Vitamins, Minerals and Dietary Supplements

What is carnitine? Why do we need it?

Carnitine is a non-essential amino acid that the body can manufacture. A dipeptide, carnitine is synthesized in the liver, brain and kidneys from two other amino acids, methionine and lysine.

Carnitine helps transport fatty acids across the cell membrane, thereby increasing the oxidation of fatty acids. It also helps reduce blood triglyceride levels by increasing fat utilization and increasing the rate at which the liver uses fat. In addition, it lowers LDL cholesterol levels, increases HDL cholesterol levels, and increases the body's tolerance to stress.

Laboratory studies have found that carnitine helps reduce the severity of angina attacks and other cardiovascular problems. Some practitioners recommend carnitine to help with high blood cholesterol, high blood pressure and ischemic heart disease.

How much carnitine should I take?

For high cholesterol, some practitioners recommend between 3-4 grams of carnitine per day. Other practitioners recommend carnitine in conjunction with vitamin C to reduce angina.

What are some good sources of carnitine? What forms are available?

Carnitine is manufactured naturally in the body through the synthesis of lysine, methionine, iron, and vitamins B6 and C. Dietary sources of carnitine include beans, beef, chicken, dairy products, seafood, tempeh, wheat germ and whey.

What can happen if I don't get enough carnitine? What can happen if I take too much? Are there any side-effects I should be aware of?

Carnitine deficiency may be caused by low levels of vitamin C in the body or a genetic defect in the cell membranes. Deficiency may lead to a variety of conditions, including hypoglycemia, cardiomyopathy and muscle weakness. Vegetarians may also suffer from low levels of carnitine. Large doses of carnitine, on the other hand, may cause diarrhea, nausea and vomiting.

Patients with kidney problems should not take carnitine supplements. It may also interact negatively with anticonvulsant drugs and some antibiotics, including pivampicillin and pivmecillinam. Make sure to consult with a qualified health practitioner before taking carnitine supplements.

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References

• Angelini C, et al. Clinical study of efficacy of L-carnitine and metabolic observations in exercise physiology. In: Borum (ed.) Clinical Aspects of Human Carnitine Deficiency. New York: Pergamon Press, 1986.
• Cherchi A, et al. Effects of L-carnitine in exercise tolerance in chronic stable angina: a multicenter, double-blind, randomized placebo controlled crossover study. Int J Clin Pharmacology, Therapy and Toxicology 1985;23:569-572.
• Marconi C, et al. Effects of L-carnitine loading on the aerobic and anaerobic performance of endurance athletes. European J Appl Physiol 1985;54:131-135.
• Mason P. Handbook of Dietary Supplements: Vitamins and Other Health Supplements. Cambridge, MA: Blackwell Science, Inc., 1995.
• Pola P, et al. Statistical evaluation of long-term L-carnitine therapy in hyperlipoproteinemias. Drugs Under Experimental and Clinical Research 1983;12:925-935.