Department of Agriculture’s FoodData Central does not include the carnitine content of foods. ĭata on the carnitine content of specific foods are limited. The bioavailability of acetyl-L-carnitine has not been well studied. ĭietary carnitine has a bioavailability of about 63% to 75%. Poultry, fish, and dairy foods also provide some carnitine, but vegetables, fruits, and grains provide negligible amounts. Sources of CarnitineĬarnitine is present in animal products, especially red meat. Therefore, the FNB did not establish Dietary Reference Intakes (DRIs) for carnitine. In 1989, the Food and Nutrition Board (FNB) of the National Academies of Sciences, Engineering, and Medicine concluded that carnitine is not an essential nutrient. Healthy children and adults do not need to consume carnitine from food or supplements because the liver and kidneys synthesize sufficient amounts to meet daily needs. A ratio of 0.4 or greater in plasma or serum indicates abnormal carnitine metabolism and suggests carnitine insufficiency. The ratio of acyl-L-carnitine ester to free L-carnitine can also be used to assess carnitine status because under normal conditions most carnitine is in the free unesterified form. A plasma free carnitine concentration of 20 mcmol/L or less, or a total carnitine concentration of 30 mcmol/L or less, is abnormally low. Ĭarnitine status is not routinely assessed in clinical practice, but it can be determined by measuring circulating carnitine. A person weighing 165 lb who follows a strict vegetarian diet, for example, synthesizes approximately 14.4 mg/day carnitine. Įndogenous carnitine synthesis does not appear to be affected by dietary carnitine intake or carnitine excretion and is sufficient to meet the carnitine needs of healthy people. In contrast, a vegan diet provides about 1.2 mg carnitine. A typical omnivorous diet provides about 24 to 145 mg carnitine daily for a person weighing 165 pounds. Foods of animal origin provide most of the carnitine in American diets. The body needs about 15 mg/day of carnitine from a combination of dietary sources and endogenous synthesis. Excess plasma carnitine is excreted in urine. Most of the remainder is stored in the liver and kidney, and circulating plasma contains only about 0.5% of the body’s carnitine. About 95% of total body carnitine is stored in heart and skeletal muscle. Ĭarnitine is concentrated in tissues that oxidize fatty acids as a dietary fuel. Carnitine also helps transport some toxic compounds out of the mitochondria. It is an essential cofactor that helps transport long-chain fatty acids into the mitochondria so that they can be oxidized to produce energy in the form of adenosine triphosphate (ATP). Ĭarnitine plays a critical role in energy production. Carnitine is a conditionally essential nutrient because the requirements for carnitine exceed an individual’s ability to synthesize this nutrient only under certain conditions (e.g., premature birth or kidney disfunction). Carnitine is also synthesized endogenously in the liver, kidneys, and brain from the amino acids lysine and methionine. Carnitine is naturally present in many foods-especially foods of animal origin-and is available as a dietary supplement. IntroductionĬarnitine, derived from an amino acid, is the generic term for several compounds, including L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine. For a general overview of Carnitine, see our consumer fact sheet on Carnitine. This is a fact sheet intended for health professionals.
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