Professor Paul Greenhaff, from the School of Biomedical Sciences at the University of Nottingham Medical School, fired off the missive to EFSA’s Panel on Dietetic Products, Nutrition and Allergies (NDA) after assessing the reference list in the negative opinion.
“I am writing to make you aware that you have missed important literature concerning L-Carnitine supplements,” professor Greenhaff began.
“Whilst it is correct to state that L-carnitine supplementation per se will not impact upon a number of facets of health and well being, it is clear from the literature that cardiac tissue is sensitive to carnitine availability.”
“Furthermore, and probably more important in the context of your report, we have published a series of papers over the past decade demonstrating that increasing muscle carnitine content in humans, via insulin mediated stimulation of muscle carnitine transport, has clear effects on tissue carnitine content, muscle metabolism concerned with the regulation of fat and carbohydrate oxidation (at rest and during exercise) and exercise performance.”
After pointing the Panel to a number of ‘missing papers’, the professor concluded:
“I would be grateful if you could amend your document as soon as possible to take into account these research findings because at present its conclusions are incorrect and misleading. The literature sourced is also, in the main, out of date.”
Swiss L-carnitine supplier Lonza would said it had been involved in the 2007 submission of the general function dossier.
Spokesperson Adriana Williams told NutraIngredients: “Yes, in 2007 we submitted different health claims backed by the available scientific research at the time.”
But she said the company did not wish to add further comment on the situation, “at this time.”
Clear metabolic effects
Professor Greenhaff emailed this publication to add:
“It’s important to recognise that from the perspective of muscle where 95% of the body carnitine store is located, ingesting L-carnitine per se will have no impact on tissue stores and therefore some of the points raised are the report are indeed correct.”
“What is frustrating however, from my own perspective, is that the panel have completely missed a whole series of papers from my laboratory showing that if you can actually get carnitine to enter muscle (via insulin mediated stimulation of its transport) it can have a clear metabolic effects.”
The NDA opinion found L-carnitine does not aid faster recovery from muscle fatigue after exercise; does not assist skeletal muscle tissue repair, increase endurance capacity, maintain normal blood LDL-cholesterol concentrations, contribute to normal spermatogenesis, increase L-carnitine concentrations and/or decrease free fatty acids in blood during pregnancy.