What Is L-Carnitine For?

Carnitine is a nonessential amino acid made naturally by the body and used to convert fat into energy. It is produced by the liver and kidneys and stored in the muscle, brain, heart and sperm. Carnitine is available in food sources as well, such as lamb, red meat, fish, poultry, dairy and peanut butter. The derivative of natural carnitine is L-carnitine, typically used in treating deficiencies caused by inadequate production or delivery of the substance. The use of L-carnitine has been suggested for many conditions, but the most promising include the treatment of certain diabetic and heart conditions.

Insulin Resistance

In May 2010, the American Diabetes Association issued a press release regarding a study that involved L-carnitine supplementation in combination with a low-calorie diet to improve insulin resistance in type 2 diabetes. Sixteen participants were divided into two groups; both were placed on low-calorie diets with only one group taking 2 g of L-carnitine twice a day. After 10 days, both groups saw positive changes in their responses to glucose, but the L-carnitine group had positive changes in insulin levels.

Cholesterol in Type 2 Diabetes

Another study evaluated the effects of L-carnitine on "bad" cholesterol, or LDL, levels in diabetics. The December 2008 issue of the "American Journal of Clinical Nutrition," reported that 81 diabetic patients were split into two groups over a three-month period and were given either a placebo or 2 g of L-carnitine daily. The patients taking L-carnitine showed an average LDL decrease of 15 points, whereas the placebo group experienced only a 3 point drop.

Diabetic Neuropathy

L-carnitine may also help alleviate pain associated with diabetic neuropathy, a condition involving nerve damage in people with diabetes. A study published in January 2005 in "Diabetes Care," compared two 52-week clinical trials that used acetyl-L-carnitine, another form of L-carnitine, given in two different doses of 500 mg and 1,000 mg three times daily. The results showed an increase in nerve fibers and in "regenerating nerve fibers." Pain reduction was improved at the 1,000 mg level.

Heart Conditions

The University of Maryland Medical Center reports that carnitine can be beneficial in relieving angina, or chest pain, especially during exercise. L-carnitine may strengthen the heart muscle. Little evidence exists to support the use of L-carnitine for reducing subsequent heart attacks. More research is needed for further analysis. The "Cardiovascular Drugs and Therapy" journal published a study in December 2007 involving the use of L-carnitine in conjunction with traditional therapy for coronary heart disease. Researchers randomly assigned 96 participants into two groups, both receiving the coronary intervention therapy, but one receiving L-carnitine in addition. The combined therapy resulted in reductions in the enzymes that mark the increased risk of a heart attack, supporting the need for further research.

Warnings

Avoid carnitine in the form of D-carnitine, or "D, L-carnitine" because they can interfere with natural carnitine function. Additionally, L-carnitine can interact with certain medications; seek medical advice from before supplementing your diet.