The effect of l-carnitine on fat oxidation, protein turnover, and body composition in slightly overweight subjects.
Metabolism. 2004 Aug;53(8):1002-6.
We used a combined tracer technique with the stable isotopes (13)C and (15)N to gain further insight into the metabolic changes that accompany supplementation of l-carnitine. The aim of the present study was to investigate whether l-carnitine supplementation can influence fat oxidation, protein turnover, body composition, and weight development in slightly overweight subjects. Twelve volunteers received an individual regular diet either without or with l-carnitine supplementation of 3 grams a day for 10 days. Body fat mass, total body water, and lean body mass were calculated by using bioelectric impedance analysis. L-carnitine supplementation led to a significant increase in protein synthesis indicating that the increased dietary fat oxidation in slightly overweight subjects was not accompanied by protein catabolism.
Caffeine, carnitine and choline supplementation of rats decreases body fat and serum leptin concentration as does exercise.
J Nutr 2000 Feb;130(2):152-7
The effect of a combination of caffeine, carnitine and choline with or without exercise on changes in body weight, fat pad mass, serum leptin concentration and metabolic indices was determined in 20 male, 7-wk-old Sprague-Dawley rats. They were given free access to a nonpurified diet without or with caffeine, carnitine and choline at concentrations of 0.1, 5 and 11.5 g/kg diet, respectively. In a 2x2 factorial design, one-half of each dietary group was exercised, and the other half was sedentary. Food intake of the groups was not different, but the body weight was significantly reduced by exercise in both dietary groups. Fat pad weights and total lipids of epididymal, inguinal and perirenal regions were significantly reduced by the supplements as well as by exercise. Regardless of exercise, supplements significantly lowered triglycerides in serum but increased levels in skeletal muscle. Serum leptin concentrations were equally lowered by supplements and exercise. Serum leptin was correlated with body weight, fat pad weight and serum glucose. We conclude that the indices of body fat loss due to dietary supplements with carnitine were similar to those due to mild exercise, and there were no interactive effects of the two variables.