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Gheysari R, Nikbaf-Shandiz M, Hosseini AM, Rasaei N, Hosseini S, Bahari H, Asbaghi O, Rastgoo S, Goudarzi K, Shiraseb F, Behmadi R. The effects of L-carnitine supplementation on cardiovascular risk factors in participants with impaired glucose tolerance and diabetes: a systematic review and dose-response meta-analysis. Diabetol Metab Syndr 2024; 16:185. [PMID: 39085907 PMCID: PMC11290177 DOI: 10.1186/s13098-024-01415-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 07/16/2024] [Indexed: 08/02/2024] Open
Abstract
AIMS L-carnitine plays a role related to cardiometabolic factors, but its effectiveness and safety in CVD are still unknown. We aim to assess the effect of L-carnitine supplementation on CVD risk factors. METHODS A systematic literature search was conducted in PubMed, Web of Science, and Scopus until October 2022. The main outcomes were lipid profiles, anthropometric parameters, insulin resistance, serum glucose levels, leptin, blood pressure, and inflammatory markers. The pooled weighted mean difference (WMD) was calculated using a random-effects model. RESULTS We included the 21 RCTs (n = 2900) with 21 effect sizes in this study. L-carnitine supplementation had a significant effect on TG (WMD = - 13.50 mg/dl, p = 0.039), LDL (WMD = - 12.66 mg/dl, p < 0.001), FBG (WMD = - 6.24 mg/dl, p = 0.001), HbA1c (WMD = -0.37%, p = 0.013) HOMA-IR (WMD = -0.72, p = 0.038 (, CRP (WMD = - 0.07 mg/dl, P = 0.037), TNF-α (WMD = - 1.39 pg/ml, p = 0.033), weight (WMD = - 1.58 kg, p = 0.001 (, BMI (WMD = - 0.28 kg/m2, p = 0.017(, BFP (WMD = - 1.83, p < 0.001) and leptin (WMD = - 2.21 ng/ml, p = 0.003 (in intervention, compared to the placebo group, in the pooled analysis. CONCLUSIONS This meta-analysis demonstrated that administration of L-carnitine in diabetic and glucose intolerance patients can significantly reduce TG, LDL-C, FBG, HbA1c, HOMA-IR, CRP, TNF-α, weight, BMI, BFP, and leptin levels. PROSPERO registration code: CRD42022366992.
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Affiliation(s)
- Rezvan Gheysari
- Shohada-E-Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Amir Mehdi Hosseini
- Faculty of Medical Sciences and Technologies, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Niloufar Rasaei
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Shabnam Hosseini
- School of Human Nutrition, Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, QC, Canada
| | - Hossein Bahari
- Transplant Research Center, Clinical Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Omid Asbaghi
- Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - 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
| | - Kian Goudarzi
- Faculty of Medicine, 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.
| | - Reza Behmadi
- Department of Pediatrics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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Mirrafiei A, Jayedi A, Shab-Bidar S. The Effects of L-Carnitine Supplementation on Weight Loss, Glycemic Control, and Cardiovascular Risk Factors in Patients With Type 2 Diabetes: A Systematic Review and Dose-response Meta-Analysis of Randomized Controlled Trials. Clin Ther 2024; 46:404-410. [PMID: 38594107 DOI: 10.1016/j.clinthera.2024.03.002] [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] [Received: 04/05/2023] [Revised: 12/28/2023] [Accepted: 03/12/2024] [Indexed: 04/11/2024]
Abstract
PURPOSE L-carnitine supplementation has been recommended to improve cardiometabolic health markers in diabetic patients. Our purpose was to assess the dose-dependent effects of l-carnitine supplementation on cardiometabolic risk factors in patients with type 2 diabetes. METHODS PubMed/Medline, Scopus, and Web of Science were searched until May 2022 for randomized controlled trials that examined the impact of l-carnitine supplementation on cardiometabolic risk factors in adults with type 2 diabetes. The mean difference (MD) and its 95% confidence interval (CI) were estimated utilizing a random-effects model. Nonlinear dose-response associations were modeled with restricted cubic splines. The certainty of evidence was rated using the GRADE approach. FINDINGS Twenty-one randomized trials with 2041 patients with type 2 diabetes were included. We found that every 1 g/d supplementation with l-carnitine significantly reduced body mass index (MD: -0.37 kg/m2, 95% CI: -0.59, -0.15; I2 =93%, n=13, GRADE=low), HbA1c (MD: -0.16%, 95% CI: -0.32, -0.01; I2 = 94%, n = 18, GRADE = moderate), and low-density lipoprotein cholesterol (MD: -0.11 mmol/L, 95% CI: -0.16, -0.05; I2 = 91%, n = 11, GRADE = high). There were also reductions in serum triglycerides (MD: 0.07 mmol/L), total cholesterol (MD: -0.13 mmol/L), and fasting plasma glucose (MD: -0.17 mmol/L). A U-shaped effect was demonstrated for body mass index, with the largest reduction at 2 g/d. A linear reduction was seen for serum triglycerides, total cholesterol, and fasting plasma glucose up to l-carnitine supplementation of 4 g/d. IMPLICATIONS L-carnitine supplementation resulted in a small reduction in serum lipids and plasma glucose in patients with type 2 diabetes. However, due to high statistical heterogeneity, the results should be interpreted very cautiously.
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Affiliation(s)
- Amin Mirrafiei
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Ahmad Jayedi
- Social Determinant of Health Research Center, Semnan University of Medical Sciences, Semnan, Iran
| | - Sakineh Shab-Bidar
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Iran; Sports Medicine Research Center, Neuroscience Institute, Tehran University of Medical Sciences (TUMS), Tehran, Iran.
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Nofal AE, AboShabaan HS, Fadda WA, Ereba RE, Elsharkawy SM, Hathout HM. L-carnitine and Ginkgo biloba Supplementation In Vivo Ameliorates HCD-Induced Steatohepatitis and Dyslipidemia by Regulating Hepatic Metabolism. Cells 2024; 13:732. [PMID: 38727268 PMCID: PMC11083725 DOI: 10.3390/cells13090732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/16/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024] Open
Abstract
Treatment strategies for steatohepatitis are of special interest given the high prevalence of obesity and fatty liver disease worldwide. This study aimed to investigate the potential therapeutic mechanism of L-carnitine (LC) and Ginkgo biloba leaf extract (GB) supplementation in ameliorating the adverse effects of hyperlipidemia and hepatosteatosis induced by a high-cholesterol diet (HCD) in an animal model. The study involved 50 rats divided into five groups, including a control group, a group receiving only an HCD, and three groups receiving an HCD along with either LC (300 mg LC/kg bw), GB (100 mg GB/kg bw), or both. After eight weeks, various parameters related to lipid and glucose metabolism, antioxidant capacity, histopathology, immune reactivity, and liver ultrastructure were measured. LC + GB supplementation reduced serum total cholesterol, triglyceride, low-density lipoprotein cholesterol, glucose, insulin, HOMA-IR, alanine transaminase, and aspartate transaminase levels and increased high-density lipoprotein cholesterol levels compared with those in the HCD group. Additionally, treatment with both supplements improved antioxidant ability and reduced lipid peroxidation. The histological examination confirmed that the combination therapy reduced liver steatosis and fibrosis while also improving the appearance of cell organelles in the ultrastructural hepatocytes. Finally, the immunohistochemical analysis indicated that cotreatment with LC + GB upregulated the immune expression of GLP-1 and β-Cat in liver sections that were similar to those of the control animals. Mono-treatment with LC or GB alone substantially but not completely protected the liver tissue, while the combined use of LC and GB may be more effective in treating liver damage caused by high cholesterol than either supplement alone by regulating hepatic oxidative stress and the protein expression of GLP-1 and β-Cat.
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Affiliation(s)
- Amany E. Nofal
- Zoology Department, Faculty of Science, Menoufia University, Shebin El-Kom 32511, Egypt;
| | - Hind S. AboShabaan
- Clinical Pathology Department, National Liver Institute Hospital, Menoufia University, Shebin El-Kom 32511, Egypt;
| | - Walaa A. Fadda
- Human Anatomy and Embryology Department, Faculty of Medicine, Menoufia University, Shebin El-Kom 32511, Egypt;
| | - Rafik E. Ereba
- Department of Pharmacology, Faculty of Medicine, Al-Azhar University, Cario 11511, Egypt;
| | | | - Heba M. Hathout
- Natural Resources Department, Faculty of African Postgraduate Studies, Cairo University, Giza 12613, Egypt
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Anaraki SR, Aali Y, Nikbaf-Shandiz M, Rasaei N, Khadem A, Bahari H, Khalse Z, Rastgoo S, Shiraseb F, Asbaghi O. The Effects of L-Carnitine Supplementation on Blood Pressure in Adults: A Systematic Review and Dose-response Meta-analysis. Clin Ther 2024; 46:e73-e86. [PMID: 38101999 DOI: 10.1016/j.clinthera.2023.11.002] [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] [Received: 08/24/2023] [Revised: 10/25/2023] [Accepted: 11/05/2023] [Indexed: 12/17/2023]
Abstract
PURPOSE Hypertension stands as a prominent risk factor for cardiovascular disease, making it of utmost importance to address. Studies have shown that L-carnitine supplementation may lower blood pressure (BP) parameters in different populations. Therefore, we have conducted a systematic review and dose-response meta-analysis of published Randomized Controlled Trials (RCTs), including the most recent articles on the effect of L-carnitine supplementation on BP. METHODS PubMed, ISI Web of Science, Cochrane databases, and Scopus were used to collect RCT studies published up to October 2022 without limitations in language. Inclusion criteria were adult participants and recipients of L-carnitine in oral supplemental forms. The funnel plot test, Begg's test, and Egger's test were used to examine publication bias. FINDINGS After the search strategy, 22 RCTs (n = 1412) with 24 effect sizes fulfilled the criteria. It was found L-Carnitine supplementation did not have a significant effect on systolic blood pressure (SBP) (mm Hg) (weighted mean difference [WMD] = -1.22 mm Hg, 95% CI: -3.79, 1.35; P = 0.352; I2 = 85.0%, P < 0.001), and diastolic blood pressure (mm Hg) (WMD = -0.50 mm Hg, 95% CI: -1.49, 0.48; P = 0.318; I2 = 43.4%, P = 0.021) in the pooled analysis. Subgroup analyses have shown that L-carnitine supplementation had no lowering effect on SBP in any subgroup. However, there was a significant reduction in diastolic blood pressure in participants with a baseline body mass index >30 kg/m2 (WMD = -1.59 mm Hg; 95% CI: -3.11, -0.06; P = 0.041; I2 = 41.3%, P = 0.164). There was a significant nonlinear relationship between the duration of L-carnitine intervention and changes in SBP (coefficients = -6.83, P = 0.045). IMPLICATIONS L-carnitine supplementation in adults did not significantly affect BP. But anyway, more studies should be done in this field on different individuals.
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Affiliation(s)
| | - Yasaman Aali
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | | | - Niloufar Rasaei
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Iran; Network of Interdisciplinarity in Neonates and Infants (NINI), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - Alireza Khadem
- Department of Nutrition, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Hossein Bahari
- Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zeinab Khalse
- Department of Pharmacy, Faculty of Pharmacy, University of Tehran, Tehran, Iran
| | - Samira Rastgoo
- Department of Cellular and Molecular Nutrition, National Nutrition and Food Technology Research Institute, Faculty of Nutrition Science and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Student Research Committee, 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
| | - Omid Asbaghi
- Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Zamani M, Pahlavani N, Nikbaf-Shandiz M, Rasaei N, Ghaffarian-Ensaf R, Asbaghi O, Shiraseb F, Rastgoo S. The effects of L-carnitine supplementation on glycemic markers in adults: A systematic review and dose-response meta-analysis. Front Nutr 2023; 9:1082097. [PMID: 36704801 PMCID: PMC9871499 DOI: 10.3389/fnut.2022.1082097] [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: 10/27/2022] [Accepted: 12/21/2022] [Indexed: 01/11/2023] Open
Abstract
Background and aims Hyperglycemia and insulin resistance are concerns today worldwide. Recently, L-carnitine supplementation has been suggested as an effective adjunctive therapy in glycemic control. Therefore, it seems important to investigate its effect on glycemic markers. Methods PubMed, Scopus, Web of Science, and the Cochrane databases were searched in October 2022 for prospective studies on the effects of L-carnitine supplementation on glycemic markers. Inclusion criteria included adult participants and taking oral L-carnitine supplements for at least seven days. The pooled weighted mean difference (WMD) was calculated using a random-effects model. Results We included the 41 randomized controlled trials (RCTs) (n = 2900) with 44 effect sizes in this study. In the pooled analysis; L-carnitine supplementation had a significant effect on fasting blood glucose (FBG) (mg/dl) [WMD = -3.22 mg/dl; 95% CI, -5.21 to -1.23; p = 0.002; I 2 = 88.6%, p < 0.001], hemoglobin A1c (HbA1c) (%) [WMD = -0.27%; 95% CI, -0.47 to -0.07; p = 0.007; I 2 = 90.1%, p < 0.001] and homeostasis model assessment-estimate insulin resistance (HOMA-IR) [WMD = -0.73; 95% CI, -1.21 to -0.25; p = 0.003; I 2 = 98.2%, p < 0.001] in the intervention compared to the control group. L-carnitine supplementation had a reducing effect on baseline FBG ≥100 mg/dl, trial duration ≥12 weeks, intervention dose ≥2 g/day, participants with overweight and obesity (baseline BMI 25-29.9 and >30 kg/m2), and diabetic patients. Also, L-carnitine significantly affected insulin (pmol/l), HOMA-IR (%), and HbA1c (%) in trial duration ≥12 weeks, intervention dose ≥2 g/day, and participants with obesity (baseline BMI >30 kg/m2). It also had a reducing effect on HOMA-IR in diabetic patients, non-diabetic patients, and just diabetic patients for insulin, and HbA1c. There was a significant nonlinear relationship between the duration of intervention and changes in FBG, HbA1c, and HOMA-IR. In addition, there was a significant nonlinear relationship between dose (≥2 g/day) and changes in insulin, as well as a significant linear relationship between the duration (weeks) (coefficients = -16.45, p = 0.004) of intervention and changes in HbA1C. Conclusions L-carnitine could reduce the levels of FBG, HbA1c, and HOMA-IR. Systematic review registration https://www.crd.york.ac.uk/prospero/, identifier: CRD42022358692.
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Affiliation(s)
- Mohammad Zamani
- 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,Behbahan Faculty of Medical Sciences, Behbahan, Iran
| | | | - Niloufar Rasaei
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | | | - Omid Asbaghi
- Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran,Student Research Committee, 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,*Correspondence: Farideh Shiraseb ✉
| | - 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,Samira Rastgoo ✉
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KIANI AYSHAKARIM, BONETTI GABRIELE, MEDORI MARIACHIARA, CARUSO PAOLA, MANGANOTTI PAOLO, FIORETTI FRANCESCO, NODARI SAVINA, CONNELLY STEPHENTHADDEUS, BERTELLI MATTEO. Dietary supplements for improving nitric-oxide synthesis. JOURNAL OF PREVENTIVE MEDICINE AND HYGIENE 2022; 63:E239-E245. [PMID: 36479475 PMCID: PMC9710401 DOI: 10.15167/2421-4248/jpmh2022.63.2s3.2766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Nitric oxide (NO) is an essential component of the human body, involved in blood vessel dilation, stimulation of hormone release, signaling and regulation of neurotransmission. Nitric oxide is synthesized by nitric-oxide-synthase-dependent and -independent pathways. Nitric oxide supplementation improves cardiac health, enhances performance during exercise, reduces high blood pressure during pregnancy, reduces erectile dysfunction and improves healing processes and respiratory response. Nitric-oxide-associated benefits are mostly apparent in untrained or moderately trained individuals. L-arginine and L-citrulline supplementation contributes to nitric oxide levels because L-arginine is directly involved in NO synthesis, whereas L-citrulline acts as an L-arginine precursor that is further converted to NO by a reaction catalyzed by NO synthase. L-arginine supplements increase respiratory response and enhance performance during exercise, while L-citrulline with malate and other molecules increase working capacity. Various studies involving beetroot juice have reported a significant increase in plasma nitrite levels, regarded as markers of NO, after intake of beetroot juice. Although NO supplementation may have mild to moderate side-effects, using smaller or divided doses could avoid some of these side-effects. Since nitric oxide supplementation may worsen certain health conditions and may interfere with certain medicines, it should only be taken under medical supervision.
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Affiliation(s)
| | - GABRIELE BONETTI
- MAGI’S LAB, Rovereto (TN), Italy
- Correspondence: Gabriele Bonetti, MAGI’S LAB, Rovereto (TN), 38068, Italy. E-mail:
| | | | - PAOLA CARUSO
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, Cattinara University Hospital ASUGI, University of Trieste, Trieste, Italy
| | - PAOLO MANGANOTTI
- Clinical Unit of Neurology, Department of Medicine, Surgery and Health Sciences, Cattinara University Hospital ASUGI, University of Trieste, Trieste, Italy
| | - FRANCESCO FIORETTI
- Department of Cardiology, University of Brescia and ASST “Spedali Civili” Hospital, Brescia, Italy
| | - SAVINA NODARI
- Department of Cardiology, University of Brescia and ASST “Spedali Civili” Hospital, Brescia, Italy
| | | | - MATTEO BERTELLI
- MAGI Euregio, Bolzano, Italy
- MAGI’S LAB, Rovereto (TN), Italy
- MAGISNAT, Peachtree Corners (GA), USA
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Acetyl-L-Carnitine Ameliorates Metabolic and Endocrine Alterations in Women with PCOS: A Double-Blind Randomized Clinical Trial. Adv Ther 2021; 38:3842-3856. [PMID: 34047916 DOI: 10.1007/s12325-021-01789-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/13/2021] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Polycystic ovary syndrome (PCOS) is a common endocrine-metabolic disorder and the main cause of infertility in women of reproductive age. Affected women suffer from insulin resistance and present with an intense stress response. Treatment with insulin sensitizers alone and in combination is used to ameliorate the signs and symptoms associated with the disease. This study was designed to compare the endocrine and metabolic parameters as well as subjective and objective measures of stress in women with PCOS before and after treatment with acetyl-L-carnitine (ALC) and metformin plus pioglitazone. METHODS A total of 147 women with PCOS were randomly assigned into two groups: the combo group (n = 72) received a combination of metformin, pioglitazone, and ALC (500 mg, 15 mg, and 1500 mg, respectively), twice daily; the Met + Pio group (n = 75) received metformin plus pioglitazone (500 mg, 15 mg, respectively) and placebo (citric acid plus calcium carbonate), twice daily for 12 weeks. Medications were discontinued when pregnancy was confirmed. The Perceived Stress Scale (PSS14) and Profile of Mood States (POMS) were employed as subjective measures of stress. The endocrine and metabolic functions of women with PCOS were assessed by measuring insulin, leutinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, and adiponectin levels in fasting blood samples. Insulin resistance was calculated by Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). RESULTS Women at baseline had significantly elevated circulating concentration of insulin and low level of adiponectin. Treatment decreased insulin in both groups; however, the combo group showed a significant decrease (p = 0.001). Serum adiponectin level was raised significantly after treatment in both groups (p < 0.001). HOMA-IR also decreased in both groups (both p < 0.001). Testosterone, FSH, and LH significantly improved in both groups. LH also decreased in both groups; however, the change was significant only in the combo (metformin plus pioglitazone plus ALC) group (p = 0.013). Interestingly, there was a significant improvement in body circumference (p < 0.001) in the combo group. The PSS scores of the patients improved significantly (p < 0.001) in the combo group. Interestingly, regular menstrual cycles were found (97.2%) in the carnitine group, but in only 12.9% of the other group. CONCLUSION We conclude that addition of ALC therapy is superior to metformin plus pioglitazone in ameliorating insulin resistance, polycystic ovaries, menstrual irregularities, and hypoadiponectinemia in women with PCOS. TRIAL REGISTRATION Trial registration: clinicalTrial.gov NCT04113889. Registered 3 October, 2019. https://clinicaltrials.gov/ct2/show/NCT04113889 .
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Fathizadeh H, Milajerdi A, Reiner Ž, Amirani E, Asemi Z, Mansournia MA, Hallajzadeh J. The effects of L-carnitine supplementation on indicators of inflammation and oxidative stress: a systematic review and meta-analysis of randomized controlled trials. J Diabetes Metab Disord 2020; 19:1879-1894. [PMID: 33520867 DOI: 10.1007/s40200-020-00627-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 08/27/2020] [Accepted: 08/31/2020] [Indexed: 02/07/2023]
Abstract
Objective Several trials investigated the efficacy of L-carnitine administration on markers of inflammation and indicators of oxidative stress; however, their findings are controversial. The aim of this study was to conduct a comprehensive meta-analysis and a critical review, which would analyze all randomized controlled trials (RCTs) in order to determine the effects of L-carnitine supplementation on inflammatory markers and oxidative stress. Methods An electronic search was performed using Scopus, Cochrane Library, PubMed, Google scholar and Web of Science databases on publications from 1990 up to May 2020. Human RCTs conducted in healthy subjects or participants with certain disorders which investigating the efficacy of L-carnitine supplementation compared to control (placebo, usual treatment or no intervention) on inflammation and oxidative markers were included. Data were pooled applying a random-effects model and as the overall effect size, weighted mean difference (WMD) was presented. Between heterogeneity among studies was computed using Cochran's Q test and I-square (I2). Quality of studies assessed using the Jadad scale. Dose-response analysis was measured using meta-regression. The funnel plot, as well as the Egger's regression test was applied to determine the publication bias. Results 44 trials (reported 49 effect sizes for different outcomes of interest) met the inclusion criteria for this meta-analysis. According to the findings, L-carnitine supplementation resulted in a significant reduction in C-reactive protein (CRP) (WMD: -0.10; 95% CI: -0.14, -0.06), interleukin 6 (IL-6) (WMD: -1.87; 95% CI: -2.80, -0.95), tumor necrosis factor-α (TNF-α) levels (WMD: -1.43; 95% CI: -2.03, -0.84), and malondialdehyde (MDA) (WMD: -0.47; 95% CI: -0.76, -0.18) levels, while there was a significant increase in superoxide dismutase (SOD) (WMD: 2.14; 95% CI: 1.02, 3.25). However, no significant effects of L-carnitine on glutathione peroxidase (GPx) (WMD: 0.02; 95% CI: -0.01, 0.05) and total antioxidant capacity (TAC) (WMD: 0.14; 95% CI: -0.05, 0.33) were found. Conclusions L-carnitine supplementation was associated with lowering of CRP, IL-6, TNF-α, and MDA, and increasing SOD levels, but did not affect other inflammatory and oxidative stress biomarkers.
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Affiliation(s)
- Hadis Fathizadeh
- Department of Microbiology, Kashan University of Medical Sciences, Kashan, Islamic Republic of Iran
| | - Alireza Milajerdi
- Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Željko Reiner
- Department of Internal Medicine, University Hospital Centre Zagreb, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Elaheh Amirani
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Islamic Republic of Iran
| | - Zatollah Asemi
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Islamic Republic of Iran
| | - Mohammad Ali Mansournia
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Jamal Hallajzadeh
- Department of Biochemistry and Nutrition, Research Center for Evidence-Based Health Management, Maragheh University of Medical Sciences, Maragheh, Iran
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Kepka A, Ochocinska A, Borzym-Kluczyk M, Skorupa E, Stasiewicz-Jarocka B, Chojnowska S, Waszkiewicz N. Preventive Role of L-Carnitine and Balanced Diet in Alzheimer's Disease. Nutrients 2020; 12:E1987. [PMID: 32635400 PMCID: PMC7400709 DOI: 10.3390/nu12071987] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/25/2020] [Accepted: 06/29/2020] [Indexed: 02/06/2023] Open
Abstract
The prevention or alleviation of neurodegenerative diseases, including Alzheimer's disease (AD), is a challenge for contemporary health services. The aim of this study was to review the literature on the prevention or alleviation of AD by introducing an appropriate carnitine-rich diet, dietary carnitine supplements and the MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) diet, which contains elements of the Mediterranean diet and the Dietary Approaches to Stop Hypertension (DASH) diet. L-carnitine (LC) plays a crucial role in the energetic metabolism of the cell. A properly balanced diet contains a substantial amount of LC as well as essential amino acids and microelements taking part in endogenous carnitine synthesis. In healthy people, carnitine biosynthesis is sufficient to prevent the symptoms of carnitine deficiency. In persons with dysfunction of mitochondria, e.g., with AD connected with extensive degeneration of the brain structures, there are often serious disturbances in the functioning of the whole organism. The Mediterranean diet is characterized by a high consumption of fruits and vegetables, cereals, nuts, olive oil, and seeds as the major source of fats, moderate consumption of fish and poultry, low to moderate consumption of dairy products and alcohol, and low intake of red and processed meat. The introduction of foodstuffs rich in carnitine and the MIND diet or carnitine supplementation of the AD patients may improve their functioning in everyday life.
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Affiliation(s)
- Alina Kepka
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
| | - Agnieszka Ochocinska
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
| | - Małgorzata Borzym-Kluczyk
- Department of Pharmaceutical Biochemistry, Medical University of Bialystok, 15-089 Bialystok, Poland;
| | - Ewa Skorupa
- Department of Biochemistry, Radioimmunology and Experimental Medicine, The Children’s Memorial Health Institute, 04-730 Warsaw, Poland;
| | | | - Sylwia Chojnowska
- Faculty of Health Sciences, Lomza State University of Applied Sciences, 18-400 Lomza, Poland;
| | - Napoleon Waszkiewicz
- Department of Psychiatry, Medical University of Bialystok, 15-089 Bialystok, Poland;
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Talenezhad N, Mohammadi M, Ramezani-Jolfaie N, Mozaffari-Khosravi H, Salehi-Abargouei A. Effects of l-carnitine supplementation on weight loss and body composition: A systematic review and meta-analysis of 37 randomized controlled clinical trials with dose-response analysis. Clin Nutr ESPEN 2020; 37:9-23. [DOI: 10.1016/j.clnesp.2020.03.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/31/2020] [Accepted: 03/10/2020] [Indexed: 02/06/2023]
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Reply - Letter to the Editor - Meta-analysis of L-carnitine supplementation on lipid profile and glycemic control: inadequate search strategy and other methodological issues. Clin Nutr 2020; 39:1977. [PMID: 32386859 DOI: 10.1016/j.clnu.2020.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 04/15/2020] [Indexed: 11/24/2022]
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Raeisi-Dehkordi H, Muka T. Meta-analysis of l-carnitine supplementation on lipid profile and glycemic control: Inadequate search strategy and other methodological issues. Clin Nutr 2020; 39:1975-1976. [PMID: 32386858 DOI: 10.1016/j.clnu.2020.04.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/15/2020] [Indexed: 10/24/2022]
Affiliation(s)
- Hamidreza Raeisi-Dehkordi
- Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran; Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran; Nutrition Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Taulant Muka
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland.
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ALSUntangled 53: Carnitine supplements. Amyotroph Lateral Scler Frontotemporal Degener 2020; 21:477-483. [PMID: 32046513 DOI: 10.1080/21678421.2020.1726565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Askarpour M, Hadi A, Miraghajani M, Symonds ME, Sheikhi A, Ghaedi E. Beneficial effects of l-carnitine supplementation for weight management in overweight and obese adults: An updated systematic review and dose-response meta-analysis of randomized controlled trials. Pharmacol Res 2020; 151:104554. [DOI: 10.1016/j.phrs.2019.104554] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 10/07/2019] [Accepted: 11/16/2019] [Indexed: 10/25/2022]
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Fathizadeh H, Milajerdi A, Reiner Ž, Kolahdooz F, Chamani M, Amirani E, Asemi Z. The Effects of L-Carnitine Supplementation on Serum Lipids: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Curr Pharm Des 2019; 25:3266-3281. [DOI: 10.2174/1381612825666190830154336] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/27/2019] [Indexed: 01/07/2023]
Abstract
Background:
The findings of trials investigating the effects of L-carnitine administration on serum
lipids are inconsistent. This meta-analysis of randomized controlled trials (RCTs) was performed to summarize
the effects of L-carnitine intake on serum lipids in patients and healthy individuals.
Methods:
Two authors independently searched electronic databases including MEDLINE, EMBASE, Cochrane
Library, Web of Science, PubMed and Google Scholar from 1990 until August 1, 2019, in order to find relevant
RCTs. The quality of selected RCTs was evaluated using the Cochrane Collaboration risk of bias tool. Cochrane’s
Q test and I-square (I2) statistic were used to determine the heterogeneity across included trials. Weight mean
difference (SMD) and 95% CI between the two intervention groups were used to determine pooled effect sizes.
Subgroup analyses were performed to evaluate the source of heterogeneity based on suspected variables such as,
participant’s health conditions, age, dosage of L-carnitine, duration of study, sample size, and study location
between primary RCTs.
Results:
Out of 3460 potential papers selected based on keywords search, 67 studies met the inclusion criteria and
were eligible for the meta-analysis. The pooled results indicated that L-carnitine administration led to a significant
decrease in triglycerides (WMD: -10.35; 95% CI: -16.43, -4.27), total cholesterol (WMD: -9.47; 95% CI: -
13.23, -5.70) and LDL-cholesterol (LDL-C) concentrations (WMD: -6.25; 95% CI: -9.30, -3.21), and a significant
increase in HDL-cholesterol (HDL-C) levels (WMD: 1.39; 95% CI: 0.21, 2.57). L-carnitine supplementation did
not influence VLDL-cholesterol concentrations. When we stratified studies for the predefined factors such as
dosage, and age, no significant effects of the intervention on triglycerides, LDL-C, and HDL-C levels were found.
Conclusion:
This meta-analysis demonstrated that L-carnitine administration significantly reduced triglycerides,
total cholesterol and LDL-cholesterol levels, and significantly increased HDL-cholesterol levels in the pooled
analyses, but did not affect VLDL-cholesterol levels; however, these findings were not confirmed in our subgroup
analyses by participant’s health conditions, age, dosage of L-carnitine, duration of study, sample size, and study
location.
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Affiliation(s)
- Hadis Fathizadeh
- Department of Microbiology and Immunology, Kashan University of Medical Sciences, Kashan, Iran
| | - Alireza Milajerdi
- Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Željko Reiner
- Department of Internal Medicine, University Hospital Centre Zagreb, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Fariba Kolahdooz
- Indigenous and Global Health Research, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Maryam Chamani
- Department of Gynecology and Obstetrics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Elaheh Amirani
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran
| | - Zatollah Asemi
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran
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Askarpour M, Hadi A, Symonds ME, Miraghajani M, Sheikhi A, Ghaedi E. Efficacy of l-carnitine supplementation for management of blood lipids: A systematic review and dose-response meta-analysis of randomized controlled trials. Nutr Metab Cardiovasc Dis 2019; 29:1151-1167. [PMID: 31561944 DOI: 10.1016/j.numecd.2019.07.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/04/2019] [Accepted: 07/16/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND AND AIM l-carnitine has an important role in fatty acid metabolism and could therefore act as an adjuvant agent in the improvement of dyslipidemia. The purpose of present systematic review and meta-analysis was to critically assess the efficacy of l-carnitine supplementation on lipid profiles. METHODS AND RESULTS We performed a systematic search of all available randomized controlled trials (RCTs) in the following databases: Scopus, PubMed, ISI Web of Science, The Cochrane Library. Mean difference (MD) of any effect was calculated using a random-effects model. In total, there were 55 eligible RCTs included with 58 arms, and meta-analysis revealed that l-carnitine supplementation significantly reduced total cholesterol (TC) (56 arms-MD: -8.53 mg/dl, 95% CI: -13.46, -3.6, I2: 93%), low-density lipoprotein-cholesterol (LDL-C) (47 arms-MD: -5.48 mg/dl, 95% CI: -8.49, -2.47, I2: 94.5) and triglyceride (TG) (56 arms-MD: -9.44 mg/dl, 95% CI: -16.02, -2.87, I2: 91.8). It also increased high density lipoprotein-cholesterol (HDL-C) (51 arms-MD:1.64 mg/dl, 95% CI:0.54, 2.75, I2: 92.2). l-carnitine supplementation reduced TC in non-linear fashion based on dosage (r = 21.11). Meta-regression analysis indicated a linear relationship between dose of l-carnitine and absolute change in TC (p = 0.029) and LDL-C (p = 0.013). Subgroup analyses showed that l-carnitine supplementation did not change TC, LDL-C and TG in patients under hemodialysis treatment. Intravenous l-carnitine and lower doses (>2 g/day) had no effect on TC, LDL-C and triglycerides. CONCLUSION l-carnitine supplementation at doses above 2 g/d has favorable effects on patients' lipid profiles, but is modulated on participant health and route of administration.
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Affiliation(s)
- Moein Askarpour
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Hadi
- Halal Research Center of IRI, FDA, Tehran, Iran; Food Security Research Center, Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Michael E Symonds
- The Early Life Research Unit, Academic Division of Child Health, Obstetrics and Gynaecology, and Nottingham Digestive Disease Centre and Biomedical Research Centre, The School of Medicine, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Maryam Miraghajani
- The Early Life Research Unit, Academic Division of Child Health, Obstetrics and Gynaecology, and Nottingham Digestive Disease Centre and Biomedical Research Centre, The School of Medicine, University of Nottingham, Nottingham, NG7 2UH, UK; Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Sheikhi
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Ehsan Ghaedi
- Students' Scientific Research Center (SSRC), Tehran University of Medical Sciences (TUMS), Tehran, Iran; Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
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Fathizadeh H, Milajerdi A, Reiner Ž, Kolahdooz F, Asemi Z. The effects of L-carnitine supplementation on glycemic control: a systematic review and meta-analysis of randomized controlled trials. EXCLI JOURNAL 2019; 18:631-643. [PMID: 31611746 PMCID: PMC6785772 DOI: 10.17179/excli2019-1447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/03/2019] [Indexed: 12/12/2022]
Abstract
The findings of trials investigating the effect of L-carnitine administration on glycemic control are controversial. This meta-analysis of randomized controlled trials (RCTs) was performed to explore the effects of L-carnitine intake on glycemic control. Two authors independently searched electronic databases including MEDLINE, EMBASE, Cochrane Library, Web of Science, PubMed and Google scholar from 1990 until February 2019, in order to find relevant RCTs. 37 studies with 44 effect sizes met the inclusion criteria and were eligible for the meta-analysis. L-carnitine supplementation resulted in a significant reduction in fasting plasma glucose (FPG) (WMD: -4.57; 95 % CI: -6.88, -2.25), insulin (WMD: -1.21; 95 % CI: -1.85, -0.57), homeostatic model assessment for insulin resistance (HOMA-IR) (WMD: -0.67; 95 % CI: -0.90, -0.44) and HbA1C concentrations (WMD: -0.30; 95 % CI: -0.47, -0.13). L-Carnitine supplementation significantly reduced FPG, insulin, HOMA-IR, and HbA1c levels.
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Affiliation(s)
- Hadis Fathizadeh
- Department of Microbiology, Kashan University of Medical Sciences, Kashan, Iran
| | - Alireza Milajerdi
- Students' Scientific Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Željko Reiner
- Department of Internal Medicine, University Hospital Centre Zagreb, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Fariba Kolahdooz
- Indigenous and Global Health Research, Department of Medicine, University of Alberta, Edmonton, Canada
| | - Zatollah Asemi
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, Iran
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The effect of L-carnitine on inflammatory mediators: a systematic review and meta-analysis of randomized clinical trials. Eur J Clin Pharmacol 2019; 75:1037-1046. [PMID: 30915521 DOI: 10.1007/s00228-019-02666-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 03/07/2019] [Indexed: 12/28/2022]
Abstract
AIM AND BACKGROUND Reducing inflammation by nutritional supplements may help to reduce the risk of many chronic diseases. Our aim in this meta-analysis was to determine the effect of L-carnitine on inflammatory mediators including C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6). METHODS Our systematic search to find relevant randomized clinical trials (RCTs) was performed up to October 2018 using ISI Web of Science, Google Scholar, PubMed/Medline, and SCOPUS. In this meta-analysis, the weighted mean differences (WMD) with standard errors (SE) were used to pool the data. WMD was calculated by subtracting change-from-baseline mean values in the control group from change-from-baseline mean values in the intervention group in each study. To identify heterogeneity among studies, the I2 statistic was employed. The protocol was registered with PROSPERO (No. CRD42019116695). RESULTS Thirteen articles were included in our systematic review and meta-analysis. The results of the meta-analysis indicated that L-carnitine supplementation was significantly associated with lower levels of CRP in comparison to controls (WMD = -1.23 mg/L; 95% CI: -1.73, -0.72 mg/dL; P < 0.0001). Also, a slight but statistically significant decrease was observed in IL-6 and TNF-α levels (WMD = -0.85 pg/dL; 95% CI: -1.38, -0.32 pg/dL; P = 0.002 and WMD = -0.37 pg/dL; 95% CI: -0.68, -0.06 pg/dL; P = 0.018, respectively). CONCLUSION Our results indicate that L-carnitine reduced inflammatory mediators, especially in studies with a duration of more than 12 weeks. Further studies with different doses and intervention durations and separately in men and women are necessary.
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Adeva-Andany MM, Calvo-Castro I, Fernández-Fernández C, Donapetry-García C, Pedre-Piñeiro AM. Significance of l-carnitine for human health. IUBMB Life 2017; 69:578-594. [PMID: 28653367 DOI: 10.1002/iub.1646] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 05/24/2017] [Indexed: 12/29/2022]
Abstract
Carnitine acyltransferases catalyze the reversible transfer of acyl groups from acyl-coenzyme A esters to l-carnitine, forming acyl-carnitine esters that may be transported across cell membranes. l-Carnitine is a wáter-soluble compound that humans may obtain both by food ingestion and endogenous synthesis from trimethyl-lysine. Most l-carnitine is intracellular, being present predominantly in liver, skeletal muscle, heart and kidney. The organic cation transporter-2 facilitates l-carnitine uptake inside cells. Congenital dysfunction of this transporter causes primary l-carnitine deficiency. Carnitine acetyltransferase is involved in the export of excess acetyl groups from the mitochondria and in acetylation reactions that regulate gene transcription and enzyme activity. Carnitine octanoyltransferase is a peroxysomal enzyme required for the complete oxidation of very long-chain fatty acids and phytanic acid, a branched-chain fatty acid. Carnitine palmitoyltransferase-1 is a transmembrane protein located on the outer mitochondrial membrane where it catalyzes the conversion of acyl-coenzyme A esters to acyl-carnitine esters. Carnitine acyl-carnitine translocase transports acyl-carnitine esters across the inner mitochondrial membrane in exchange for free l-carnitine that exits the mitochondrial matrix. Carnitine palmitoyltransferase-2 is anchored on the matrix side of the inner mitochondrial membrane, where it converts acyl-carnitine esters back to acyl-coenzyme A esters, which may be used in metabolic pathways, such as mitochondrial β-oxidation. l-Carnitine enhances nonoxidative glucose disposal under euglycemic hyperinsulinemic conditions in both healthy individuals and patients with type 2 diabetes, suggesting that l-carnitine strengthens insulin effect on glycogen storage. The plasma level of acyl-carnitine esters, primarily acetyl-carnitine, increases during diabetic ketoacidosis, fasting, and physical activity, particularly high-intensity exercise. Plasma concentration of free l-carnitine decreases simultaneously under these conditions. © 2017 IUBMB Life, 69(8):578-594, 2017.
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Su CC, Chang CS, Chou CH, Wu YHS, Yang KT, Tseng JK, Chang YY, Chen YC. L-carnitine ameliorates dyslipidemic and hepatic disorders induced by a high-fat diet via regulating lipid metabolism, self-antioxidant capacity, and inflammatory response. J Funct Foods 2015. [DOI: 10.1016/j.jff.2015.04.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Jain S, Singh SN. Effect of L-carnitine Supplementation on Nutritional Status and Physical Performance Under Calorie Restriction. Indian J Clin Biochem 2015; 30:187-93. [PMID: 25883427 DOI: 10.1007/s12291-014-0437-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 04/15/2014] [Indexed: 12/24/2022]
Abstract
L-carnitine is popular as a potential ergogenic aid because of its role in the conversion of fat into energy. The present study was undertaken to investigate the effect of short term supplementation of L-carnitine on metabolic markers and physical efficiency tests under short term calorie restriction. Male albino rats were divided into four groups (n = 12 in each)-control, calorie restricted (CR for 5 days, 25 % of basal food intake), L-carnitine supplemented (CAR, given orally for 5 days at a dose of 100 mg/kg), CR with L-carnitine supplementation (CR + CAR). Food intake and body weight of the rats were measured along with biochemical variables like blood glucose, tissue glycogen, plasma and muscle protein and enzymatic activities of CPT-1 (carnitine palmitoyl transferase-1) and AMP kinase. Results demonstrated that L-carnitine caused marked increase in muscle glycogen, plasma protein, CPT-1 activity and swim time of rats (P < 0.05) on short term supplementation. In addition to the substantive effects caused by CR alone, L-carnitine under CR significantly affected muscle glycogen, plasma protein, CPT-1 activity and AMP kinase (P < 0.05). Short term CR along with L-carnitine also resulted in increased swim time of rats than control, CR and L-carnitine treated rats (P < 0.05). The present study was an attempt towards developing an approach for better adherence to dietary restriction regimen, with the use of L-carnitine.
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Affiliation(s)
- Swati Jain
- Nutrition Division, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054 India
| | - Som Nath Singh
- Nutrition Division, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi, 110054 India
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Effect of L-carnitine Supplementation on Circulating C-reactive Protein Levels: A Systematic Review and Meta-Analysis. J Med Biochem 2015; 34:151-159. [PMID: 28356827 PMCID: PMC4922328 DOI: 10.2478/jomb-2014-0030] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 01/15/2014] [Indexed: 11/20/2022] Open
Abstract
Background C-reactive protein (CRP) has been proposed as a risk marker and risk factor of cardiovascular disease. There have been a number of clinical reports suggesting that supplementation with L-carnitine can modulate systemic inflammation and lower circulating CRP concentrations, but the results have not been consistent. Methods A comprehensive literature search in Medline, Scopus and Cochrane Central Register of Controlled Trials was performed in December 2012 to identify clinical trials investigating the impact of oral L-carnitine supplementation on serum/plasma CRP concentration. A random effect method was used to calculate the combined effect size. Results Six studies comprising 541 cases and 546 controls met the inclusion criteria. Meta-analysis of included trials revealed a significant reduction of circulating CRP concentrations in subjects under L-carnitine intervention compared to the control treatment. The calculated combined weighted mean reduction in CRP concentrations was −0.39 mg/L [95% CI (−0.62 – −0.16)]. This effect size estimate was found to be robust and remained unaffected by the removal of each single study. Conclusions The overall findings of the present meta-analysis support the clinically relevant benefit of L-carnitine supplementation in lowering the circulating levels of CRP.
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Cahova M, Chrastina P, Hansikova H, Drahota Z, Trnovska J, Skop V, Spacilova J, Malinska H, Oliyarnyk O, Papackova Z, Palenickova E, Kazdova L. Carnitine supplementation alleviates lipid metabolism derangements and protects against oxidative stress in non-obese hereditary hypertriglyceridemic rats. Appl Physiol Nutr Metab 2015; 40:280-91. [DOI: 10.1139/apnm-2014-0163] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The aim of this study was to estimate the effect of carnitine supplementation on lipid disorders and peripheral tissue insulin sensitivity in a non-obese animal model of insulin resistance, the hereditary hypertriglyceridemic (HHTg) rat. Male HHTg rats were fed a standard diet, and half of them received daily doses of carnitine (500 mg·kg−1body weight) for 8 weeks. Rats of the original Wistar strain were used for comparison. HHTg rats exhibited increased urinary excretion of free carnitine and reduced carnitine content in the liver and blood. Carnitine supplementation compensated for this shortage and promoted urinary excretion of acetylcarnitine without any signs of (acyl)carnitine accumulation in skeletal muscle. Compared with their untreated littermates, carnitine-treated HHTg rats exhibited lower weight gain, reduced liver steatosis, lower fasting triglyceridemia, and greater reduction of serum free fatty acid content after glucose load. Carnitine treatment was associated with increased mitochondrial biogenesis and oxidative capacity for fatty acids, amelioration of oxidative stress, and restored substrate switching in the liver. In skeletal muscle (diaphragm), carnitine supplementation was associated with significantly higher palmitate oxidation and a more favorable complete to incomplete oxidation products ratio. Carnitine supplementation further enhanced insulin sensitivity ex vivo. No effects on whole-body glucose tolerance were observed. Our data suggest that some metabolic syndrome-related disorders, particularly fatty acid oxidation, steatosis, and oxidative stress in the liver, could be attenuated by carnitine supplementation. The effect of carnitine could be explained, at least partly, by enhanced substrate oxidation and increased fatty acid transport from tissues in the form of short-chain acylcarnitines.
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Affiliation(s)
- Monika Cahova
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague 4, Czech Republic
| | - Petr Chrastina
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague 2, Czech Republic
| | - Hana Hansikova
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague 2, Czech Republic
| | - Zdenek Drahota
- Institute of Physiology, Czech Academy of Sciences, Prague 4, Czech Republic
| | - Jaroslava Trnovska
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague 4, Czech Republic
| | - Vojtech Skop
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague 4, Czech Republic
- Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague 6, Czech Republic
| | - Jana Spacilova
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague 2, Czech Republic
| | - Hana Malinska
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague 4, Czech Republic
| | - Olena Oliyarnyk
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague 4, Czech Republic
| | - Zuzana Papackova
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague 4, Czech Republic
| | - Eliska Palenickova
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague 4, Czech Republic
- Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague 2, Czech Republic
| | - Ludmila Kazdova
- Center for Experimental Medicine, Institute for Clinical and Experimental Medicine, Videnska 1958/9, Prague 4, Czech Republic
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Influence of acute exercise of varying intensity and duration on postprandial oxidative stress. Eur J Appl Physiol 2014; 114:1913-24. [DOI: 10.1007/s00421-014-2912-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 05/12/2014] [Indexed: 12/31/2022]
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Bescós R, Sureda A, Tur JA, Pons A. The effect of nitric-oxide-related supplements on human performance. Sports Med 2012; 42:99-117. [PMID: 22260513 DOI: 10.2165/11596860-000000000-00000] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Nitric oxide (NO) has led a revolution in physiology and pharmacology research during the last two decades. This labile molecule plays an important role in many functions in the body regulating vasodilatation, blood flow, mitochondrial respiration and platelet function. Currently, it is known that NO synthesis occurs via at least two physiological pathways: NO synthase (NOS) dependent and NOS independent. In the former, L-arginine is the main precursor. It is widely recognized that this amino acid is oxidized to NO by the action of the NOS enzymes. Additionally, L-citrulline has been indicated to be a secondary NO donor in the NOS-dependent pathway, since it can be converted to L-arginine. Nitrate and nitrite are the main substrates to produce NO via the NOS-independent pathway. These anions can be reduced in vivo to NO and other bioactive nitrogen oxides. Other molecules, such as the dietary supplement glycine propionyl-L-carnitine (GPLC), have also been suggested to increase levels of NO, although the physiological mechanisms remain to be elucidated. The interest in all these molecules has increased in many fields of research. In relation with exercise physiology, it has been suggested that an increase in NO production may enhance oxygen and nutrient delivery to active muscles, thus improving tolerance to physical exercise and recovery mechanisms. Several studies using NO donors have assessed this hypothesis in a healthy, trained population. However, the conclusions from these studies showed several discrepancies. While some reported that dietary supplementation with NO donors induced benefits in exercise performance, others did not find any positive effect. In this regard, training status of the subjects seems to be an important factor linked to the ergogenic effect of NO supplementation. Studies involving untrained or moderately trained healthy subjects showed that NO donors could improve tolerance to aerobic and anaerobic exercise. However, when highly trained subjects were supplemented, no positive effect on performance was indicated. In addition, all this evidence is mainly based on a young male population. Further research in elderly and female subjects is needed to determine whether NO supplements can induce benefit in exercise capacity when the NO metabolism is impaired by age and/or estrogen status.
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Affiliation(s)
- Raúl Bescós
- National Institute of Physical Education INEFC-Barcelona, Physiology Laboratory, University of Barcelona, Barcelona, Spain.
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Role of carnitine in the regulation of glucose homeostasis and insulin sensitivity: evidence from in vivo and in vitro studies with carnitine supplementation and carnitine deficiency. Eur J Nutr 2011; 51:1-18. [PMID: 22134503 DOI: 10.1007/s00394-011-0284-2] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 11/17/2011] [Indexed: 10/15/2022]
Abstract
BACKGROUND Although carnitine is best known for its role in the import of long-chain fatty acids (acyl groups) into the mitochondrial matrix for subsequent β-oxidation, carnitine is also necessary for the efflux of acyl groups out of the mitochondria. Since intracellular accumulation of acyl-CoA derivatives has been implicated in the development of insulin resistance, carnitine supplementation has gained attention as a tool for the treatment of insulin resistance. More recent studies even point toward a causative role for carnitine insufficiency in developing insulin resistance during states of chronic metabolic stress, such as obesity, which can be reversed by carnitine supplementation. METHODS The present review provides an overview about data from both animal and human studies reporting effects of either carnitine supplementation or carnitine deficiency on parameters of glucose homeostasis and insulin sensitivity in order to establish the less well-recognized role of carnitine in regulating glucose homeostasis. RESULTS Carnitine supplementation studies in both humans and animals demonstrate an improvement of glucose tolerance, in particular during insulin-resistant states. In contrast, less consistent results are available from animal studies investigating the association between carnitine deficiency and glucose intolerance. The majority of studies dealing with this question could either find no association or even reported that carnitine deficiency lowers blood glucose and improves insulin sensitivity. CONCLUSIONS In view of the abovementioned beneficial effect of carnitine supplementation on glucose tolerance during insulin-resistant states, carnitine supplementation might be an effective tool for improvement of glucose utilization in obese type 2 diabetic patients. However, further studies are necessary to explain the conflicting observations from studies dealing with carnitine deficiency.
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Mingorance C, Rodríguez-Rodríguez R, Justo ML, Alvarez de Sotomayor M, Herrera MD. Critical update for the clinical use of L-carnitine analogs in cardiometabolic disorders. Vasc Health Risk Manag 2011; 7:169-76. [PMID: 21490942 PMCID: PMC3072740 DOI: 10.2147/vhrm.s14356] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Indexed: 01/12/2023] Open
Abstract
Acetyl-L-carnitine (ALC) and propionyl-L-carnitine (PLC) are two naturally occurring carnitine derivates formed by carnitine acetyltransferase. The beneficial cardiovascular effects of ALC and PLC have been extensively evaluated in animals and humans during the last 20 years. For instance, many clinical trials have suggested ALC and PLC as potential strategies in the management of peripheral arterial disease, heart and cerebral ischemia, and congestive heart failure. As a result, several experts have already aimed to revise the clinical evidence supporting the therapeutic use of ALC and PLC. On the basis of their conclusions, our aim was a critical review of the effectiveness of ALC and PLC in the treatment of cardiovascular diseases. Type 2 diabetes mellitus is an independent risk factor for the development of cardiovascular disease. Therefore we also describe recent studies that have addressed the emerging use of ALC and PLC amelioration of the insulin resistant state and its related morbidities.
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Affiliation(s)
- Carmen Mingorance
- Department of Pharmacology, School of Pharmacy, University of Seville, Seville, Spain
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