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- Title
Effect of l-carnitine supplementation on the body carnitine pool, skeletal muscle energy metabolism and physical performance in male vegetarians.
- Authors
Novakova, Katerina; Kummer, Oliver; Bouitbir, Jamal; Stoffel, Sonja; Hoerler-Koerner, Ulrike; Bodmer, Michael; Roberts, Paul; Urwyler, Albert; Ehrsam, Rolf; Krähenbühl, Stephan
- Abstract
Purpose: More than 95 % of the body carnitine is located in skeletal muscle, where it is essential for energy metabolism. Vegetarians ingest less carnitine and carnitine precursors and have lower plasma carnitine concentrations than omnivores. Principle aims of the current study were to assess the plasma and skeletal muscle carnitine content and physical performance of male vegetarians and matched omnivores under basal conditions and after l-carnitine supplementation. Results: Sixteen vegetarians and eight omnivores participated in this interventional study with oral supplementation of 2 g l-carnitine for 12 weeks. Before carnitine supplementation, vegetarians had a 10 % lower plasma carnitine concentration, but maintained skeletal muscle carnitine stores compared to omnivores. Skeletal muscle phosphocreatine, ATP, glycogen and lactate contents were also not different from omnivores. Maximal oxygen uptake (VOmax) and workload ( P) per bodyweight (bicycle spiroergometry) were not significantly different between vegetarians and omnivores. Sub-maximal exercise (75 % VOmax for 1 h) revealed no significant differences between vegetarians and omnivores (respiratory exchange ratio, blood lactate and muscle metabolites). Supplementation with l-carnitine significantly increased the total plasma carnitine concentration (24 % in omnivores, 31 % in vegetarians) and the muscle carnitine content in vegetarians (13 %). Despite this increase, P and VOmax as well as muscle phosphocreatine, lactate and glycogen were not significantly affected by carnitine administration. Conclusions: Vegetarians have lower plasma carnitine concentrations, but maintained muscle carnitine stores compared to omnivores. Oral l-carnitine supplementation normalizes the plasma carnitine stores and slightly increases the skeletal muscle carnitine content in vegetarians, but without affecting muscle function and energy metabolism.
- Subjects
SWITZERLAND; SKELETAL muscle physiology; ADENOSINE triphosphate analysis; ANALYSIS of variance; CARDIOPULMONARY system; CARNITINE; CLINICAL trials; CONFIDENCE intervals; DIETARY supplements; EXERCISE tests; GLYCOGEN; LACTIC acid; LONGITUDINAL method; MEN'S health; NEEDLE biopsy; NUTRITIONAL assessment; PHOSPHOCREATINE; PROBABILITY theory; PULMONARY gas exchange; RESEARCH funding; STATISTICAL hypothesis testing; STATISTICS; T-test (Statistics); VEGETARIANISM; STATISTICAL power analysis; DATA analysis; QUADRICEPS muscle; BODY movement; BODY mass index; PRE-tests &; post-tests; REPEATED measures design; OXYGEN consumption; ERGOMETRY; FOOD diaries; DATA analysis software; DESCRIPTIVE statistics
- Publication
European Journal of Nutrition, 2016, Vol 55, Issue 1, p207
- ISSN
1436-6207
- Publication type
Article
- DOI
10.1007/s00394-015-0838-9