More recent investigations have emerged, and an up-to-date systematic review and meta-analysis on this topic must be improved. Therefore, this investigation provides a comprehensive systematic review and meta-analysis of randomised controlled trials (RCT) on the impact of CLA supplementation on anthropometric and body composition (body mass (BM), BMI, waist circumference (WC), fat mass (FM), body fat percentage (BFP) and fat-free mass (FFM)) markers in adults. Online databases search, including PubMed, Scopus, the Cochrane Library and Web of Science up to March 2022, were utilised to retrieve RCT examining the effect of CLA supplementation on anthropometric and body composition markers in adults. Meta-analysis was carried out using a random-effects model. The I2 index was used as an index of statistical heterogeneity of RCT. Among the initial 8351 studies identified from electronic databases search, seventy RCT with ninety-six effect sizes involving 4159 participants were included for data analyses. The results of random-effects modelling demonstrated that CLA supplementation significantly reduced BM (weighted mean difference (WMD): -0·35, 95 % CI (-0·54, -0·15), P < 0·001), BMI (WMD: -0·15, 95 % CI (-0·24, -0·06), P = 0·001), WC (WMD: -0·62, 95% CI (-1·04, -0·20), P = 0·004), FM (WMD: -0·44, 95 % CI (-0·66, -0·23), P < 0·001), BFP (WMD: -0·77 %, 95 % CI (-1·09, -0·45), P < 0·001) and increased FFM (WMD: 0·27, 95 % CI (0·09, 0·45), P = 0·003). The high-quality subgroup showed that CLA supplementation fails to change FM and BFP. However, according to high-quality studies, CLA intake resulted in small but significant increases in FFM and decreases in BM and BMI. This meta-analysis study suggests that CLA supplementation may result in a small but significant improvement in anthropometric and body composition markers in an adult population. However, data from high-quality studies failed to show CLA's body fat-lowering properties. Moreover, it should be noted that the weight-loss properties of CLA were small and may not reach clinical importance.
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Affiliation(s)
- Omid Asbaghi
- Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ghazaleh Shimi
- Department of Cellular and Molecular Nutrition, Faculty of Nutrition Science and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Hosseini Oskouie
- Department of Clinical Nutrition and Dietetics, Faculty of Nutrition and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Kaveh Naseri
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Reza Bagheri
- Department of Exercise Physiology, University of Isfahan, Isfahan, Iran
| | - Damoon Ashtary-Larky
- Nutrition and Metabolic Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Michael Nordvall
- Department of Health and Human Performance, Marymount University, Arlington, VA, USA
| | - Samira Rastgoo
- Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Cellular and Molecular Nutrition, Faculty of Nutrition Science and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Zamani
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Alexei Wong
- Department of Health and Human Performance, Marymount University, Arlington, VA, USA
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Putera HD, Doewes RI, Shalaby MN, Ramírez-Coronel AA, Clayton ZS, Abdelbasset WK, Murtazaev SS, Jalil AT, Rahimi P, Nattagh-Eshtivani E, Malekahmadi M, Pahlavani N. The effect of conjugated linoleic acids on inflammation, oxidative stress, body composition and physical performance: a comprehensive review of putative molecular mechanisms. Nutr Metab (Lond) 2023; 20:35. [PMID: 37644566 PMCID: PMC10466845 DOI: 10.1186/s12986-023-00758-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023] Open
Abstract
Conjugated linoleic acids (CLAs) are polyunsaturated fatty acids primarily found in dairy products and ruminant animal products such as beef, lamb, and butter. Supplementation of CLAs has recently become popular among athletes due to the variety of health-promoting effects, including improvements in physical performance. Preclinical and some clinical studies have shown that CLAs can reduce inflammation and oxidative stress and favorably modulate body composition and physical performance; however, the results of previously published clinical trials are mixed. Here, we performed a comprehensive review of previously published clinical trials that assessed the role of CLAs in modulating inflammation, oxidative stress, body composition, and select indices of physical performance, emphasizing the molecular mechanisms governing these changes. The findings of our review demonstrate that the effect of supplementation with CLAs on inflammation and oxidative stress is controversial, but this supplement can decrease body fat mass and increase physical performance. Future well-designed randomized clinical trials are warranted to determine the effectiveness of (1) specific doses of CLAs; (2) different dosing durations of CLAs; (3) various CLA isomers, and the exact molecular mechanisms by which CLAs positively influence oxidative stress, inflammation, body composition, and physical performance.
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Affiliation(s)
- Husna Dharma Putera
- Department of Surgery, Faculty of Medicine, Lambung Mangkurat University, Banjarmasin, South Kalimantan, Indonesia
| | - Rumi Iqbal Doewes
- Faculty of Sport, Universitas Sebelas Maret, Jl. Ir. Sutami, 36A, Kentingan, Surakarta, Indonesia
| | - Mohammed Nader Shalaby
- Biological Sciences and Sports Health Department, Faculty of Physical Education, Suez Canal University, Ismailia, Egypt
| | - Andrés Alexis Ramírez-Coronel
- Azogues Campus Nursing Career, Health and Behavior Research Group (HBR), Psychometry and Ethology Laboratory, Catholic University of Cuenca, Azogues, Ecuador
| | - Zachary S Clayton
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Walid Kamal Abdelbasset
- Department of Health and Rehabilitation Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdulaziz University, Al Kharj, Saudi Arabia
- Department of Physical Therapy, Kasr Al-Aini Hospital, Cairo University, Giza, Egypt
| | - Saidmurodkhon S Murtazaev
- Department of Therapeutic Pediatric Dentistry, Dean of the Faculty of International Education, Tashkent State Dental Institute, Tashkent, Uzbekistan
- Department of Scientific Affairs, Samarkand State Medical University, Amir Temur Street 18, Samarkand, Uzbekistan
| | - Abduladheem Turki Jalil
- Medical Laboratories Techniques Department, Al-Mustaqbal University College, Hilla, Babylon, 51001, Iraq
| | - Pegah Rahimi
- Department of Clinical Pharmacy, Faculty of Pharmacy, Kerman University of Medical Sciences, Kerman, Iran
| | - Elyas Nattagh-Eshtivani
- Social Development and Health Promotion Research Center, Gonabad University of Medical Sciences, Gonabad, Iran
| | - Mahsa Malekahmadi
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Naseh Pahlavani
- Health Sciences Research Center, Torbat Heydariyeh University of Medical Sciences, Torbat-e Heydariyeh, Iran.
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Rastgoo S, Shimi G, Shiraseb F, Karbasi A, Ashtary-Larky D, Yousefi M, Golalipour E, Asbaghi O, Zamani M. The effects of conjugated linoleic acid supplementation on inflammatory cytokines and adipokines in adults: A GRADE-assessed systematic review and dose-response meta-analysis. Front Immunol 2023; 14:1092077. [PMID: 36911696 PMCID: PMC9992184 DOI: 10.3389/fimmu.2023.1092077] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 02/02/2023] [Indexed: 02/25/2023] Open
Abstract
Background and aims Many studies have investigated the effect of conjugated linoleic acid (CLA) supplementation on inflammatory cytokines and adipokines. However, the results of these studies are not consistent. Therefore, this systematic review and meta-analysis were designed to comprehensively evaluate the effect of CLA supplementation on inflammatory cytokines and adipokines. Methods Randomized controlled trials (RCTs) examining the effects of CLA supplementation on C-reactive protein (CRP), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), adiponectin, and leptin, published up to March 2022, were identified through PubMed, SCOPUS, and ISI Web of Science databases. A random-effects model was used to calculate weighted mean differences (WMDs) with 95% confidence intervals (CI) for 42 studies that included 1,109 participants. Results Findings from 42 studies with 58 arms indicated that CLA supplementation significantly decreased IL-6 and TNF-α levels and also slightly increased CRP levels. However, adiponectin and leptin levels did not change after CLA supplementation. A subgroup analysis found that CLA supplementation reduced adiponectin and leptin in women. Conclusion Our results demonstrated that CLA supplementation increased CRP levels and decreased TNF-α and IL-6 levels. Therefore, it seems that CLA can have both proinflammatory and anti-inflammatory roles. Systematic review registration https://www.crd.york.ac.uk/prospero/, identifier (CRD42022331110).
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Affiliation(s)
- Samira Rastgoo
- Department of Cellular and Molecular Nutrition, Faculty of Nutrition Science and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ghazaleh Shimi
- Department of Cellular and Molecular Nutrition, Faculty of Nutrition Science and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Farideh Shiraseb
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Ashkan Karbasi
- Department of Clinical Biochemistry, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Damoon Ashtary-Larky
- Nutrition and Metabolic Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohsen Yousefi
- Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elnaz Golalipour
- Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Omid Asbaghi
- Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Zamani
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
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The effects of conjugated linoleic acid supplementation on liver function enzymes and malondialdehyde in adults: A GRADE-assessed systematic review and dose-response meta-analysis. Pharmacol Res 2022; 186:106518. [DOI: 10.1016/j.phrs.2022.106518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/14/2022] [Accepted: 10/14/2022] [Indexed: 11/06/2022]
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Asbaghi O, Ashtary-larky D, Naseri K, Saadati S, Zamani M, Rezaei Kelishadi M, Nadery M, Doaei S, Haghighat N. The effects of conjugated linoleic acid supplementation on lipid profile in adults: A systematic review and dose-response meta-analysis. Front Nutr 2022; 9:953012. [PMID: 36438733 PMCID: PMC9682566 DOI: 10.3389/fnut.2022.953012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/28/2022] [Indexed: 09/11/2023] Open
Abstract
Background The findings of trials investigating the effect of conjugated linoleic acid (CLA) administration on lipid profile are controversial. This meta-analysis of randomized controlled trials (RCTs) was performed to explore the effects of CLA supplementation on lipid profile. Methods Two authors independently searched electronic databases including PubMed, Web of Science, and Scopus until March 2022, in order to find relevant RCTs. The random effects model was used to evaluate the mean and standard deviation. Results In total, 56 RCTs with 73 effect sizes met the inclusion criteria and were eligible for the meta-analysis. CLA supplementation significantly alter triglycerides (TG) (WMD: 1.76; 95% CI: -1.65, 5.19), total cholesterols (TC) (WMD: 0.86; 95% CI: -0.42, 2.26), low-density lipoprotein cholesterols (LDL-C) (WMD: 0.49; 95% CI: -0.75, 2.74), apolipoprotein A (WMD: -3.15; 95% CI: -16.12, 9.81), and apolipoprotein B (WMD: -0.73; 95% CI: -9.87, 8.41) concentrations. However, CLA supplementation significantly increased the density lipoprotein cholesterol (HDL-C) (WMD: -0.40; 95% CI: -0.72, -0.07) concentrations. Conclusion CLA supplementation significantly improved HDL-C concentrations, however, increased concentrations of TG, TC, LDL-C, apolipoprotein A, and apolipoprotein B. Systematic review registration https://www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42022331100.
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Affiliation(s)
- Omid Asbaghi
- Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Damoon Ashtary-larky
- Nutrition and Metabolic Diseases Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Kaveh Naseri
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Saeede Saadati
- Department of Medicine, School of Clinical Sciences, Monash University, Melbourne, VIC, Australia
| | - Mohammad Zamani
- Department of Clinical Nutrition, School of Nutritional sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahnaz Rezaei Kelishadi
- Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Maryam Nadery
- Department of Dietetics and Nutrition, Robert Stempel College of Public Health & Social Work, Florida International University, Miami, FL, United States
| | - Saeid Doaei
- Reproductive Health Research Center, Department of Obstetrics and Gynecology, Al-Zahra Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
| | - Neda Haghighat
- Laparoscopy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Differential Inflammatory Responses in Cultured Endothelial Cells Exposed to Two Conjugated Linoleic Acids (CLAs) under a Pro-Inflammatory Condition. Int J Mol Sci 2022; 23:ijms23116101. [PMID: 35682781 PMCID: PMC9181016 DOI: 10.3390/ijms23116101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/21/2022] [Accepted: 05/26/2022] [Indexed: 12/04/2022] Open
Abstract
Conjugated linoleic acid (CLA) isomers have been shown to possess anti-atherosclerotic properties, which may be related to the downregulation of inflammatory pathways in different cell types, including endothelial cells (ECs). However, whether different CLA isomers have different actions is not entirely clear, with inconsistent reports to date. Furthermore, in cell culture studies, CLAs have often been used at fairly high concentrations. Whether lower concentrations of CLAs are able to affect EC responses is not clear. The aim of this study was to evaluate the effects of two CLAs (cis-9, trans-11 (CLA9,11) and trans-10, cis-12 (CLA10,12)) on the inflammatory responses of ECs. ECs (EA.hy926 cells) were cultured under standard conditions and exposed to CLAs (1 to 50 μM) for 48 h. Then, the cells were cultured for a further 6 or 24 h with tumour necrosis factor alpha (TNF-α, 1 ng/mL) as an inflammatory stimulant. ECs remained viable after treatments with 1 and 10 μM of each CLA, but not after treatment with 50 μM of CLA10,12. CLAs were incorporated into ECs in a concentration-dependent manner. CLA10,12 increased the levels of ICAM-1, IL-6, and RANTES in the culture medium, while CLA9,11 had null effects. Both CLAs (1 μM) decreased the appearance of NFκB1 mRNA, but only CLA9,11 maintained this downregulation at 10 μM. CLA10,12 had no effect on THP-1 cell adhesion to ECs while significantly decreasing the percentage of ECs expressing ICAM-1 and also levels of ICAM-1 expression per cell when used at 10 µM. Although CLA9,11 did not have any effect on ICAM-1 cell surface expression, it reduced THP-1 cell adhesion to the EA.hy926 cell monolayer at both concentrations. In summary, CLA10,12 showed some pro-inflammatory effects, while CLA9,11 exhibited null or anti-inflammatory effects. The results suggest that each CLA has different effects in ECs under a pro-inflammatory condition, highlighting the need to evaluate the effects of CLA isomers independently.
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Wiśniewski O, Rajczewski A, Szumigała A, Gibas-Dorna M. Diet-Induced Adipocyte Browning. POL J FOOD NUTR SCI 2021. [DOI: 10.31883/pjfns/143164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Pipoyan D, Stepanyan S, Stepanyan S, Beglaryan M, Costantini L, Molinari R, Merendino N. The Effect of Trans Fatty Acids on Human Health: Regulation and Consumption Patterns. Foods 2021; 10:2452. [PMID: 34681504 PMCID: PMC8535577 DOI: 10.3390/foods10102452] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 12/12/2022] Open
Abstract
Health effects of trans fatty acids (TFAs) on human organisms can vary according to their type, structure, composition, and origin. Even though the adverse health effects of industrial TFAs (iTFAs) have been widely discussed, the health effects of natural TFAs (nTFAs) are still questionable. Hence, it is important to review the literature and provide an overall picture on the health effects of different TFAs coming from industrial and ruminant sources, underlining those types that have adverse health effects as well as suggesting methods for reducing their harmful effects. Multiple databases (PubMed, Medline, Cochrane Library, etc.) were searched with the key words "trans fatty acid sources", "ruminant", "industrial", "conjugated trans linoleic acid", "human", "coronary heart disease", "cancer", etc. Reference lists of the studies were scanned discussing the health effects of iTFAs and nTFAs. The review of the literature showed that iTFAs are found to be more harmful than ruminant-produced nTFAs. Although several beneficial effects (such as reduced risk of diabetes) for nTFAs have been observed, they should be used with caution. Since during labeling it is usually not mentioned whether the TFAs contained in food are of industrial or natural origin, the general suggestion is to reduce their consumption.
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Affiliation(s)
- Davit Pipoyan
- Center for Ecological-Noosphere Studies of NAS RA, Abovyan 68, Yerevan 0025, Armenia; (D.P.); (S.S.); (S.S.); (M.B.)
| | - Stella Stepanyan
- Center for Ecological-Noosphere Studies of NAS RA, Abovyan 68, Yerevan 0025, Armenia; (D.P.); (S.S.); (S.S.); (M.B.)
| | - Seda Stepanyan
- Center for Ecological-Noosphere Studies of NAS RA, Abovyan 68, Yerevan 0025, Armenia; (D.P.); (S.S.); (S.S.); (M.B.)
| | - Meline Beglaryan
- Center for Ecological-Noosphere Studies of NAS RA, Abovyan 68, Yerevan 0025, Armenia; (D.P.); (S.S.); (S.S.); (M.B.)
| | - Lara Costantini
- Department of Ecological and Biological Sciences (DEB), Tuscia University, Largo dell’Università snc, 01100 Viterbo, Italy; (L.C.); (R.M.)
| | - Romina Molinari
- Department of Ecological and Biological Sciences (DEB), Tuscia University, Largo dell’Università snc, 01100 Viterbo, Italy; (L.C.); (R.M.)
| | - Nicolò Merendino
- Department of Ecological and Biological Sciences (DEB), Tuscia University, Largo dell’Università snc, 01100 Viterbo, Italy; (L.C.); (R.M.)
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10
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Bessell E, Maunder A, Lauche R, Adams J, Sainsbury A, Fuller NR. Efficacy of dietary supplements containing isolated organic compounds for weight loss: a systematic review and meta-analysis of randomised placebo-controlled trials. Int J Obes (Lond) 2021; 45:1631-1643. [PMID: 33976376 DOI: 10.1038/s41366-021-00839-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 04/07/2021] [Accepted: 04/26/2021] [Indexed: 02/04/2023]
Abstract
BACKGROUND/OBJECTIVES A systematic review with meta-analysis was conducted to synthesise evidence on the efficacy of dietary supplements containing isolated organic compounds for weight loss. SUBJECTS/METHODS Four electronic databases (Medline, Embase, Web of Science, Cinahl) were searched until December 2019. Sixty-seven randomised placebo-controlled trials of dietary supplements containing isolated organic compounds for weight loss were included. Meta-analyses were conducted for chitosan, glucomannan, conjugated linoleic acid and fructans, comparing mean weight difference post-intervention between participants receiving the dietary supplement or placebo. RESULTS Statistically significant weight differences compared to placebo were observed for chitosan (-1.84 kg; 95% confidence interval [CI] -2.79, -0.88; p < 0.01), glucomannan (-1.27 kg; 95%CI -2.45, -0.09; p = 0.04), and conjugated linoleic acid (-1.08 kg; 95%CI -1.61, -0.55; p < 0.01). None met our threshold for clinical significance (≥2.5 kg). There was no statistically significant effect on weight for fructans compared to placebo (p = 0.24). For dietary supplements with an inadequate number of trials for meta-analysis, a statistically and borderline clinically significant weight difference compared to placebo was found for modified cellulose, manno-oligosaccharides (in males), blood orange juice extract, and three multiple-ingredient dietary supplements. These were only reported in one trial of each. Thus, more evidence is needed before recommending them for weight loss. CONCLUSIONS While some dietary supplements containing isolated organic compounds warrant further investigation to determine efficacy and safety, there is currently insufficient evidence to recommend any of these dietary supplements for weight loss.
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Affiliation(s)
- Erica Bessell
- The University of Sydney, The Boden Collaboration for Obesity, Nutrition, Exercise & Eating Disorders, Charles Perkins Centre, Faculty of Medicine and Health, Sydney, NSW, Australia.
| | - Alison Maunder
- The University of Sydney, The Boden Collaboration for Obesity, Nutrition, Exercise & Eating Disorders, Charles Perkins Centre, Faculty of Medicine and Health, Sydney, NSW, Australia.,Western Sydney University, NICM Health Research Institute, Penrith, NSW, Australia
| | - Romy Lauche
- Southern Cross University, National Centre for Naturopathic Medicine, Lismore, NSW, Australia.,University of Technology Sydney, Australian Research Centre in Complementary and Integrative Medicine (ARCCIM), School of Public Health, Faculty of Health, Sydney, NSW, Australia
| | - Jon Adams
- University of Technology Sydney, Australian Research Centre in Complementary and Integrative Medicine (ARCCIM), School of Public Health, Faculty of Health, Sydney, NSW, Australia
| | - Amanda Sainsbury
- The University of Western Australia, School of Human Sciences, Faculty of Science, Perth, WA, Australia
| | - Nicholas R Fuller
- The University of Sydney, The Boden Collaboration for Obesity, Nutrition, Exercise & Eating Disorders, Charles Perkins Centre, Faculty of Medicine and Health, Sydney, NSW, Australia
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12
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Chang H, Gan W, Liao X, Wei J, Lu M, Chen H, Wang S, Ma Y, Wu Q, Yu Y, Liu X. Conjugated linoleic acid supplements preserve muscle in high-body-fat adults: A double-blind, randomized, placebo trial. Nutr Metab Cardiovasc Dis 2020; 30:1777-1784. [PMID: 32684362 DOI: 10.1016/j.numecd.2020.05.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND AIMS Conjugated linoleic acid (CLA) has been used to improve body composition in weight management. However, clinical trial results are inconsistent and limited among Asians. We aimed to investigate the effect of CLA on body composition of Chinese adults with elevated body fat percentage. METHODS AND RESULTS In this double-blind, randomized, placebo-controlled trial, 66 Chinese adults (aged 18-45 years old, 37.9% male) with elevated body fat percentage were provided with 3.2 g/day CLA (n = 33) or 3.2 g/day placebo (sunflower oil; n = 33) for 12 weeks. Both groups received lifestyle counseling, featured with low fat and low sugar diet, and moderate physical activity. Body composition was measured using dual-energy X-ray absorptiometry at the baseline and end of the trial. Sixty-four participants finished this study. Compared with the placebo group, the CLA group showed increased trunk muscle mass (MM) (0.6 ± 1.7 vs. -0.3 ± 1.2 kg, P = 0.019). Among those with an adherence score higher than 0.80 (n = 56, 87.5%), a greater increase in both total and trunk MM was observed in the CLA group (both P < 0.05). Moreover, the effect on MM appeared to be more evident in men, those with a body mass index <25 kg/m2, or those with higher self-rated physical activity. CONCLUSIONS In Chinese adults with elevated body fat percentage, 3.2 g/day CLA supplementation may be effective in preserving MM, especially in the trunk region. REGISTRATION This study was registered at ClinicalTrials.gov as NCT03915808 on April 9, 2019.
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Affiliation(s)
- Huan Chang
- Department of Nutrition and Food Safety, School of Public Health, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, 710061, Xi'an, Shaanxi, China
| | - Wei Gan
- Medical Research Council Population Health Research Unit at the University of Oxford, Oxford, OX3 7LF, UK; Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), Nuffield Department of Population Health, University of Oxford, Oxford, OX3 7LF, UK
| | - Xia Liao
- Department of Nutrition, The First Affiliated Hospital, Xi'an Jiaotong University Health Science Center, 277 West Yanta Road, 710061, Xi'an, Shaanxi, China
| | - Junxiang Wei
- Department of Epidemiology and Biostatistics, School of Public Health, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, 710061, Xi'an, Shaanxi, China
| | - Mengnan Lu
- Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, 710061, Xi'an, Shaanxi, China
| | - Huangtao Chen
- Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, 710061, Xi'an, Shaanxi, China
| | - Shenglong Wang
- Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, 710061, Xi'an, Shaanxi, China
| | - Yan Ma
- School of Sports and Health Sciences, Xi'an Physical Education University, 65 North Hanguang Road, 710068, Xi'an, Shaanxi, China
| | - Qian Wu
- Department of Epidemiology and Biostatistics, School of Public Health, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, 710061, Xi'an, Shaanxi, China
| | - Yan Yu
- Department of Nutrition and Food Safety, School of Public Health, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, 710061, Xi'an, Shaanxi, China.
| | - Xin Liu
- Department of Epidemiology and Biostatistics, School of Public Health, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, 710061, Xi'an, Shaanxi, China.
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Watanabe M, Risi R, Masi D, Caputi A, Balena A, Rossini G, Tuccinardi D, Mariani S, Basciani S, Manfrini S, Gnessi L, Lubrano C. Current Evidence to Propose Different Food Supplements for Weight Loss: A Comprehensive Review. Nutrients 2020; 12:E2873. [PMID: 32962190 PMCID: PMC7551574 DOI: 10.3390/nu12092873] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/14/2020] [Accepted: 09/18/2020] [Indexed: 02/06/2023] Open
Abstract
The use of food supplements for weight loss purposes has rapidly gained popularity as the prevalence of obesity increases. Navigating through the vast, often low quality, literature available is challenging, as is providing informed advice to those asking for it. Herein, we provide a comprehensive literature revision focusing on most currently marketed dietary supplements claimed to favor weight loss, classifying them by their purported mechanism of action. We conclude by proposing a combination of supplements most supported by current evidence, that leverages all mechanisms of action possibly leading to a synergistic effect and greater weight loss in the foreseen absence of adverse events. Further studies will be needed to confirm the weight loss and metabolic improvement that may be obtained through the use of the proposed combination.
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Affiliation(s)
- Mikiko Watanabe
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Renata Risi
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Davide Masi
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Alessandra Caputi
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Angela Balena
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Giovanni Rossini
- Department of Endocrinology and Diabetes, University Campus Bio-Medico of Rome, 00128 Rome, Italy; (G.R.); (D.T.); (S.M.)
| | - Dario Tuccinardi
- Department of Endocrinology and Diabetes, University Campus Bio-Medico of Rome, 00128 Rome, Italy; (G.R.); (D.T.); (S.M.)
| | - Stefania Mariani
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Sabrina Basciani
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Silvia Manfrini
- Department of Endocrinology and Diabetes, University Campus Bio-Medico of Rome, 00128 Rome, Italy; (G.R.); (D.T.); (S.M.)
| | - Lucio Gnessi
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
| | - Carla Lubrano
- Department of Experimental Medicine, Section of Medical Pathophysiology, Food Science and Endocrinology, Sapienza University of Rome, 00161 Rome, Italy; (M.W.); (D.M.); (A.C.); (A.B.); (S.M.); (S.B.); (L.G.); (C.L.)
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14
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Eighteen‑carbon trans fatty acids and inflammation in the context of atherosclerosis. Prog Lipid Res 2019; 76:101009. [PMID: 31669459 DOI: 10.1016/j.plipres.2019.101009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/17/2019] [Accepted: 09/19/2019] [Indexed: 12/12/2022]
Abstract
Endothelial dysfunction is a pro-inflammatory state characterized by chronic activation of the endothelium, which leads to atherosclerosis and cardiovascular disease (CVD). Intake of trans fatty acids (TFAs) is associated with an increased risk of CVD. This risk is usually associated with industrial TFAs (iTFAs) rather than ruminant TFAs (rTFAs); however it is not clear how specific TFA isomers differ in their biological activity and mechanisms of action with regard to inflammation. Here we review the literature on 18‑carbon TFAs, including the research associating their intake or levels with CVD and studies relating 18‑carbon TFA exposure to modulation of inflammatory processes. The evidence associating iTFAs with CVD risk factors is fairly consistent and studies in humans usually show a relation between iTFAs and higher levels of inflammatory markers. In contrast, studies in humans, animals and in vitro suggest that rTFAs have null or mildly beneficial effects in cardiovascular health, metabolic parameters and inflammatory markers, although the evidence is not always consistent. More studies are needed to better identify the beneficial and detrimental effects of the different TFAs, including those with 18 carbons.
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Wharton S, Bonder R, Jeffery A, Christensen RAG. The safety and effectiveness of commonly-marketed natural supplements for weight loss in populations with obesity: A critical review of the literature from 2006 to 2016. Crit Rev Food Sci Nutr 2019; 60:1614-1630. [PMID: 30896252 DOI: 10.1080/10408398.2019.1584873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Objective: To evaluate the evidence published from 2006 to 2016 on the effectiveness and safety of commonly used natural supplements for weight loss in individuals with obesity.Methods: Amazon and Google were searched for names of mono-agent natural supplements marketed for weight loss and a list of the 10 supplements was created. Google Scholar, Pubmed, Science Direct, and the Cochrane Library were searched for articles that met inclusion.Results: At least one article was published on the effectiveness or safety of bitter orange, capsinoid, carnitine, chromium picolinate, Coleus forskohlii, conjugated linoleic acid, glucomannan, green tea and psyllium for weight loss in populations with obesity from 2006 to 2016. There was insufficient evidence to suggest that the natural supplements examined contribute to significant weight loss, with the exception of perhaps glucomannan in the form of PGX. In general, the majority of side-effects reported were minor to moderate, and gastrointestinal-related. However, in some cases extreme side-effects such as liver and kidney failure were observed.Conclusion: Contrary to popular belief, results of this review suggest that the use of natural supplements for weight loss are unlikely to contribute to meaningful weight loss and in some cases may contribute to harm.
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Affiliation(s)
- Sean Wharton
- The Wharton Medical Clinic, Toronto, Ontario, Canada.,School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Revi Bonder
- School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Aaron Jeffery
- The Wharton Medical Clinic, Toronto, Ontario, Canada
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Conjugated Linoleic Acid Effects on Cancer, Obesity, and Atherosclerosis: A Review of Pre-Clinical and Human Trials with Current Perspectives. Nutrients 2019; 11:nu11020370. [PMID: 30754681 PMCID: PMC6413010 DOI: 10.3390/nu11020370] [Citation(s) in RCA: 158] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 02/03/2019] [Accepted: 02/08/2019] [Indexed: 02/07/2023] Open
Abstract
Obesity and its comorbidities, including type 2 diabetes and cardiovascular disease, are straining our healthcare system, necessitating the development of novel strategies for weight loss. Lifestyle modifications, such as exercise and caloric restriction, have proven effective against obesity in the short term, yet obesity persists because of the high predilection for weight regain. Therefore, alternative approaches to achieve long term sustainable weight loss are urgently needed. Conjugated linoleic acid (CLA), a fatty acid found naturally in ruminant animal food products, has been identified as a potential anti-obesogenic agent, with substantial efficacy in mice, and modest efficacy in obese human populations. Originally described as an anti-carcinogenic fatty acid, in addition to its anti-obesogenic effects, CLA has now been shown to possess anti-atherosclerotic properties. This review summarizes the pre-clinical and human studies conducted using CLA to date, which collectively suggest that CLA has efficacy against cancer, obesity, and atherosclerosis. In addition, the potential mechanisms for the many integrative physiological effects of CLA supplementation will be discussed in detail, including an introduction to the gut microbiota as a potential mediator of CLA effects on obesity and atherosclerosis.
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Namazi N, Irandoost P, Larijani B, Azadbakht L. The effects of supplementation with conjugated linoleic acid on anthropometric indices and body composition in overweight and obese subjects: A systematic review and meta-analysis. Crit Rev Food Sci Nutr 2019; 59:2720-2733. [PMID: 29672124 DOI: 10.1080/10408398.2018.1466107] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Clinical trials have indicated conflicting results on the effects of conjugated linoleic acid (CLA) on obesity. The present study aimed to systematically review controlled clinical trials examining the effects of CLA on anthropometric indices and body composition in overweight and obese subjects. Pubmed, Scopus, Web of science, and Cochrane databases were searched between 2000 and December 2017 with no language restriction. Placebo-controlled clinical trials that reported anthropometric indices and body composition in overweight and obese subjects were included. Random-effect model was used to pool the effect estimates. Of 4032 publications, 13 trials were included for the meta-analysis. Pooled effect sizes indicated that CLA significantly reduced body weight (WMD: -0.52 kg, 95% CI: -0.83, -0.21; I2: 48.0%, p = 0.01), BMI (WMD: -0.23 kg/m2, 95% CI: -0.39, - 0.06; I2: 64.7%, p = 0.0001), FM (WMD: -0.61 kg, 95% CI: -0.98, -0.24; I2: 53.8%, p = 0.01) and increased LBM (WMD: 0.19 kg, 95% CI: 0.04, 0.34; I2: 81.4%, p = 0.0001) compared to the placebo group. However, the effects of CLA on WC (WMD: 0.05 cm, 95% CI: -0.01, 0.1; I2: 0%, p = 0.93) was not significant. Additionally, its impact on body weight in subjects older than 44 year (WMD: -1.05 kg, 95% CI: -1.75, -0.35; I2: 57.0%, p = 0.01), with longer duration (more than 12 weeks) (WMD: -1.29 kg, 95% CI: -2.29, -0.29; I2: 70.3%, p = 0.003) and dosage more than 3.4 g/day (WMD: -0.77 kg, 95% CI: -1.28, -0.25; I2: 62.7%, p = 0.004) were greater than comparative groups. Supplementation with CLA can slightly reduce body weight and FM and increase LBM in overweight and obese subjects. However, its efficacy was not clinically considerable. Further studies with high methodological quality are needed to shed light on the effects of CLA on anthropometric indices in overweight and obese subjects.
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Affiliation(s)
- Nazli Namazi
- Obesity and Eating Habits Research Center, Endocrinology and Metabolism Molecular- Cellular Sciences Institute, Tehran University of Medical Sciences , Tehran , Iran
| | - Pardis Irandoost
- Department of Nutrition, School of Public Health, Iran University of Medical Sciences , Tehran , Iran
| | - Bagher Larijani
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences , Tehran , Iran
| | - Leila Azadbakht
- Diabetes Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences , Tehran , Iran.,Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences , Tehran , Iran.,Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences , Isfahan , Iran
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18
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Hegazy M, Elsayed NM, Ali HM, Hassan HG, Rashed L. Diabetes Mellitus, Nonalcoholic Fatty Liver Disease, and Conjugated Linoleic Acid (Omega 6): What Is the Link? J Diabetes Res 2019; 2019:5267025. [PMID: 31089474 PMCID: PMC6476070 DOI: 10.1155/2019/5267025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 03/05/2019] [Accepted: 03/18/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND AND OBJECTIVE Type 2 DM and obesity are the coming epidemics and their association with NAFLD is well established; essential fatty acids are vital for body health yet the body cannot make them; 2 essential fatty acids are especially important: linoleic (omega-6) and alpha-linoleic (omega-3) acids; they can be considered as "bioactive lipids" and serve as functional foods. METHODS 50 type 2 Egyptian diabetic patients controlled on oral hypoglycemic drugs together with 20 age- and sex-matched healthy participants were enrolled in the study; all were subjected to complete history taking, BMI, fasting plasma glucose, HOMA-IR, ALT, AST, GGT, urea and creatinine, total lipid profile, hepatitis markers including hepatitis B surface antigen and hepatitis C virus antibodies, conjugated linoleic fatty acid "CLA," and abdominal ultrasound for grading of NAFLD. RESULTS Our study in Egyptian diabetics with NAFLD revealed a low level of serum CLA compared to healthy control; such deficiency was more marked with advanced grades of NAFLD; lowest levels were observed in those with severe steatosis (NASH) with definite association between CLA and obesity. CONCLUSION Insulin resistance is the main link between NAFLD, diabetes, and obesity. Conjugated linoleic acid (CLA) has a role in fat deposition in the liver and in development and improvement of insulin resistance. Fatty food had a documented role in the pathogenesis of obesity and diabetes but it can also be the cure.
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Affiliation(s)
- Mona Hegazy
- Internal Medicine Department, Faculty of Medicine, Cairo University, Egypt
| | - Naglaa M. Elsayed
- Internal Medicine Department, Faculty of Medicine, Cairo University, Egypt
| | - Hala M. Ali
- Internal Medicine Department, Faculty of Medicine, Cairo University, Egypt
| | - Hanan G. Hassan
- Internal Medicine Department, Faculty of Medicine, Cairo University, Egypt
| | - Laila Rashed
- Biochemistry Department, Faculty of Medicine, Cairo University, Egypt
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Mazidi M, Karimi E, Rezaie P, Ferns GA. Effects of conjugated linoleic acid supplementation on serum C-reactive protein: A systematic review and meta-analysis of randomized controlled trials. Cardiovasc Ther 2018; 35. [PMID: 28556504 DOI: 10.1111/1755-5922.12275] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 05/06/2017] [Accepted: 05/22/2017] [Indexed: 02/06/2023] Open
Abstract
AIM To undertake a systematic review and meta-analysis of prospective studies to determine the effect of conjugated linoleic acids (CLAs) supplementation on serum C-reactive protein (CRP). METHOD PubMed-Medline, Web of Science, Cochrane Database, and Google Scholar databases were searched (up until May 2016) to identify prospective studies evaluating the impact of CLAs supplementation on serum CRP. Random-effects models meta-analysis was used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Heterogeneity was quantitatively assessed using the I2 index. Systematic review registration: CRD42016038945. RESULTS From a total of 85 entries identified via searches, 14 studies were included in the final selection. The meta-analysis indicated a significant increase in serum CRP concentrations following supplementation with CLAs (weighted mean difference [WMD] 0.63 mg/dL, 95% confidence interval [95% CI] 0.13-1.13, N=21 arms, heterogeneity P=.026; I2 =52.3%). These findings were robust in sensitivity analyses. Random-effects meta-regression revealed that changes in serum CRP levels were independent of the dosage of CLAs supplementation (slope: -0.02; 95% CI: -0.10, 0.12; P=.889) or duration of follow-up (slope: 0.271; 95% CI: -0.05, 0.59; P=.098). CONCLUSIONS This meta-analysis suggests that CLA supplementation is associated with an increase in plasma CRP concentrations and a reduction in serum adiponectin concentrations, which indicates that CLA supplements have a proinflammatory effect. Randomized control trials with larger sample size and a longer follow-up period may be required for future investigations to provide an unequivocal answer.
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Affiliation(s)
- Mohsen Mazidi
- Key State Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Institute of Genetics and Developmental Biology, International College, University of Chinese Academy of Science, Beijing, China
| | - Ehsan Karimi
- Biochemistry of Nutrition Research Center, School of Medicine, Mashhad University of Medical Science, Mashhad, Iran
| | - Peyman Rezaie
- Biochemistry of Nutrition Research Center, School of Medicine, Mashhad University of Medical Science, Mashhad, Iran
| | - Gordon A Ferns
- Division of Medical Education, Brighton and Sussex Medical School, Falmer, Brighton, UK
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20
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Chen PB, Yang JS, Park Y. Adaptations of Skeletal Muscle Mitochondria to Obesity, Exercise, and Polyunsaturated Fatty Acids. Lipids 2018; 53:271-278. [PMID: 29663395 DOI: 10.1002/lipd.12037] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 03/01/2018] [Accepted: 03/06/2018] [Indexed: 12/22/2022]
Abstract
Mitochondria intricately modulate their energy production through the control of mitochondrial adaptation (mitochondrial biogenesis, fusion, and/or fission) to meet energy demands. Nutrient overload may result in dysregulated mitochondrial biogenesis, morphology toward mitochondrial fragmentation, and oxidative stress in the skeletal muscle. In addition, physical activity and diet components influence mitochondrial function. Exercise may stimulate mitochondrial biogenesis and promote mitochondrial fusion/fission in the skeletal muscle. Moreover, some dietary fatty acids, such as n-3 polyunsaturated fatty acids and conjugated linoleic acid, have been identified to positively regulate mitochondrial adaptation in the skeletal muscle. This review discusses the association of mitochondrial impairments and obesity, and presents an overview of various mechanisms of which exercise training and mitochondrial nutrients promote mitochondrial function in the skeletal muscle.
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Affiliation(s)
- Phoebe B Chen
- Department of Food Science, University of Massachusetts, Amherst, 102 Holdsworth Way, Amherst, MA, 01003, USA
| | - Jason S Yang
- Department of Food Science, University of Massachusetts, Amherst, 102 Holdsworth Way, Amherst, MA, 01003, USA
| | - Yeonhwa Park
- Department of Food Science, University of Massachusetts, Amherst, 102 Holdsworth Way, Amherst, MA, 01003, USA
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21
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Haghighatdoost F, Nobakht M. Gh BF. Effect of conjugated linoleic acid on blood inflammatory markers: a systematic review and meta-analysis on randomized controlled trials. Eur J Clin Nutr 2017; 72:1071-1082. [DOI: 10.1038/s41430-017-0048-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/10/2017] [Accepted: 11/06/2017] [Indexed: 01/05/2023]
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Shen W, McIntosh MK. Nutrient Regulation: Conjugated Linoleic Acid's Inflammatory and Browning Properties in Adipose Tissue. Annu Rev Nutr 2017; 36:183-210. [PMID: 27431366 DOI: 10.1146/annurev-nutr-071715-050924] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Obesity is the most widespread nutritional disease in the United States. Developing effective and safe strategies to manage excess body weight is therefore of paramount importance. One potential strategy to reduce obesity is to consume conjugated linoleic acid (CLA) supplements containing isomers cis-9, trans-11 and trans-10, cis-12, or trans-10, cis-12 alone. Proposed antiobesity mechanisms of CLA include regulation of (a) adipogenesis, (b) lipid metabolism, (c) inflammation, (d) adipocyte apoptosis, (e) browning or beiging of adipose tissue, and (f) energy metabolism. However, causality of CLA-mediated responses to body fat loss, particularly the linkage between inflammation, thermogenesis, and energy metabolism, is unclear. This review examines whether CLA's antiobesity properties are due to inflammatory signaling and considers CLA's linkage with lipogenesis, lipolysis, thermogenesis, and browning of white and brown adipose tissue. We propose a series of questions and studies to interrogate the role of the sympathetic nervous system in mediating CLA's antiobesity properties.
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Affiliation(s)
- Wan Shen
- Department of Nutrition, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402; ,
| | - Michael K McIntosh
- Department of Nutrition, The University of North Carolina at Greensboro, Greensboro, North Carolina 27402; ,
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Enhancing the DHA content in milk from dairy cows by feeding ALL-G-RICH™. JOURNAL OF APPLIED ANIMAL NUTRITION 2017. [DOI: 10.1017/jan.2017.9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SummaryThe objective of this study was to evaluate the effect of the dietary inclusion of 6 g/kg dry matter intake of an unextracted Aurantiochytrium limacinum algae (AURA) in mid-lactation Italian Friesian cows under commercial conditions on milk yield, milk composition and docosahexaenoic acid (DHA) content. Cows were allocated to two groups (n = 18; 108.2 ± 66.1 and 104.4 ± 54.6 days in milk, control and treated groups, respectively). Feeding AURA for 84 d had no effect on dry matter intake, body condition score or weight gain, but did improve milk yield by 1.9 kg/cow/d (+5.4%; P < 0.1) over the course of the experiment. Milk fat concentration declined by 12% (P < 0.0001) without any significant change in 4% fat corrected milk, protein or lactose. Supplementing AURA for 12 weeks substantially altered the fatty acid profile of milk compared with milk from CON-fed cows such that the proportion of unsaturated fatty acids increased, omega-3 fatty acid content increased by 73.1% (P < 0.0001) and was accompanied by a favourable increase in the omega-3:6 fatty acid ratio by 75.0% (P < 0.0001). The AURA supplement, during day 7–84, increased the DHA concentration to 0.37 g /100 g milk total fatty acids (P < 0.0001) with a mean transfer efficiency of 18.1% from feed to milk. Together these results indicated that supplementing a dairy cow diet with DHA-rich microalgae is a feasible and efficient means for creating DHA-enriched milk for human consumption.
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Terasawa N, Okamoto K, Nakada K, Masuda K. Effect of Conjugated Linoleic Acid Intake on Endurance Exercise Performance and Anti-fatigue in Student Athletes. J Oleo Sci 2017. [PMID: 28626143 DOI: 10.5650/jos.ess17053] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Conjugated linoleic acids (CLA) intake has been reported to reduce body fat mass or increase lean body mass and to improve exercise outcome by modulating testosterone in humans. These reports have studied mostly overweight subjects; few were athletes. Therefore, in this study, the effect of CLA intake on endurance performance and anti-fatigue in student athletes was investigated. A double-blind, crossover study was conducted with 10 male student athletes. Each subject was administered with either CLA (net 0.9 g/day) or a placebo for 14 days. They were subjected to an exercise tolerance test (steady loading) using a cycle ergometer on days 0 and 14. Peak VO2 was determined for each subject using a graded loading test. The steady loading test was performed with a pedaling exercise load of 50% peak VO2 for 40 min and then with a load of 70% peak VO2 until exhaustion. Blood sampling and measurement of critical flicker frequency (CFF) were performed before and after exercise. The rate of perceived exertion (RPE) was measured serially during exercise. In the results, amount of body weight variation significantly increased and amount of body fat percentage variation tended to decrease by CLA intake, it might have an effect by increase in muscle mass. In addition, amount of exercise time variation significantly increased, amount of variation of CFF before and after exercise tended to increase, that of RPE during exercise tended to decrease, and that of creatine phosphokinase before and after exercise tended to decrease in the CLA group. These results suggested that CLA intake for 14 days might have an effect on endurance performance and anti-fatigue in student athletes.
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Affiliation(s)
| | - Ken Okamoto
- School of Regional Development Studies, College of Human and Social Sciences, Kanazawa University
| | - Kenta Nakada
- Division of Regional Development Studies, Graduate School of Human and Socio-Environmental Studies (Master's Level Section), Kanazawa University
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den Hartigh LJ, Wang S, Goodspeed L, Wietecha T, Houston B, Omer M, Ogimoto K, Subramanian S, Gowda GAN, O’Brien KD, Kaiyala KJ, Morton GJ, Chait A. Metabolically distinct weight loss by 10,12 CLA and caloric restriction highlight the importance of subcutaneous white adipose tissue for glucose homeostasis in mice. PLoS One 2017; 12:e0172912. [PMID: 28245284 PMCID: PMC5330530 DOI: 10.1371/journal.pone.0172912] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/10/2017] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Widely used as a weight loss supplement, trans-10,cis-12 conjugated linoleic acid (10,12 CLA) promotes fat loss in obese mice and humans, but has also been associated with insulin resistance. OBJECTIVE We therefore sought to directly compare weight loss by 10,12 CLA versus caloric restriction (CR, 15-25%), an acceptable healthy method of weight loss, to determine how 10,12 CLA-mediated weight loss fails to improve glucose metabolism. METHODS Obese mice with characteristics of human metabolic syndrome were either supplemented with 10,12 CLA or subjected to CR to promote weight loss. Metabolic endpoints such as energy expenditure, glucose and insulin tolerance testing, and trunk fat distribution were measured. RESULTS By design, 10,12 CLA and CR caused equivalent weight loss, with greater fat loss by 10,12 CLA accompanied by increased energy expenditure, reduced respiratory quotient, increased fat oxidation, accumulation of alternatively activated macrophages, and browning of subcutaneous white adipose tissue (WAT). Moreover, 10,12 CLA-supplemented mice better defended their body temperature against a cold challenge. However, 10,12 CLA concurrently induced the detrimental loss of subcutaneous WAT without reducing visceral WAT, promoted reduced plasma and WAT adipokine levels, worsened hepatic steatosis, and failed to improve glucose metabolism. Obese mice undergoing CR were protected from subcutaneous-specific fat loss, had improved hepatic steatosis, and subsequently showed the expected improvements in WAT adipokines, glucose metabolism and WAT inflammation. CONCLUSIONS These results suggest that 10,12 CLA mediates the preferential loss of subcutaneous fat that likely contributes to hepatic steatosis and maintained insulin resistance, despite significant weight loss and WAT browning in mice. Collectively, we have shown that weight loss due to 10,12 CLA supplementation or CR results in dramatically different metabolic phenotypes, with the latter promoting a healthier form of weight loss.
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Affiliation(s)
- Laura J. den Hartigh
- Department of Medicine, Metabolism, University of Washington, Seattle, Washington, United States of America
| | - Shari Wang
- Department of Medicine, Metabolism, University of Washington, Seattle, Washington, United States of America
| | - Leela Goodspeed
- Department of Medicine, Metabolism, University of Washington, Seattle, Washington, United States of America
| | - Tomasz Wietecha
- Department of Medicine, Cardiology, University of Washington, Seattle, Washington, United States of America
| | - Barbara Houston
- Department of Medicine, Metabolism, University of Washington, Seattle, Washington, United States of America
| | - Mohamed Omer
- Department of Medicine, Metabolism, University of Washington, Seattle, Washington, United States of America
| | - Kayoko Ogimoto
- Department of Medicine, Metabolism, University of Washington, Seattle, Washington, United States of America
| | - Savitha Subramanian
- Department of Medicine, Metabolism, University of Washington, Seattle, Washington, United States of America
| | - G. A. Nagana Gowda
- Northwest Metabolomics Research Center, Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, United States of America
| | - Kevin D. O’Brien
- Department of Medicine, Cardiology, University of Washington, Seattle, Washington, United States of America
| | - Karl J. Kaiyala
- Department of Oral Health Sciences, University of Washington, Seattle, Washington, United States of America
| | - Gregory J. Morton
- Department of Medicine, Metabolism, University of Washington, Seattle, Washington, United States of America
| | - Alan Chait
- Department of Medicine, Metabolism, University of Washington, Seattle, Washington, United States of America
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Dus-Zuchowska M, Madry E, Krzyzanowska P, Bogdanski P, Walkowiak J. Twelve-week-conjugated linoleic acid supplementation has no effects on the selected markers of atherosclerosis in obese and overweight women. Food Nutr Res 2016; 60:32776. [PMID: 27834186 PMCID: PMC5103664 DOI: 10.3402/fnr.v60.32776] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/23/2016] [Accepted: 09/23/2016] [Indexed: 11/29/2022] Open
Abstract
Background The antiatherogenic effect of conjugated linoleic acid (CLA) has been demonstrated in animal models. Although there are plenty of in vitro studies that suggest the profitable properties of CLA, the results in humans remain inconsistent. Objective In this study, we assessed the impact of CLA supplementation on the levels of atherosclerosis markers – high-sensitivity C-reactive protein (hs-CRP) and asymmetrical dimethylarginine (ADMA). Design Seventy-four adult female subjects with body mass index ≥25 kg/m2 were enrolled in the double-blind, placebo-controlled nutritional intervention. The study participants were randomly assigned to receive 3 g/day CLA or placebo (sunflower oil) for 12 weeks. In all subjects, we measured hs-CRP and ADMA concentrations by using enzyme-linked immunosorbent assay. Results No significant differences were found in hs-CRP and ADMA levels before and after nutritional intervention between both groups. The changes in hs-CRP and ADMA concentration values (Δhs-CRP; ΔADMA median [interquartile range]) did not differ between subjects from the placebo (−0.1 [−0.8 to 0.3]; −0.02 [−0.12 to 0.14]) and CLA (0.2 [−0.7 to 0.9]; 0.04 [−0.14 to 0.13]) groups. The incidence of reduction of hs-CRP or ADMA concentration was not different in subjects of the CLA group compared to those of the placebo group (41.9% vs. 50%, relative risk [RR]=0.8387, 95% confidence interval [CI]=0.4887–1.4493, p=0.5232 and 61.3% vs. 56.2%, RR=1.0896, 95% CI=0.7200–1.6589, p=0.6847, respectively). Conclusion Twelve weeks of CLA supplementation had no effect on selected markers of atherosclerosis in obese and overweight women.
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Affiliation(s)
- Monika Dus-Zuchowska
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, Poznan, Poland
| | - Edyta Madry
- Department of Physiology, Poznan University of Medical Sciences, Poznan, Poland
| | - Patrycja Krzyzanowska
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, Poznan, Poland
| | - Paweł Bogdanski
- Department of Education and Obesity Treatment and Metabolic Disorders, Poznan University of Medical Sciences, Poznan, Poland
| | - Jaroslaw Walkowiak
- Department of Pediatric Gastroenterology and Metabolic Diseases, Poznan University of Medical Sciences, Poznan, Poland;
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Mirzaii S, Mansourian M, Derakhshandeh-Rishehri SM, Kelishadi R, Heidari-Beni M. Association of conjugated linoleic acid consumption and liver enzymes in human studies: A systematic review and meta-analysis of randomized controlled clinical trials. Nutrition 2016; 32:166-73. [DOI: 10.1016/j.nut.2015.08.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 08/11/2015] [Accepted: 08/14/2015] [Indexed: 12/14/2022]
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Kim Y, Kim J, Whang KY, Park Y. Impact of Conjugated Linoleic Acid (CLA) on Skeletal Muscle Metabolism. Lipids 2016; 51:159-78. [PMID: 26729488 DOI: 10.1007/s11745-015-4115-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/16/2015] [Indexed: 12/17/2022]
Abstract
Conjugated linoleic acid (CLA) has garnered special attention as a food bioactive compound that prevents and attenuates obesity. Although most studies on the effects of CLA on obesity have focused on the reduction of body fat, a number of studies have demonstrated that CLA also increases lean body mass and enhances physical performances. It has been suggested that these effects may be due in part to physiological changes in the skeletal muscle, such as changes in the muscle fiber type transformation, alteration of the intracellular signaling pathways in muscle metabolism, or energy metabolism. However, the mode of action for CLA in muscle metabolism is not completely understood. The purpose of this review is to summarize the current knowledge of the effects of CLA on skeletal muscle metabolism. Given that CLA not only reduces body fat, but also improves lean mass, there is great potential for the use of CLA to improve muscle metabolism, which would have a significant health impact.
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Affiliation(s)
- Yoo Kim
- Department of Food Science, University of Massachusetts, 102 Holdsworth Way, Amherst, MA, 01003, USA
| | - Jonggun Kim
- Division of Biotechnology, Korea University, Seoul, 136-713, Republic of Korea
| | - Kwang-Youn Whang
- Division of Biotechnology, Korea University, Seoul, 136-713, Republic of Korea
| | - Yeonhwa Park
- Department of Food Science, University of Massachusetts, 102 Holdsworth Way, Amherst, MA, 01003, USA.
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Al-Khudairy L, Hartley L, Clar C, Flowers N, Hooper L, Rees K. Omega 6 fatty acids for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev 2015:CD011094. [PMID: 26571451 DOI: 10.1002/14651858.cd011094.pub2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Omega 6 plays a vital role in many physiological functions but there is controversy concerning its effect on cardiovascular disease (CVD) risk. There is conflicting evidence whether increasing or decreasing omega 6 intake results in beneficial effects. OBJECTIVES The two primary objectives of this Cochrane review were to determine the effectiveness of:1. Increasing omega 6 (Linoleic acid (LA), Gamma-linolenic acid (GLA), Dihomo-gamma-linolenic acid (DGLA), Arachidonic acid (AA), or any combination) intake in place of saturated or monounsaturated fats or carbohydrates for the primary prevention of CVD.2. Decreasing omega 6 (LA, GLA, DGLA, AA, or any combination) intake in place of carbohydrates or protein (or both) for the primary prevention of CVD. SEARCH METHODS We searched the following electronic databases up to 23 September 2014: the Cochrane Central Register of Controlled Trials (CENTRAL) on the Cochrane Library (Issue 8 of 12, 2014); MEDLINE (Ovid) (1946 to September week 2, 2014); EMBASE Classic and EMBASE (Ovid) (1947 to September 2014); Web of Science Core Collection (Thomson Reuters) (1990 to September 2014); Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment Database, and Health Economics Evaluations Database on the Cochrane Library (Issue 3 of 4, 2014). We searched trial registers and reference lists of reviews for further studies. We applied no language restrictions. SELECTION CRITERIA Randomised controlled trials (RCTs) of interventions stating an intention to increase or decrease omega 6 fatty acids, lasting at least six months, and including healthy adults or adults at high risk of CVD. The comparison group was given no advice, no supplementation, a placebo, a control diet, or continued with their usual diet. The outcomes of interest were CVD clinical events (all-cause mortality, cardiovascular mortality, non-fatal end points) and CVD risk factors (changes in blood pressure, changes in blood lipids, occurrence of type 2 diabetes). We excluded trials involving exercise or multifactorial interventions to avoid confounding. DATA COLLECTION AND ANALYSIS Two review authors independently selected trials for inclusion, extracted the data, and assessed the risk of bias in the included trials. MAIN RESULTS We included four RCTs (five papers) that randomised 660 participants. No ongoing trials were identified. All included trials had at least one domain with an unclear risk of bias. There were no RCTs of omega 6 intake reporting CVD clinical events. Three trials investigated the effect of increased omega 6 intake on lipid levels (total cholesterol, low density lipoprotein (LDL-cholesterol), and high density lipoprotein (HDL-cholesterol)), two trials reported triglycerides, and two trials reported blood pressure (diastolic and systolic blood pressure). Two trials, one with two relevant intervention arms, investigated the effect of decreased omega 6 intake on blood pressure parameters and lipid levels (total cholesterol, LDL-cholesterol, and HDL-cholesterol) and one trial reported triglycerides. Our analyses found no statistically significant effects of either increased or decreased omega 6 intake on CVD risk factors.Two studies were supported by funding from the UK Food Standards Agency and Medical Research Council. One study was supported by Lipid Nutrition, a commercial company in the Netherlands and the Dutch Ministry of Economic Affairs. The final study was supported by grants from the Finnish Food Research Foundation, Finnish Heart Research Foundation, Aarne and Aili Turnen Foundation, and the Research Council for Health, Academy of Finland. AUTHORS' CONCLUSIONS We found no studies examining the effects of either increased or decreased omega 6 on our primary outcome CVD clinical endpoints and insufficient evidence to show an effect of increased or decreased omega 6 intake on CVD risk factors such as blood lipids and blood pressure. Very few trials were identified with a relatively small number of participants randomised. There is a need for larger well conducted RCTs assessing cardiovascular events as well as cardiovascular risk factors.
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Affiliation(s)
- Lena Al-Khudairy
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK, CV4 7AL
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Benjamin S, Prakasan P, Sreedharan S, Wright ADG, Spener F. Pros and cons of CLA consumption: an insight from clinical evidences. Nutr Metab (Lond) 2015; 12:4. [PMID: 25972911 PMCID: PMC4429457 DOI: 10.1186/1743-7075-12-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 01/21/2015] [Indexed: 02/06/2023] Open
Abstract
This comprehensive review critically evaluates whether supposed health benefits propounded upon human consumption of conjugated linoleic acids (CLAs) are clinically proven or not. With a general introduction on the chemistry of CLA, major clinical evidences pertaining to intervention strategies, body composition, cardio-vascular health, immunity, asthma, cancer and diabetes are evaluated. Supposed adverse effects such as oxidative stress, insulin resistance, irritation of intestinal tract and milk fat depression are also examined. It seems that no consistent result was observed even in similar studies conducted at different laboratories, this may be due to variations in age, gender, racial and geographical disparities, coupled with type and dose of CLA supplemented. Thus, supposed promising results reported in mechanistic and pre-clinical studies cannot be extrapolated with humans, mainly due to the lack of inconsistency in analyses, prolonged intervention studies, follow-up studies and international co-ordination of concerted studies. Briefly, clinical evidences accumulated thus far show that CLA is not eliciting significantly promising and consistent health effects so as to uphold it as neither a functional nor a medical food.
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Affiliation(s)
- Sailas Benjamin
- Biotechnology Division, Department of Botany, Enzyme Technology Laboratory, University of Calicut, Kerala, 673 635 India
| | - Priji Prakasan
- Biotechnology Division, Department of Botany, Enzyme Technology Laboratory, University of Calicut, Kerala, 673 635 India
| | - Sajith Sreedharan
- Biotechnology Division, Department of Botany, Enzyme Technology Laboratory, University of Calicut, Kerala, 673 635 India
| | - Andre-Denis G Wright
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721 USA
| | - Friedrich Spener
- Department of Molecular Biosciences, University of Graz, Heinrichstrasse 31, 8010 Graz, Austria
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Niezgoda N, Gliszczyńska A, Gładkowski W, Kempińska K, Wietrzyk J, Wawrzeńczyk C. Phosphatidylcholine with cis-9,trans-11 and trans-10,cis-12 Conjugated Linoleic Acid Isomers: Synthesis and Cytotoxic Studies. Aust J Chem 2015. [DOI: 10.1071/ch14606] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Novel phosphatidylcholines and lysophosphatidylcholines with cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid (CLA) were synthesized in high yields (75–99 %). The in vitro cytotoxic activities of these compounds against three human cancer cell lines (HL-60, MCF-7, and HT-29) were evaluated. The results revealed that there are differences in the activity between phosphatidylcholine with cis-9,trans-11 and trans-10,cis-12 CLA acyl groups. 1,2-Di(9Z,11E)-octadecadienoyl-sn-glycero-3-phosphocholine was the most potent cytotoxic agent among all tested CLA derivatives and its IC50 (concentration of a compound that inhibits the proliferation of 50 % of the cancer cell population) was 29.4 µM against HL-60. Moreover, phosphatidylcholines with CLA acyls exhibited much lower cytotoxicity against non-cancer cells (Balb/3T3) than free CLA isomers.
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Association of foods enriched in conjugated linoleic acid (CLA) and CLA supplements with lipid profile in human studies: a systematic review and meta-analysis. Public Health Nutr 2014; 18:2041-54. [DOI: 10.1017/s1368980014002262] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AbstractObjectiveThe present study aimed to review the association of conjugated linoleic acid (CLA) consumption in two forms, foods enriched in CLA and CLA supplements, with serum lipid profile in human studies.DesignSystematic review and meta-analysis.SettingSearch process was conducted in PubMed, Cochrane Library, Google Scholar, Scopus and Science Direct. Clinical trials that investigated the association of CLA intakes either in the form of supplements or enriched foods with lipid profile in healthy adults were included. All outcomes were recorded as continuous variables, and the effect size was measured by analysis of the mean and standard deviation before and after the intervention for case and control groups.SubjectsHealthy adult population.ResultsCLA supplementation was associated with a significant decrease in LDL cholesterol (mean difference=−0·218; 95 % CI −0·358, −0·077;P=0·002), a non-significant decrease in HDL cholesterol (mean difference=−0·051; 95 % CI −0·188, 0·086;P=0·468), a non-significant increase in total cholesterol (mean difference=0·009; 95 % CI −0·128, 0·146;P=0·896) and a non-significant decrease in TAG (mean difference=−0·065; 95 % CI −0·20, 0·07;P=0·344). Foods enriched with CLA were associated with significantly decreased LDL cholesterol (mean difference=−0·231; 95 % CI −0·438, −0·024;P=0·028), non-significantly increased HDL-C (mean difference=0·075; 95 % CI −0·121, 0·270;P=0·455), non-significantly decreased total cholesterol (mean difference=−0·158; 95 % CI −0·349, 0·042;P=0·124) and non-significantly decreased TAG (mean difference=−0·078; 95 % CI −0·274, 0·117;P=0·433).ConclusionsAccording to our analysis, consumption of foods enriched with CLA or CLA supplements has favourable effects on LDL cholesterol levels.
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Penedo LA, Nunes JC, Gama MAS, Leite PEC, Quirico-Santos TF, Torres AG. Intake of butter naturally enriched with cis9,trans11 conjugated linoleic acid reduces systemic inflammatory mediators in healthy young adults. J Nutr Biochem 2014; 24:2144-51. [PMID: 24231103 DOI: 10.1016/j.jnutbio.2013.08.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 08/07/2013] [Accepted: 08/15/2013] [Indexed: 12/14/2022]
Abstract
A conjugated linoleic acid (CLA) depletion-repletion study was carried out to investigate the effects of dietary c9,t11 CLA on C-reactive protein, transcription factor NFκB, metalloproteinases 2 and 9, inflammatory mediators (adiponectin, TNFα, IL-2, IL-4, IL-8, IL-10), body composition, and erythrocyte membrane composition in healthy normal-weight human adults. CLA depletion was achieved through an 8-week period of restricted dairy fat intake (depletion phase; CLA intake was 5.2±5.8 mg/day), followed by an 8-week period in which individuals consumed 20 g/day of butter naturally enriched with c9,t11 CLA (repletion phase; CLA intake of 1020±167 mg/day). The participants were 29 healthy adult volunteers (19 women and 10 men, aged 22 to 36 years), with body mass index between 18.0 and 29.9 kg m(-2). Blood samples were collected at baseline and at the end of both depletion and repletion phases. The content of CLA in erythrocytes decreased during CLA-depletion and increased during CLA-repletion. Intake of CLA-enriched butter increased the serum levels of anti-inflammatory IL-10 but reduced transcription factor NFκB in blood and serum levels of TNFα, IL-2, IL-8 and inactive metalloproteinase-9. Moreover, reduced activity of metalloproteinases 2 and 9 in serum was observed during the CLA-repletion period. In contrast, intake of CLA-enriched butter had no effects on body composition (DXA analysis) as well as on serum levels of adiponectin, C-reactive protein, and IL-4. Taken together, our results indicate that the intake of a c9,t11 CLA-enriched butter by normal-weight subjects induces beneficial changes in immune modulators associated with sub-clinical inflammation in overweight individuals.
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Affiliation(s)
- Letícia A Penedo
- Laboratório de Bioquímica Nutricional e de Alimentos, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
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Rahman MM, Fernandes G, Williams P. Conjugated linoleic Acid prevents ovariectomy-induced bone loss in mice by modulating both osteoclastogenesis and osteoblastogenesis. Lipids 2013; 49:211-24. [PMID: 24338525 DOI: 10.1007/s11745-013-3872-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 11/27/2013] [Indexed: 11/29/2022]
Abstract
Postmenopausal osteoporosis due to estrogen deficiency is associated with severe morbidity and mortality. Beneficial effects of conjugated linoleic acid (CLA) on bone mineral density (BMD) have been reported in mice, rats and humans, but the effect of long term CLA supplementation against ovariectomy-induced bone loss in mice and the mechanisms underlying this effect have not been studied yet. Eight-week old ovariectomized (Ovx) and sham operated C57BL/6 mice were fed either a diet containing 0.5 % safflower oil (SFO) or 0.5 % CLA for 24 weeks to examine BMD, bone turn over markers and osteotropic factors. Bone marrow (BM) cells were cultured to determine the effect on inflammation, osteoclastogenesis, and osteoblastogenesis. SFO/Ovx mice had significantly lower femoral, tibial and lumbar BMD compared to SFO/Sham mice; whereas, no difference was found between CLA/Ovx and CLA/Sham mice. CLA inhibited bone resorption markers whereas enhanced bone formation markers in Ovx mice as compared to SFO-fed mice. Reverse transcriptase polymerase chain reaction and fluorescence activated cell sorting analyses of splenocytes revealed that CLA inhibited pro-osteoclastogenic receptor activator of NF-κB (RANKL) and stimulated decoy receptor of RANKL, osteoprotegerin expression. CLA also inhibited pro-inflammatory cytokine and enhanced anti-inflammatory cytokine production of lipopolysaccharide-stimulated splenocytes and BM cells. Furthermore, CLA inhibited osteoclast differentiation in BM and stimulated osteoblast differentiation in BM stromal cells as confirmed by tartrate resistant acid phosphatase and Alizarin Red staining, respectively. In conclusion, CLA may prevent postmenopausal bone loss not only by inhibiting excessive bone resorption due to estrogen deficiency but also by stimulating new bone formation. CLA might be a potential alternative therapy against osteoporotic bone loss.
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Affiliation(s)
- Md Mizanur Rahman
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229-3900, USA,
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Abstract
All fats, including saturated fatty acids, have important roles in the body. However, the most important fats are those that the body cannot make and thus must come from the food we eat. These essential fatty acids (EFAs) are based on linoleic acid (omega-6 group) and alpha-linolenic acid (omega-3 group). We need both groups of essential fatty acids to survive. For various reasons EFA deficiency is common in the general population, as is a disproportionate intake of omega-6 fatty acids over omega-3 fatty acids. As such, it is important to eat the right foods to make sure that you're taking in enough and the right kinds of the essential fatty acids. However, there is much more to the story. Studies have shown that increasing the intake of certain essential fatty acids, either alone or in combination with other fats and compounds, can increase health, help in treating certain diseases, and even improve body composition, mental and physical performance.
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Chinnadurai K, Kanwal HK, Tyagi AK, Stanton C, Ross P. High conjugated linoleic acid enriched ghee (clarified butter) increases the antioxidant and antiatherogenic potency in female Wistar rats. Lipids Health Dis 2013; 12:121. [PMID: 23923985 PMCID: PMC3766171 DOI: 10.1186/1476-511x-12-121] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 07/26/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Hypercholesterolemia and oxidative stress are the main stimulating factors responsible for coronary artery disease and progression of atherosclerosis. Dairy food products are rich in conjugated linoleic acid (CLA) which is considered as an important component due to its potential health benefits such as anticarcinogenic, antiatherogenic, antidiabetic and antiadipogenic properties. In the present study, the effect of CLA enriched ghee on the antioxidant enzyme system and antiatherogenic properties in Wistar rats has been studied. METHODS Female Wistar rats of 21 days were taken for the study and fed with soybean diet (Control diet), low CLA diet and high CLA ghee diet (treatments) for thirty five days for studying antioxidative enzymes and sixteen weeks in case of antiatherogenic studies. RESULTS Feeding of high CLA enhanced ghee during pubescent period in rats lead to an increase in catalase (CAT) and superoxide dismutase (SOD) enzyme activities in blood and increased CAT, SOD and glutathione transferase (GST) enzymes activities in liver by 27, 130 and 168 percent, respectively. Plasma nitrate concentration and Haemoglobin levels remained the same in all the treatments. Feeding of high CLA ghee resulted in lower (P < 0.01) plasma cholesterol & triglyceride level (52.17 and 30.27%), and higher high density lipoproteins (33.26%) than feeding of soybean oil (control group) and thus manifested in decreased (P < 0.05) atherogenic index (from 0.472 to 0.244). Lesser cholesterol and triglyceride levels were observed in the liver and aorta of high CLA fed rats than in those of the other groups. Histopathological studies of liver showed normal hepatic cords with portal triad in the high CLA ghee fed rats whereas fatty degeneration of hepatocytes containing fat vacuoles was observed in the liver of the other groups. CONCLUSION This paper is the first report of the antioxidant and antiatherogenic properties of the high CLA enriched ghee suggesting that high CLA ghee can be used as a potential food for decreasing the risk of cardiovascular diseases, particularly in India, where, ghee is widely used for culinary and medicinal purposes.
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Affiliation(s)
- Kathirvelan Chinnadurai
- Department of Animal Nutrition, Veterinary College and Research Institute, Namakkal, TamilNadu, 637 002, India
| | - Harpreet Kaur Kanwal
- Dairy Cattle Nutrition (DCN) Division, National Dairy Research Institute, Karnal, Haryana, 132001, India
| | - Amrish Kumar Tyagi
- Dairy Cattle Nutrition (DCN) Division, National Dairy Research Institute, Karnal, Haryana, 132001, India
| | - Catherine Stanton
- Teagasc, Moorepark Food Research Centre, Fermoy, County Cork, Ireland
| | - Paul Ross
- Teagasc, Moorepark Food Research Centre, Fermoy, County Cork, Ireland
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Shadman Z, Taleban FA, Saadat N, Hedayati M. Effect of conjugated linoleic acid and vitamin E on glycemic control, body composition, and inflammatory markers in overweight type2 diabetics. J Diabetes Metab Disord 2013; 12:42. [PMID: 23870044 PMCID: PMC7976596 DOI: 10.1186/2251-6581-12-42] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 07/05/2013] [Indexed: 01/12/2023]
Abstract
Background The healthy properties of conjugated linoleic acid (CLA) such as weight loss, reducing cardiovascular risk factors and inflammation have been reported. The trans-10, cis-12 CLA isomer is related to increasing insulin resistance, but the effects of cis-9, trans-11 isomer is not clear. The aim of this study was to investigate the effects of CLA with and without Vitamin E on body weight, body composition, glycemic index, inflammatory and coagulation factors, lipid profile, serum leptin and adiponectin, malondialdehyde (MDA), and blood pressure in type2 diabetes. Methods 56 patients with type2 diabetes were included in 8 week double-blind control trial that used metformin. They randomly divided into three groups: CLA + VitE, CLA + VitE placebo, CLA placebo + VitE placebo. All variables, anthropometric measurements, and body composition were evaluated at the beginning and the end of study. Statistical analysis and analysis of dietary data were performed using SPSS and nutritionist IV software, respectively. Results There were not any significant differences in variable changes among three groups. However, there was a trend to increase in MDA and decrease in apoB100 among CLA consumers. Conclusion The results of this study showed that administration of CLA supplementation for 8 weeks does not affect any indicators of metabolic control in overweight type2 diabetic patients.
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Affiliation(s)
- Zhaleh Shadman
- Cellular and Molecular Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Mohammadzadeh M, Faramarzi E, Mahdavi R, Nasirimotlagh B, Asghari Jafarabadi M. Effect of conjugated linoleic acid supplementation on inflammatory factors and matrix metalloproteinase enzymes in rectal cancer patients undergoing chemoradiotherapy. Integr Cancer Ther 2013; 12:496-502. [PMID: 23632235 DOI: 10.1177/1534735413485417] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES The aims of this study were to determine the effect of conjugated linoleic acid (CLA) supplementation on inflammatory factors and matrix metalloproteinase (MMP) enzymes in rectal cancer patients undergoing chemoradiothetrapy. METHOD AND MATERIAL In this randomized, double-blind, placebo-controlled pilot study, 34 volunteer patients with rectal cancer undergoing chemoradiotherapy assigned into the CLA group (n = 16), receiving 3 g CLA/d, and placebo group (n = 18) receiving placebo capsules (sunflower oil) for 6 weeks. The supplementation began 1 week before starting RT (loading period) and continued every day during treatment. Before and after intervention, serum tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), IL-6, MMP-2, MMP-9, and high-sensitivity C-reactive protein (hsCRP) were measured by enzyme-linked immunosorbent assay (ELISA) kits and immunoturbidimetric method, respectively. Independent t tests and paired t tests were used to compare parameters between and within groups, respectively. RESULTS In the CLA group, the mean serum TNF-α, IL-1β, hsCRP, MMP-9, and MMP-2 levels reduced insignificantly. However, significant changes in TNF-α (P = 0.04), hsCRP (P = 0.03), and MMP-9 (P = 0.04) concentrations were observed in the CLA group when compared with the placebo group. The mean serum IL-6 level remained unchanged in the CLA group but increased remarkably in the placebo group. CONCLUSION According to our results, CLA supplementation improved inflammatory factors, MMP-2, and MMP-9 as biomarkers of angiogenesis and tumor invasion. It seems that CLA may provide new complementary treatment by reducing tumor invasion and resistance to cancer treatment in patients with rectal cancer.
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Brouwer IA, Wanders AJ, Katan MB. Trans fatty acids and cardiovascular health: research completed? Eur J Clin Nutr 2013; 67:541-7. [DOI: 10.1038/ejcn.2013.43] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Deguire JR, Makarem N, Vanstone CA, Morin S, Duque G, Weiler HA. Conjugated linoleic acid is related to bone mineral density but does not affect parathyroid hormone in men. Nutr Res 2012; 32:911-20. [PMID: 23244536 DOI: 10.1016/j.nutres.2012.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 08/09/2012] [Accepted: 08/13/2012] [Indexed: 11/15/2022]
Abstract
The relationships between conjugated linoleic acid (CLA) status, bone, body composition, and the effect of CLA on calciotropic hormones are unclear. A cross-sectional study was designed to examine the association between c9, t11 CLA status in erythrocyte membranes (RBC) and body composition. This preceded a dose-response trial investigating if c9, t11 CLA affected parathyroid hormone (PTH). It was hypothesized that (1) higher c9, t11 CLA status in RBC will be associated with a lower fat and higher bone mass and that (2) PTH will be reduced by 30% after supplementation of c9, t11 CLA. Fifty-four men (age, 19-53 years) were included in the cross-sectional analysis, of which 31 were studied in the dose-response trial and randomized to 1 of 3 groups: placebo (n = 10), 1.5 g/d (n = 11), or 3.0 g/d (n = 10) of c9, t11 CLA for 16 weeks. Men with RBC c9, t11 CLA status above the median had higher whole body bone mineral density (BMD) (1.359 ± 0.024 vs 1.287 ± 0.023 g/cm(2); P = .04) and whole body lean mass (WBL) percentage (78.8% ± 0.9% vs 75.3% ± 1.0%; P = .01), whereas body mass index (24.8 ± 0.5 kg/m(2) vs 27.3 ± 0.9 kg/m(2); P = .01) and whole body fat mass percentage (17.3% ± 0.9% vs 21.3% ± 1.1%; P = .007) were lower. In regression analysis, RBC c9, t11 CLA status accounted for a significant proportion (r(2) = 0.10) of the variation in whole body BMD (P = .03). There were no time or treatment differences among any bone or biomarkers of bone metabolism including PTH. These findings indicate that RBC c9, t11 CLA status, a reflection of long-term (~4 months) dietary CLA intake, positively relates to BMD. However, c9, t11 CLA supplementation does not appear to affect PTH in healthy men.
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Affiliation(s)
- Jason R Deguire
- School of Dietetics and Human Nutrition, McGill University, Montreal, Quebec, Canada
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Abstract
Conjugated linoleic acid (CLA) has drawn significant attention in the last two decades for its variety of biologically beneficial effects. CLA reduces body fat, cardiovascular diseases and cancer, and modulates immune and inflammatory responses as well as improves bone mass. It has been suggested that the overall effects of CLA are the results of interactions between two major isomers, cis-9,trans-11 and trans-10,cis-12. This review will primarily focus on current CLA publications involving humans, which are also summarized in the tables. Along with a number of beneficial effects of CLA, there are safety considerations for CLA supplementation in humans, which include effects on liver functions, milk fat depression, glucose metabolism, and oxidative stresses.
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Affiliation(s)
- Allison Dilzer
- Department of Food Science, University of Massachusetts, Amherst, Amherst , MA 01003, USA
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Abstract
The primary purpose of the present review was to determine if the scientific evidence available for potential human health benefits of conjugated linoleic acid (CLA) is sufficient to support health claims on foods based on milk naturally enriched with cis-9, trans-11-CLA (c9, t11-CLA). A search of the scientific literature was conducted and showed that almost all the promising research results that have emerged in relation to cancer, heart health, obesity, diabetes and bone health have been in animal models or in vitro. Most human intervention studies have utilised synthetic CLA supplements, usually a 50:50 blend of c9, t11-CLA and trans-10, cis-12-CLA (t10, c12-CLA). Of these studies, the only evidence that is broadly consistent is an effect on body fat and weight reduction. A previous review of the relevant studies found that 3.2 g CLA/d resulted in a modest body fat loss in human subjects of about 0.09 kg/week, but this effect was attributed to the t10, c12-CLA isomer. There is no evidence of a consistent benefit of c9, t11-CLA on any health conditions; and in fact both synthetic isomers, particularly t10, c12-CLA, have been suspected of having pro-diabetic effects in individuals who are already at risk of developing diabetes. Four published intervention studies using naturally enriched CLA products were identified; however, the results were inconclusive. This may be partly due to the differences in the concentration of CLA administered in animal and human studies. In conclusion, further substantiation of the scientific evidence relating to CLA and human health benefits are required before health claims can be confirmed.
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Chen SC, Lin YH, Huang HP, Hsu WL, Houng JY, Huang CK. Effect of conjugated linoleic acid supplementation on weight loss and body fat composition in a Chinese population. Nutrition 2012; 28:559-65. [PMID: 22261578 DOI: 10.1016/j.nut.2011.09.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 07/09/2011] [Accepted: 09/10/2011] [Indexed: 10/14/2022]
Abstract
OBJECTIVE Conjugated linoleic acid (CLA) has several benefits, including body fat reduction, as proved in animals. However, the results of CLA-induced body composition alterations in humans are inconsistent, and no related data are available for Chinese populations. This study aimed to determine whether CLA affects body weight (BW) loss and body composition of overweight and obese Chinese subjects. METHODS In this randomized, double-blind, placebo-controlled trial, subjects with a body mass index (BMI) of 24 to 35 kg/m(2) randomly received 1.7 g of cis-9,trans-11 and trans-10,cis-12 CLA (n = 30) or placebo (salad oil; n = 33) in 200 mL of sterilized milk twice daily for 12 wk. Changes in body composition were determined by bioimpedance measurements. RESULTS Sixty-three subjects completed the study (CLA, n = 30). After 12 wk, compared with the baseline, the BW, BMI, total fat mass, fat percentage, subcutaneous fat mass, and waist-to-hip ratio decreased in the CLA group (P < 0.05). The CLA group was stratified by BMI and gender. The BW, BMI, subcutaneous fat mass, and waist-to-hip ratio decreased in 27 subjects with a BMI ≥ 27, and these indices, except subcutaneous fat mass, were lower in female subjects. The levels of total cholesterol, triacylglycerol, low-density lipoprotein, and plasma fasting glucose increased, whereas those of high-density lipoprotein decreased after 3 mo of CLA treatment. The changes were not significantly different from the baseline values. CONCLUSION The supplementation of CLA for 12 wk in overweight and grade I obese Chinese subjects yielded lower obesity indices, with no obvious adverse effects.
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Affiliation(s)
- Shu-Chiun Chen
- Department of Surgery, Kaohsiung Veterans General Hospital Pingtung Branch, Pingtung, Taiwan
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Fernandes SAT, Natali AJ, Laterza MC, Teodoro BG, Franco FSC, Peluzio MDCG. Ácido linoléico conjugado: efeitos no perfil lipídico e na composição corporal de camundongos exercitados. MOTRIZ: REVISTA DE EDUCACAO FISICA 2011. [DOI: 10.1590/s1980-65742011000400013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Objetivo: Avaliar os efeitos do CLA associado à dieta hiperlipídica sobre o perfil lipídico e composição corporal de camundongos knockout para o gene da ApoE exercitados. Métodos: 32 camundongos foram divididos e submetidos à dieta normo e hiperlipídica suplementadas ou não com 1% de CLA. Todos realizaram exercício físico em esteira, durante 12 semanas. Utilizou-se o teste de Kruskal-Wallis ao nível de significância de 5%. Resultados: Os animais que ingeriram dieta hiperlipídica com CLA aumentaram o colesterol total e o LDL, comparado com os alimentados com dieta normolipídica associada ou não ao CLA. Observou-se aumento no ganho de peso dos camundongos que ingeriram dieta hiperlipídica com CLA, comparado com os normolipídicos suplementados com CLA. Conclusões: O CLA na concentração de 1% não alterou nenhum dos parâmetros analisados, independente da dieta, e não foi protetor contra os efeitos da dieta hiperlipídica.
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Martinez K, Kennedy A, McIntosh M. JNK inhibition by SP600125 attenuates trans-10, cis-12 conjugated linoleic acid-mediated regulation of inflammatory and lipogenic gene expression. Lipids 2011; 46:885-92. [PMID: 21744278 PMCID: PMC3167035 DOI: 10.1007/s11745-011-3587-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 06/20/2011] [Indexed: 10/18/2022]
Abstract
Supplementation with a mixture of trans-10, cis-12 (t10,c12) and cis-9, trans-11 (c9,t11) isomers of conjugated linoleic acid (CLA), or t10,c12 CLA alone, reduces body weight and fat deposition in animals and some humans. However, these anti-obesity actions of t10,c12 CLA are routinely accompanied by increased markers of inflammation and insulin resistance. Thus, we examined the extent to which blocking c-Jun NH2-terminal kinase (JNK) signaling using the JNK inhibitor SP600125 attenuated markers of inflammation and insulin resistance in primary human adipocytes treated with t10,c12 CLA. SP600125 attenuated t10,c12 CLA-mediated phosphorylation of cJun and increased protein levels of activating transcription factor (ATF) 3, two downstream targets of JNK. SP600125 attenuated t10,c12 CLA-mediated induction of inflammatory genes, including interleukin (IL)-6, IL-8, IL-1β, ATF3, monocyte chemoattractant protein (MCP)-1, and cyclooxygenase-2. Consistent with these data, SP600125 prevented t10,c12 CLA-mediated secretion of IL-8, IL-6, and MCP-1. SP600125 prevented t10,c12 CLA suppression of lipogenic genes including peroxisome proliferator activated receptor gamma, liver X receptor, sterol regulatory element binding protein, acetyl-CoA carboxylase, and stearoyl-CoA desaturase. Additionally, SP600125 blocked t10,c12 CLA-mediated induction of suppressor of cytokine synthesis-3 and suppression of adiponectin and insulin-dependent glucose transporter 4 mRNA levels. Collectively, these data suggest that JNK signaling plays an important role in t10,c12 CLA-mediated regulation of inflammatory and lipogenic gene expression in primary cultures of human adipocytes.
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Affiliation(s)
- Kristina Martinez
- Department of Nutrition, University of North Carolina at Greensboro, Greensboro, NC 27402, USA, ,
| | - Arion Kennedy
- Department of Molecular Physiology, Vanderbilt U. Medical Ctr, Nashville, TN 37232, USA, (Version 6-20-11)
| | - Michael McIntosh
- Department of Nutrition, University of North Carolina at Greensboro, Greensboro, NC 27402, USA, ,
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Jutzeler van Wijlen RP. Long-term conjugated linoleic acid supplementation in humans - effects on body composition and safety. EUR J LIPID SCI TECH 2011. [DOI: 10.1002/ejlt.201100130] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Smit LA, Katan MB, Wanders AJ, Basu S, Brouwer IA. A high intake of trans fatty acids has little effect on markers of inflammation and oxidative stress in humans. J Nutr 2011; 141:1673-8. [PMID: 21753062 DOI: 10.3945/jn.110.134668] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Consumption of industrial trans fatty acids (iTFA) increases LDL cholesterol, decreases HDL cholesterol, and is strongly associated with a higher risk of cardiovascular disease (CVD). However, changes in circulating cholesterol cannot explain the entire effect. Therefore, we studied whether iTFA and conjugated linoleic acid (CLA) affect markers of inflammation and oxidative stress. Sixty-one healthy adults consumed each of 3 diets for 3 wk, in random order. Diets were identical except for 7% of energy provided by oleic acid (control diet), iTFA, or CLA. At the end of the 3 wk, we measured plasma inflammatory markers IL-6, C-reactive protein, tumor necrosis factor receptors I and II (TNF-RI and -RII), monocyte chemotactic protein-1 and E-selectin, and urinary 8-iso-PGF(2α), a marker of lipid peroxidation. Consumption of iTFA caused 4% lower TNF-RI concentrations and 6% higher E-selectin concentrations compared with oleic acid (control) and had no significant effect on other inflammatory markers. CLA did not significantly affect inflammatory markers. The urine concentration of 8-iso-PGF(2α) [geometric mean (95% CI)] was greater after the iTFA [0.54 (0.48, 0.60) nmol/mmol creatinine] and the CLA [1.2 (1.1, 1.3) nmol/mmol creatinine] diet periods than after the control period [0.45 (0.41, 0.50) nmol/mmol creatinine; P < 0.05]. In conclusion, high intakes of iTFA and CLA did not substantially affect plasma concentrations of inflammatory markers, but they increased the urine 8-iso-PGF(2α) concentration. However, it is unlikely this plays a major role in the mechanism by which iTFA increase the risk of CVD. However, more research is needed to fully understand the implications of these findings.
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Affiliation(s)
- Liesbeth A Smit
- Department of Health Sciences and the EMGO Institute for Health and Care Research, Faculty of Earth and Life Sciences, VU University, Amsterdam, The Netherlands
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Joseph SV, Jacques H, Plourde M, Mitchell PL, McLeod RS, Jones PJH. Conjugated linoleic acid supplementation for 8 weeks does not affect body composition, lipid profile, or safety biomarkers in overweight, hyperlipidemic men. J Nutr 2011; 141:1286-91. [PMID: 21593349 DOI: 10.3945/jn.110.135087] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The usefulness of conjugated linoleic acid (CLA) as a nutraceutical remains ambiguous. Our objective was, therefore, to investigate the effect of CLA on body composition, blood lipids, and safety biomarkers in overweight, hyperlipidemic men. A double-blinded, 3-phase crossover trial was conducted in overweight (BMI ≥ 25 kg/m(2)), borderline hypercholesterolemic [LDL-cholesterol (C) ≥ 2.5 mmol/L] men aged 18-60 y. During three 8-wk phases, each separated by a 4-wk washout period, 27 participants consumed under supervision in random order 3.5 g/d of safflower oil (control), a 50:50 mixture of trans 10, cis 12 and cis 9, trans 11 (c9, t11) CLA:Clarinol G-80, and c9, t11 isomer:c9, t11 CLA. At baseline and endpoint of each phase, body weight, body fat mass, and lean body mass were measured by DXA. Blood lipid profiles and safety biomarkers, including insulin sensitivity, blood concentrations of adiponectin, and inflammatory (high sensitive-C-reactive protein, TNFα, and IL-6) and oxidative (oxidized-LDL) molecules, were measured. The effect of CLA consumption on fatty acid oxidation was also assessed. Compared with the control treatment, the CLA treatments did not affect changes in body weight, body composition, or blood lipids. In addition, CLA did not affect the β-oxidation rate of fatty acids or induce significant alterations in the safety markers tested. In conclusion, although no detrimental effects were caused by supplementation, these results do not confirm a role for CLA in either body weight or blood lipid regulation in humans.
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Affiliation(s)
- Shama V Joseph
- Department of Food Science and Nutrition, and Institute of Nutraceuticals and Functional Foods, Laval University, Quebec, QC G1V 0A6, Canada
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Dietary modulation of body composition and insulin sensitivity during catch-up growth in rats: effects of oils rich in n-6 or n-3 PUFA. Br J Nutr 2011; 105:1750-63. [PMID: 21281526 DOI: 10.1017/s0007114510005659] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The present study investigates whether excessive fat accumulation and hyperinsulinaemia during catch-up growth on high-fat diets are altered by n-6 and n-3 PUFA derived from oils rich in either linoleic acid (LA), α-linolenic acid (ALA), arachidonic acid (AA) or DHA. It has been shown that, compared with food-restricted rats refed a high-fat (lard) diet low in PUFA, those refed isoenergetically on diets enriched in LA or ALA, independently of the n-6:n-3 ratio, show improved insulin sensitivity, lower fat mass and higher lean mass, the magnitude of which is related to the proportion of total PUFA precursors (LA+ALA) consumed. These relationships are best fitted by quadratic regression models (r2>0·8, P < 0·001), with threshold values for an impact on body composition corresponding to PUFA precursors contributing 25-30 % of energy intake. Isoenergetic refeeding on high-fat diets enriched in AA or DHA also led to improved body composition, with increases in lean mass as predicted by the quadratic model for PUFA precursors, but decreases in fat mass, which are disproportionately greater than predicted values; insulin sensitivity, however, was not improved. These findings pertaining to the impact of dietary intake of PUFA precursors (LA and ALA) and their elongated-desaturated products (AA and DHA), on body composition and insulin sensitivity, provide important insights into the search for diets aimed at counteracting the pathophysiological consequences of catch-up growth. In particular, diets enriched in essential fatty acids (LA and/or ALA) markedly improve insulin sensitivity and composition of weight regained, independently of the n-6:n-3 fatty acid ratio.
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Venkatramanan S, Joseph SV, Chouinard PY, Jacques H, Farnworth ER, Jones PJH. Milk enriched with conjugated linoleic acid fails to alter blood lipids or body composition in moderately overweight, borderline hyperlipidemic individuals. J Am Coll Nutr 2010; 29:152-9. [PMID: 20679151 DOI: 10.1080/07315724.2010.10719829] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Dietary conjugated linoleic acid (CLA) represents a group of positional and geometric isomers of conjugated dienoic derivatives of linoleic acid. The effects of dietary CLA on blood lipids and body composition in humans remain controversial. OBJECTIVE To examine whether consumption of milk enriched naturally or synthetically with cis 9, trans 11 (c-9, t-11) and trans 10, cis 12 (t-10, c-12) CLA isomers alters blood lipid indices, including concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triacyglycerol; indices of liver function including plasma alanine transaminase and total bilirubin; C-reactive protein; tumor necrosis factor-alpha; and body weight and composition in moderately overweight, borderline hyperlipidemic humans. DESIGN A randomized, 3-phase, crossover, single-blind clinical trial was carried out in moderately overweight, borderline hyperlipidemic individuals who consumed (1) milk naturally enriched in CLA (4.2%) containing c-9, t-11 only providing 1.3 g/d of CLA; (2) milk enriched with a 4.2% synthetic mixture of t-10, c-12 and c-9, t-11 CLA isomers providing 1.3 g/d of CLA; or (3) untreated milk as a control providing 0.2 g/d CLA. Dietary phases were each 8 weeks in duration and were separated by 4-week washout periods. Plasma lipid levels were measured in blood samples collected at the beginning and end of each dietary phase. Magnetic resonance imaging was carried out at the beginning and end of each dietary phase to assess any changes in regional body fat composition. RESULTS Compared with the control intervention, consumption of the two CLA-enriched milks failed to alter plasma total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or triacyglycerol concentrations; body weight; or fat composition. CLA consumption did not significantly affect plasma alanine transaminase, total bilirubin, C-reactive protein, or tumor necrosis factor-alpha concentrations. CONCLUSION Results from this study fail to support the role of milk enriched naturally with CLA containing c-9, t-11 or synthetically with c-9, t-11 and t-10, c-12 CLA isomers in modulation of lipid profiles or body composition in moderately overweight, borderline hyperlipidemic individuals.
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Affiliation(s)
- Sudha Venkatramanan
- Richardson Centre for Functional Foods and Nutraceuticals, 196 Innovation Drive, Smartpark, University of Manitoba, Winnipeg, Manitoba R3T 6C5, Canada
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