title: Effect of L-carnitine supplementation on the body carnitine pool, skeletal muscle energy metabolism and physical performance in male vegetarians.
abstract: OBJECTIVE
  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 (VO2max) and workload (P max) per bodyweight (bicycle spiroergometry) were not significantly different between vegetarians and omnivores. Sub-maximal exercise (75% VO2max 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 max and VO2max 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.
authors.affiliation: Division of Clinical Pharmacology and Toxicology, University Hospital Basel, CH-4031, Basel, Switzerland.|Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: Katerina
authors.initials: K
authors.lastname: Novakova
authors.affiliation: Division of Clinical Pharmacology and Toxicology, University Hospital Basel, CH-4031, Basel, Switzerland.|Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Kummer
authors.affiliation: Division of Clinical Pharmacology and Toxicology, University Hospital Basel, CH-4031, Basel, Switzerland.|Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: Jamal
authors.initials: J
authors.lastname: Bouitbir
authors.affiliation: Division of Clinical Pharmacology and Toxicology, University Hospital Basel, CH-4031, Basel, Switzerland.
authors.forename: Sonja D
authors.initials: SD
authors.lastname: Stoffel
authors.affiliation: Division of Clinical Pharmacology and Toxicology, University Hospital Basel, CH-4031, Basel, Switzerland.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Hoerler-Koerner
authors.affiliation: Division of Clinical Pharmacology and Toxicology, University Hospital Basel, CH-4031, Basel, Switzerland.|Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Bodmer
authors.affiliation: Division of Clinical Pharmacology and Toxicology, University Hospital Basel, CH-4031, Basel, Switzerland.|Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: Paul
authors.initials: P
authors.lastname: Roberts
authors.affiliation: Department of Anesthesia, University Hospital Basel, Basel, Switzerland.
authors.forename: Albert
authors.initials: A
authors.lastname: Urwyler
authors.affiliation: Division of Clinical Pharmacology and Toxicology, University Hospital Basel, CH-4031, Basel, Switzerland.
authors.forename: Rolf
authors.initials: R
authors.lastname: Ehrsam
authors.affiliation: Division of Clinical Pharmacology and Toxicology, University Hospital Basel, CH-4031, Basel, Switzerland. kraehenbuehl@uhbs.ch.|Department of Biomedicine, University of Basel, Basel, Switzerland. kraehenbuehl@uhbs.ch.
authors.forename: Stephan
authors.initials: S
authors.lastname: Krähenbühl
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D002331:Carnitine / Q000008:administration & dosage* / Q000097:blood / Q000652:urine; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D019587:Dietary Supplements; D002149:Energy Intake; D004734:Energy Metabolism / Q000187:drug effects*; D015444:Exercise / Q000502:physiology*; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D000066988:Vegetarians; D055815:Young Adult
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D006003:Glycogen; D002331:Carnitine
keywords: Energy metabolism; L-carnitine supplementation; Skeletal muscle; Spiroergometry; Vegetarians