Carnitine is a dipeptide – an amino acid made from two other aminos, methionine and lysine. It can be synthesized in the liver if sufficient amounts of lysine, B1, B6 and iron are available. Muscle and organ meat, fish and milk products are the best sources of carnitine in the diet. Vegetarians are more likely to be deficient in carnitine because they don’t eat meat and their diets are often low in lysine.
Carnitine has been shown to have a major role in the metabolism of fat and in the reduction of triglycerides by increasing fat utilization. It transfers fatty acids across the membranes of the mitochondria where they can be utilized as sources of energy. It also increases the rate at which the liver uses fats. By preventing fatty build-up, this amino acid aids in weight loss and decreases the risk of heart disease.
Carnitine has been shown to be deficient in hearts of patients who have died of acute myocardial infections. Supplements have recently been found to improve exercise tolerance in people with angina, possibly by increasing the ability to utilize fatty acids for energy.
Carnitine was also found to block atrial fibrillation after initial atropine administration about as well as quinidine, without many of quinidine’s side effects. It may be deficient, and supplementation may help in mitral valve prolapse and immune system depression. Muscular dystrophy, and myotonic dystrophy have been shown to lead to carnitine loss in the urine, and therefore higher requirements for it.
Carnitine is stored primarily in the skeletal muscles and heart, where it is needed to transform fatty acids into energy for muscular activity. It is also concentrated in sperm and the brain. Many athletes have noted increased endurance and muscle building with carnitine supplementation. The Physicians Desk Reference has recommended l-carnitine in the treatment of ischemic heart disease and Type IV hyperlipidema. Carnitine has been shown to be beneficial for heart problems such as angina, ischemia or arrhythmia, and poor endurance, muscle weakness or obesity.
Deficiencies may increase symptoms of fatigue, angina, muscle weakness or confusion. A low level of Vitamin c will also result in apparent Carnitine deficiency. It is contraindicated for people with liver or kidney disease or diabetes It has proven helpful in improving lipid metabolism and reducing elevated total lipids, cholesterol and triglycerides in people with cardiac problems and diabetes, but should only be taken with medical supervision in these conditions.