Carnitine is a nutrient responsible for the transport of long-chain fatty acids into the energy-producing centers of the cells (known as the mitochondria). It helps the body convert fatty acids into energy, which is used primarily for muscular activities throughout the body. A healthcare provider may recommend use of the supplement levocarnitine (L-Carnitine) for individuals who have a suspected or confirmed deficiency of this nutrient. L-Carnitine is synthesized in the human body, chiefly in the liver and kidneys, from the essential amino acids L-lysine and L-methionine. Niacin, vitamins B6 and C, and iron are involved in its biosynthesis. L-Carnitine is described as a conditionally essential nutrient. Carnitine deficiencies may be caused by genetic disorders, liver or kidney problems, high-fat diets, certain medications, and low dietary levels of the amino acids lysine and methionine (substances needed to make carnitine). Carnitine deficiencies may cause symptoms such as fatigue, chest pain, muscle pain, weakness, low blood pressure, and/or confusion.
Dietary Carnitine can be easily obtained in a number of foods. Perhaps the best source is meat, particularly beef, sheep, and lamb. Other animal foods such as milk, cheese, and poultry contain somewhat less carnitine, while fruits and vegetables have negligible amounts. Supplemental L-Carnitine may have cardioprotective activity in addition to beneficially affecting cardiac function. It may have a triglyceride-lowering effect in some as well as help to elevate HDL-cholesterol levels. L-Carnitine may also have antioxidant properties. The strongest evidence for the use of supplemental L-Carnitine may be in the management of cardiac ischemia and peripheral arterial disease. It may also more generally be indicated for cardioprotection. It lowers triglyceride levels and increases levels of HDL-cholesterol in some. It is used with some benefit in those with primary and secondary Carnitine deficiency syndromes. There is less evidence to support arguments that Carnitine is indicated in liver, kidney and immune disorders or in diabetes and Alzheimer's disease. There is little evidence that supplemental L-Carnitine boosts energy, increases athletic performance or inhibits obesity. There is no support for the claim that healthy vegetarians require L-Carnitine supplementation. Studies suggest that people who take L-Carnitine supplements soon after suffering a heart attack may be less likely to suffer a subsequent heart attack, die of heart disease, experience chest pain and abnormal heart rhythms, or develop congestive heart failure.
References:
PDR Health. http://www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/lca_0060.shtml
University of Maryland Medical Center. http://www.umm.edu/altmed/articles/carnitine-l-000291.htm
