Radioisotopic determination of l-carnitine content in foods commonly eaten in Western countries

l-Carnitine is a vitamin-like nutrient essential for energy production and lipid metabolism in many organs and tissues such as skeletal muscle and heart. Even if l-carnitine can be synthesized, most of the carnitine present in human body is provided by food. Until now, no large study has been conducted where the content in l-carnitine of various foods was analyzed. The objective of this study was to determine the level of free l-carnitine present in food commonly consumed in Western countries. A radioisotopic assay was used to estimate l-carnitine content in raw and processed foods. From this study, it clearly appeared that meat products were the best sources for l-carnitine. Dairy products, seafood and fish are generally relatively low in carnitine whereas vegetables are mostly very low in carnitine. An omnivorous regimen allows to meet the general recommendation on l-carnitine intake. Vegetarian are clearly below recommendation and their carnitine homeostasis has to be carried out by a functional biosynthesis.