Carnitine is a substance used by the body uses to turn fat into energy. It is not normally considered an essential nutrient because the body can manufacture all it needs. However, supplemental carnitine could in theory improve the ability of certain tissues to produce energy. This has led to the use of carnitine for various muscle diseases as well as heart conditions.

Requirements

There is no dietary requirement for carnitine. However, a few individuals have a genetic defect that hinders the body's ability to make carnitine. In addition, diseases of the liver, kidneys, or brain may inhibit carnitine production. Certain medications, especially the antiseizure drugs valproic acid (Depakene) and phenytoin(Dilantin), may reduce carnitine levels; however, whether taking extra carnitine would be helpful has not been determined.1-11 Heart muscle tissue, because of its high energy requirements, is particularly vulnerable to carnitine deficiency.

Food Sources

The National Institutes of Health's Office of Dietary Supplements offers this list of foods that are high in carnitine:114

Food Serving size Carnitine content
(milligrams [mg])
Beef steak, cooked 4 ounces 56-162
Ground beef, cooked 4 ounces 87-99
Milk, whole 1 cup 8
Codfish, cooked 4 ounces 4-7
Chicken breast, cooked 4 ounces 3-5
Ice cream ½ cup 3
Cheddar cheese 2 ounces 2
Whole wheat bread 2 slices 0.2
Asparagus ½ cup 0.1

While carnitine can be found in foods like meat and dairy products, a supplement is necessary to obtain therapeutic dosages.