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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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Liang CW, Cheng HY, Lee YH, Liou TH, Liao CD, Huang SW. Effects of conjugated linoleic acid and exercise on body composition and obesity: a systematic review and meta-analysis. Nutr Rev 2023; 81:397-415. [PMID: 36048508 DOI: 10.1093/nutrit/nuac060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
CONTEXT Conjugated linoleic acid (CLA) has been reported to have anti-obesity and antidiabetic effects. However, the benefits of CLA combined with exercise remain unclear, and studies report conflicting results. OBJECTIVE A systematic review and meta-analysis were performed to investigate the synergistic effect of CLA and exercise on body composition, exercise-related indices, insulin resistance, and lipid profiles; and of the safety of CLA supplements. DATA SOURCES In October 2021, the PubMed, Embase, and Cochrane Library databases were searched for reports on clinical trials of the combined intervention of CLA and exercise. DATA EXTRACTION A total of 18 randomized controlled trials and 2 crossover trials were included. The methodological quality assessment was performed using the revised Cochrane risk-of-bias tool. Pooled effect sizes were reported as standardized mean difference (SMD) for continuous data and risk ratio for dichotomous data with their corresponding 95% confidence intervals (CIs). Heterogeneity was tested using the I2 statistic. DATA ANALYSIS The combination of CLA and exercise resulted in significantly decreased body fat (SMD, -0.42 [95%CI, -0.70, -0.14]; P = 0.003; I2 = 65) and insulin resistance (SMD, -0.25 [95%CI, -0.44, -0.06]; P = 0.01; I2 = 0) than did exercise alone. In subgroup analysis, the following factors were associated with significant outcomes: (1) body mass index ≥25 kg/m2; (2) female sex; (3) follow-up time >4 weeks; and (4) intervention duration >4 weeks. Nevertheless, supplementation with CLA during exercise programs was not effective for body-weight control, exercise performance enhancement, or lipid-profile improvement. CLA in combination with exercise did not result in a higher risk of adverse events (risk ratio, 1.32 [95%CI, 0.94-1.84]; P > 0.05; I2 = 0). CONCLUSION CLA combined with exercise is generally safe and can lower body fat and insulin resistance but does not reduce body weight, enhance exercise performance, or improve lipid profiles.
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Affiliation(s)
- Chun-Wei Liang
- are with the School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Hsiao-Yi Cheng
- are with the School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yu-Hao Lee
- are with the Department of Physical Medicine and Rehabilitation, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.,are with the Department of Physical Medicine and Rehabilitation, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tsan-Hon Liou
- are with the Department of Physical Medicine and Rehabilitation, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.,are with the Department of Physical Medicine and Rehabilitation, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chun-De Liao
- are with the Department of Physical Medicine and Rehabilitation, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.,is with the Master Program in Long-Term Care, College of Nursing, Taipei Medical University, Taipei, Taiwan
| | - Shih-Wei Huang
- are with the Department of Physical Medicine and Rehabilitation, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan.,are with the Department of Physical Medicine and Rehabilitation, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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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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Balci Yuce H, Akbulut N, Ocakli S, Kayir O, Elmastas M. The effect of commercial conjugated linoleic acid products on experimental periodontitis and diabetes mellitus in Wistar rats. Acta Odontol Scand 2017; 75:21-29. [PMID: 27897090 DOI: 10.1080/00016357.2016.1244355] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE The aim of present study was to determine the effects of conjugated linoleic acid enriched milk on alveolar bone loss, hyperglycaemia, oxidative stress and apoptosis in ligature-induced periodontal disease in diabetic rat model. METHODS Wistar rats were divided into six experimental groups: 1; non-ligated (NL, n = 6) group, 2; ligature only (LO, n = 6) group, 3; streptozotocin only (STZ, n = 8) group, 4; STZ and ligature (STZ + L, n = 8) group, 5; ligature and conjugated linoleic acid (CLA) (L + CLA, n = 8) group, 6; STZ, ligature and CLA group (STZ + L + CLA, n = 8) group. Diabetes mellitus was induced by 60 mg/kg streptozotocin. Rats were fed with CLA enriched milk for four weeks. Silk ligatures were placed at the gingival margin of lower first molars of mandibular quadrant. The study duration was four weeks after diabetes induction and the animals were sacrificed at the end of this period. Changes in alveolar bone levels were clinically measured and tissues were histopathologically examined. Inducible nitric oxide synthase (iNOS) and Bax protein expressions, serum interleukin-1β (IL-1β), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglyceride levels and tartrate resistant acid phosphatase (TRAP)+ osteoclast numbers were also evaluated. RESULTS At the end of four weeks, alveolar bone loss was significantly higher in the STZ + LO group compared to the other groups (p < .05). CLA decreased alveolar bone loss in L + CLA and STZ + L + CLA groups. CLA significantly decreased TRAP + osteoclast numbers and increased osteoblastic activity compared to the STZ + L group (p < .05). Diabetes and CLA increased Bax protein levels (p < .05) however CLA had no effect on iNOS expression (p > .05). CONCLUSION Within the limits of this study, commercial CLA product administration in addition to diet significantly reduced alveolar bone loss, increased osteoblastic activity and decreased osteoclastic activity in the diabetic Wistar rats.
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PINA FLC, RIBEIRO AS, DODERO SR, BARBOSA DS, CYRINO ES, TIRAPEGUI J. Conjugated linoleic acid supplementation does not maximize motor performance and abdominal and trunk fat loss induced by aerobic training in overweight women. REV NUTR 2016. [DOI: 10.1590/1678-98652016000600004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ABSTRACT Objective: To analyze the effect of eight weeks of conjugated linoleic acid supplementation on physical performance, and trunk and abdominal fat in overweight women submitted to an aerobic training program. Methods: Twenty-eight overweight women (body mass index ³25 kg/m2) were divided randomly and double-blindly to receive conjugated linoleic acid or placebo, both associated with an aerobic exercise program (frequency = three times a week, duration=30 min/session, intensity=80% of maximum heart rate). Conjugated linoleic acid (3.2 g) and placebo (4.0 g) supplements were consumed daily (four capsules) for eight weeks. Maximum speed and time to exhaustion were determined in incremental treadmill test. Trunk fat was estimated by dual-energy X-Ray absorptiometry. Waist circumference was used as indicator of abdominal fat. Results: Main effect of time (p<0.05) showed increased maximum speed (conjugated linoleic acid=+6.3% vs. placebo=+7.5%) and time to exhaustion (conjugated linoleic acid=+7.1% vs. placebo=+8.6%) in the incremental treadmill test, with no differences between the groups (p>0.05). Similarly, significant reductions (p<0.05) in trunk fat (conjugated linoleic acid=-1.7% vs. placebo=-1.5%) and abdominal fat (conjugated linoleic acid=-4.7% vs. placebo=-4.0%) were found after eight weeks of intervention, with no differences between the groups (p>0.05). Conclusion: The results of this study suggest that conjugated linoleic acid supplementation does not maximize motor performance, and loss of body and abdominal fat induced by aerobic training in overweight women.
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Yang SQ, DeGuire JR, Lavery P, Mak IL, Weiler HA, Santosa S. Conjugated linoleic acid mitigates testosterone-related changes in body composition in male guinea pigs. Nutr Res 2016; 36:408-17. [PMID: 27101759 DOI: 10.1016/j.nutres.2015.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 12/14/2015] [Accepted: 12/23/2015] [Indexed: 11/24/2022]
Abstract
We hypothesize that conjugated linoleic acid (CLA) may be effective in preventing the changes in total and regional body composition and increases in interleukin (IL) 6 that occur as a result of hypogonadism. Male guinea pigs (n = 40, 70- to 72-week retired breeders) were block randomized by weight into 4 groups: (1) sham surgery (SHAM)/control (CTRL) diet, (2) SHAM/conjugated linoleic acid (CLA) diet (1%), (3) orchidectomy (ORX)/CTRL diet, and (4) ORX/CLA diet. Dual-energy x-ray absorptiometry scans were performed at baseline and week 16 to assess body composition. Serum IL-6 was analyzed using an enzyme-linked immune sorbent assay. Fatty acids (FAs) from visceral and subcutaneous adipose tissue were analyzed using gas chromatography. In ORX/CTRL guinea pigs, percent total body fat increased by 6.1%, and percent lean mass decreased by 6.7% over the 16-week treatment period, whereas no changes were observed for either parameter in ORX/CLA guinea pigs. Guinea pigs fed the CLA diet gained less percent total, upper, and lower body fat than those fed the CTRL diet regardless of surgical treatment. Regional adipose tissue FA composition was reflective of dietary FAs. Serum IL-6 concentrations were not different among groups. In this study, we observed that, in male guinea pigs, hypogonadism resulted in increased fat mass and decreased lean mass. In addition, CLA was effective in reducing gains in body fat and maintaining lean mass in both hypogonadal and intact guinea pigs.
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Affiliation(s)
- Susan Q Yang
- School of Dietetics and Human Nutrition, McGill University, Montreal, QC H9X 3V9, Canada
| | - Jason R DeGuire
- School of Dietetics and Human Nutrition, McGill University, Montreal, QC H9X 3V9, Canada
| | - Paula Lavery
- School of Dietetics and Human Nutrition, McGill University, Montreal, QC H9X 3V9, Canada
| | - Ivy L Mak
- School of Dietetics and Human Nutrition, McGill University, Montreal, QC H9X 3V9, Canada
| | - Hope A Weiler
- School of Dietetics and Human Nutrition, McGill University, Montreal, QC H9X 3V9, Canada
| | - Sylvia Santosa
- Department of Exercise Science, Concordia University, Montreal, QC H4B 1R6, Canada; Nutrition, Obesity and Metabolism Lab, PERFORM Centre, Concordia University, Montreal, QC H4B 1R6, Canada.
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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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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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Tsao JP, Liao SF, Korivi M, Hou CW, Kuo CH, Wang HF, Cheng IS. Oral conjugated linoleic acid supplementation enhanced glycogen resynthesis in exercised human skeletal muscle. J Sports Sci 2014; 33:915-23. [DOI: 10.1080/02640414.2014.970219] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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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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