Por mi parte la L-Carnitina pasa a ser un suplemento más que irá a parar al gran baúl de los suplementos que no valen para nada pero que la industria de la suplementación totalmente carente de ética y moral nos sigue vendiendo con falsas promesas sin ninguna base cientifica solida que respalde sus supuestos beneficios.
1)Un estudio llamado "Effect of L-carnitine on weight loss and body compositi on of rats fed a hypocaloric diet", llevado a cabo por el Institute of Nutrition al Sciences, Universit y of Halle, Germany, administró L-Carnitina a ratas con unos 2.5 gr durante una dieta hipocalórica. La conclusión: la carnitina no mejoró ningún parámetro y la carnitina endógena era suficiente para asegurar la beta oxidación durante una fase catabólica.
Effect of L-carnitine on weight loss and body... [Ann Nutr Metab. 2002] - PubMed - NCBI
Cita:
| Effect of L-carnitine on weight loss and body composition of rats fed a hypocaloric diet. Brandsch C, Eder K. Source Institute of Nutritional Sciences, University of Halle, Germany. Abstract BACKGROUND/AIMS: Several studies have been published in recent years which suggest that L-carnitine supplementation can influence the lipid metabolism in some species and can also affect body composition of growing animals. Only few results are available so far on the effect of L-carnitine supplementation on weight reduction and body composition of animals fed an energy-deficient diet. The aim of this study was therefore to investigate whether L-carnitine supplementation combined with an energy-deficient diet can influence weight development and body composition. METHODS: An experiment was conducted with 36 rats with an initial body weight of about 460 g. One-third of the rats were killed, the remainder were divided into two groups (control group, treated group) and fed a semi synthetic diet at an energy level of about half of the rats' maintenance requirement. The basal diet was essentially carnitine-free. The diet of the treated group was supplemented with L-carnitine (5 g/kg). The feeding period extended over 23 days. Experimental parameters were weight loss, composition of carcass and weights of the fat pads surrounding the kidneys, intestine and testes; several clinico-chemical plasma parameters were also determined. RESULTS: As was to be expected, the rats lost a considerable amount of weight on the energy-reduced diet. At the same time a shift occurred in the ratio of fat to protein in favour of protein in the carcass, leading to a marked reduction of body fat levels and a slight reduction of protein levels. There were, however, no significant differences between the control group and the treated group (with L-carnitine supplementation) with regard to any of these parameters. The clinico-chemical parameters measured in plasma (glucose, triglycerides, total cholesterol, free fatty acids, 3-hydroxybutyric acid) also showed no differences between the groups. CONCLUSIONS: The rat model used here did not show a positive effect of L-carnitine supplementation on weight loss and body composition of rats fed an energy-deficient diet. The animals' endogenous carnitine synthesis was obviously adequate to ensure efficient beta-oxidation of fatty acids during the catabolic phase. Copyright 2002 S. Karger AG, Basel PMID: 12378044 [PubMed - indexed for MEDLINE] |
L-carnitine supplementation does not pr... [Int J Vitam Nutr Res. 2005] - PubMed - NCBI
Cita:
| L-carnitine supplementation does not promote weight loss in ovariectomized rats despite endurance exercise. Melton SA, Keenan MJ, Stanciu CE, Hegsted M, Zablah-Pimentel EM, O'Neil CE, Gaynor P, Schaffhauser A, Owen K, Prisby RD, LaMotte LL, Fernandez JM. Source Department of Kinesiology, School of Health Sciences, West Chester University, West Chester, PA 19383, USA. smelton@wcupa.edu Abstract In this five-week study, we tested the hypotheses that free access to a maintenance diet supplemented with L-carnitine (L-C) would reduce body fat in adult, sedentary, ovariectomized (OVX) rats, and that there would be an additive effect of L-C on weight reduction in swim-trained animals. As expected, serum carnitine was higher in rats fed the L-C diet, and the OVX-induced weight gain and abdominal fat were counteracted by swimming. L-C supplementation did not reduce the weight gain or abdominal fat in these adult female rats, Moreover, though not reaching statistical significance, rats that were fed L-C demonstrated a tendency for greater weight gain than their basal-fed counterparts despite no difference in energy intake. If the results of this study on ovariectomized rats can be translated to postmenopausal women, moderate intensity exercise may be recommended, but L-C supplementation, with no energy restriction, may be contraindicated as a weight loss method in this cohort. PMID: 15929637 [PubMed - indexed for MEDLINE] |
4) Otro estudio llamado "L-Carnitine supplementation combined with aerobic training does not promote weight loss in moderatel y obese women" fue llevado a cabo por el Department of Human Biology and Movement Science, Royal Melbourne Institute of Technolog y, Australia . Administró carnitina a 36 mujeres durante 8 semanas. 5 experimentaron náusea y/o diarrea, y además, la L-Carnitina se mostró totalment e ineficaz para perder peso.
L-Carnitine supplementation com... [Int J Sport Nutr Exerc Metab. 2000] - PubMed - NCBI
Cita:
| L-Carnitine supplementation combined with aerobic training does not promote weight loss in moderately obese women. Villani RG, Gannon J, Self M, Rich PA. Source Department of Human Biology and Movement Science, Royal Melbourne Institute of Technology, Melbourne, Victoria, 3083, Australia. Abstract L-Carnitine (L-C) transports fatty acids into mitochondria for oxidation and is marketed as a weight loss supplement. In a double-blind investigation to test the weight loss efficacy of L-C, 36 moderately overweight premenopausal women were pair matched on Body Mass Index (BMI) and randomly assigned to two groups (N = 18). For 8 weeks the L-C group ingested 2 g twice daily of L-C, while the placebo (P) group ingested the same amount of lactose. All subjects walked for 30 min (60-70% maximum heart rate) 4 days/week. Body composition, resting energy expenditure (REE) and substrate utilization were estimated before and after treatment. For the subjects who completed the study (15 P, 13 L-C), no significant changes in mean total body mass (TBM), fat mass FM, and resting lipid utilization occurred over time, nor were there any significant differences between groups for any variable. Conversely REE increased significantly for all subjects, but no between group differences existed. Five of the L-C group experienced nausea or diarrhea and consequently did not complete the study. Eight weeks of L-C ingestion and walking did not significantly alter the TBM or FM of overweight women, thereby casting doubt on the efficacy of L-C supplementation for weight loss. PMID: 10861338 [PubMed - indexed for MEDLINE] |
Weight loss associated with reduced intake of car... [Metabolism. 2005] - PubMed - NCBI
Cita:
| Weight loss associated with reduced intake of carbohydrate reduces the atherogenicity of LDL in premenopausal women. Lofgren I, Zern T, Herron K, West K, Sharman MJ, Volek JS, Shachter NS, Koo SI, Fernandez ML. Source Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA. Abstract The effect of a 3-tier intervention including dietary modifications (ie, moderate energy restriction, decreased carbohydrate, increased protein), increased physical activity, and the use of carnitine as a dietary supplement was evaluated on plasma lipids and the atherogenicity of low-density lipoprotein (LDL) particles in a population of overweight and obese premenopausal (aged 20-45 years) women. Carnitine or a placebo (cellulose) was randomly assigned to the participants using a double-blind design. Carnitine supplementation was postulated to enhance fat oxidation resulting in lower concentrations of plasma triglycerides. Seventy women completed the 10-week protocol, which followed a reduction in their energy intake by 15% and a macronutrient energy distribution of 30% protein, 30% fat, and 40% carbohydrate. In addition, subjects increased the number of steps taken per day by 4500. As no differences were observed between the carnitine and placebo groups in all the measured parameters, all subjects were pooled together for statistical analysis. Participants decreased (P<.01) their caloric intake (between 4132.8 and 7770 kJ) and followed prescribed dietary modifications as assessed by dietary records. The average number of steps increased from 8950+/-3432 to 12764+/-4642 (P<.001). Body weight, plasma total cholesterol, LDL cholesterol, and triglyceride were decreased by 4.5%, 8.0%, 12.3%, and 19.2% (P<.0001), respectively, after the intervention. Likewise, apolipoproteins B and E decreased by 4.5% and 15% (P<.05) after 10 weeks. The LDL mean particle size was increased from 26.74 to 26.86 nm (P<.01), and the percent of the smaller LDL subfraction (P<.05) was decreased by 26.5% (P<.05) after 10 weeks. In addition, LDL lag time increased by 9.3% (P<.01), and LDL conjugated diene formation decreased by 23% (P<.01), indicating that the susceptibility of LDL to oxidation was decreased after the intervention. This study suggests that moderate weight loss (<5% of body weight) associated with reduced caloric intake, lower dietary carbohydrate, and increased physical activity impacts the atherogenicity of LDL. PMID: 16125523 [PubMed - indexed for MEDLINE] |
The effect of L-carnitine on plasma lipoprotein(a)... [Clin Ther. 2003] - PubMed - NCBI
Cita:
| The effect of L-carnitine on plasma lipoprotein(a) levels in hypercholesterolemic patients with type 2 diabetes mellitus. Derosa G, Cicero AF, Gaddi A, Mugellini A, Ciccarelli L, Fogari R. Source Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy. giuderosa@tin.it Abstract BACKGROUND: A previous study has demonstrated that L-carnitine reduces plasma lipoprotein(a) (Lp[a]) levels in patients with hypercholesterolemia. OBJECTIVE: To test a tolerable Lp(a)-reducing agent in diabetic patients, we assessed the effect of a dietary supplementation of L-carnitine on plasma lipid levels, particularly Lp(a), of patients with type 2 diabetes mellitus (DM) and hypercholesterolemia. METHODS: In this 6-month, randomized, double-masked, placebo-controlled clinical trial, patients were enrolled, assessed, and followed up at the Diabetic and Metabolic Diseases Center of the Department of Internal Medicine and Therapeutics at the University of Pavia, Pavia, Italy. All study patients had newly diagnosed type 2 DM that was managed through dietary restriction alone throughout the study, as well as hypercholesterolemia. Patients were randomized to 1 of 2 groups. One group received L-carnitine, one 1-g tablet BID. The other group received a corresponding placebo. We assessed body mass index, fasting plasma glucose, postprandial plasma glucose, glycosylated hemoglobin, fasting plasma insulin, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoprotein (apo) A-I, apo B, and Lp(a) at baseline and at 1, 3, and 6 months of treatment. RESULTS: This study included 94 patients. The treatment group included 24 men and 22 women (mean [SD] age, 52 [6] years). The placebo group included 23 men and 25 women (mean [SD] age, 50 [7] years). The baseline characteristics of the groups did not differ significantly. The mean (SD) body weight, height, and body mass index were 78.2 (5.8) kg, 1.70 (0.04) m, and 27.3 (2.5) kg/m(2), respectively, in the L-carnitine group and 77.6 (6.4) kg, 1.71 (0.05) m, and 26.8 (2.2) kg/m(2), respectively, in the placebo group. In the treatment group, Lp(a) was significantly reduced at 3 and 6 months compared with baseline (P < 0.05) and P < 0.01, respectively). We observed a significant improvement after 6 months (P < 0.05) in the Lp(a) value in patients taking L-carnitine compared with those taking placebo. Between-group differences in other variables did not reach a level of significance at months 3 and 6. No drug-related adverse events were reported or observed. CONCLUSION: In this preliminary study, after 3 and 6 months, L-carnitine significantly lowered the plasma Lp(a) level compared with placebo in selected hypercholesterolemic patients with newly diagnosed type 2 DM. PMID: 12867219 [PubMed - indexed for MEDLINE] |
Carnitine does not improve weight loss outcom... [Bipolar Disord. 2006] - PubMed - NCBI
Cita:
| Carnitine does not improve weight loss outcomes in valproate-treated bipolar patients consuming an energy-restricted, low-fat diet. Elmslie JL, Porter RJ, Joyce PR, Hunt PJ, Mann JI. Source Department of Psychological Medicine, Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand. jane.elmslie@chmeds.ac.nz Abstract OBJECTIVES: Carnitine deficiency impairs fatty acid beta-oxidation and may partly explain weight gain in valproate-treated patients. The aim of this study was to determine whether l-carnitine supplementation improves weight loss outcomes in bipolar patients taking sodium valproate. METHODS: Sixty bipolar patients with clinically significant weight gain thought to be related to sodium valproate, who had been taking sodium valproate for >or=6 months, were randomized to l-carnitine (15 mg/kg/day) or placebo for 26 weeks, in conjunction with a moderately energy-restricted, low-fat diet. The primary outcome measure was weight change. RESULTS: l-carnitine had no effect on mean weight loss compared with placebo (-1.9 kg versus - 0.9 kg) (F = 0.778, df = 1,58, p = 0.381). The number of people in each group able to lose any weight was identical ( = 0, p = 1.0); more patients in the carnitine group (nine versus five) achieved a clinically significant weight loss (>or=5%) but this was not statistically significant (p = 1.0, Fisher's exact test). CONCLUSIONS: At the dose prescribed in this study carnitine supplementation did not improve weight loss outcomes in valproate-treated bipolar patients consuming an energy-restricted, low-fat diet. PMID: 17042889 [PubMed - indexed for MEDLINE] |
Se puede encontrar un estudio que si encontró reducción de peso. El problema es que el estudio recibió una valoració n de 1 sobre 5 (peor valoració n posible) en la escala de Jadad, que mide la calidad de los ensayos clínicos. Es decir: ni randomiza do, ni doble ciego, ni explica el seguimien to… Un estudio con menos de 3 no se suele aceptar para posterior es inclusion es científic as. Asi que una auténtica chapuza. Pero para que no se diga, aquí lo dejo: "Carnitine, Choline Supplemen tation with Exercise Alter Carnitine Profiles, Biochemic al Markers of Fat Metabolis m and Serum Leptin Concentra tion in Healthy Women"
Carnitine and Choline Supplementation with Exercise Alter Carnitine Profiles, Biochemical Markers of Fat Metabolism and Serum Leptin Concentration in Healthy Women
Despues de esto yo ya lo tengo claro...
a partir de ahí cada cual decide en que gasta su dinero
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