Carnitine
CARNITINE is not a true amino acid, and is sometimes referred to as Vitamin BT. Because it does have a chemical structure that is similar to an amino acid, it is usually included with that group. In 1947, a scientist, who was studying folic acid and its role in the mealworm, noticed that the mealworm required a certain unnamed factor present in charcoal filtrate of yeast. He named this factor "Vitamin BT" -- B for the family of vitamins and T for the mealworms scientific name Tenebrio molitor. When the mealworms were fed a diet lacking the BT factor, they died in about a month. But when very small amounts of BT was added to the diet, they grew normally. It was then discovered that this factor was also present in yeast, liver, milk, and whey. By 1948, scientists were proving that BT was identical with carnitine, an ammonium compound discovered in 1905.
In humans, carnitine is synthesized in the liver and kidneys and is, therefore, considered a non-essential amino acid. However, there are conditions when it must come from the diet. Carnitine is essential for newborns because of their inadequate ability to synthesize. Adults who have genetic disorders or diseases must rely on supplementation. Others who have difficulty in converting carnitine within their bodies include pre-term babies; non-ketotic types of hypoglycemia; kidney dialysis patients; and those that have cirrhosis of the liver, kwashiorkor, type IV hyperlipidemia, cardiomyopathy or propionic or organic aciduria. In all these conditions, as well as in the inborn errors of metabolism, carnitine is essential to life and must be supplemented.
Carnitine belongs to the same chemical family (quaternary amines) as choline, another nutrient some classify as a B vitamin. Carnitine is used in the body as a coenzyme that acts more like a vitamin than a protein. Because its chemical structure is like that of an amino acid, carnitine plays a dual role. It does not help in protein synthesis, nor is it used as a neurotransmitter. Its main function seems to be transporting long chain fatty acids that will be eventually used for energy. Carnitine is converted from lysine and methionine and is dependent upon adequate amounts of Vitamin C, iron, thiamin (B1), and Vitamin B6 being present for the process.
Since carnitine is an alcohol and contains nitrogen, it is very soluble in water. In order for carnitine to be manufactured in the body, cofactors must be available in sufficient amounts. These cofactors are lysine, methionine, niacin (B3), thiamin (B1), B6, Vitamin C, and iron. Carnitine also enhances the effectiveness of antioxidants Vitamins E and C.
The highest levels of carnitine are found in the heart, skeletal muscles, kidneys, and liver, with the lowest amounts found in the brain and blood serum. Men seem to require more than women since higher levels of carnitine are found in the blood of men and in the epididymis. Carnitine comes in two forms -- L-carnitine, the active form found in body tissues; and the "D" form, which is the inactive mirror image. There is also a mixture of the two known as "DL," but there are side effects with this one. The L form should be the only one used as a supplement of any worth.
Carnitine is vital in fat metabolism and in the reduction of triglycerides. It also helps to transport long-chain fatty acids. Carnitine appears to offer protection against the accumulation of free fatty acids and long chain acyl-CoA-esters which damage the myocardium. Those who have succumbed to heart attacks were found to be deficient in carnatine in the damaged tissue. One to three grams of carnitine taken daily has been found to be helpful in correcting such conditions as intermittent claudication, poor circulation of extremeties, myocardial infarction, and kidney disease; but this must be done under strict supervision.
Dieting often produces a condition known as ketosis, which is a build-up of acid wastes in the blood. This condition can acidify the blood, resulting in calcium, magnesium, and potassium loss, which can be life-threatening. Carnitine supplementation has also improved various dystrophies since the conditions lead to carnitine loss in the urine causing greater requirements.
Those who are greatly deficient tend to be older than 45 and suffer from a number of disorders including heart disease, high blood lipids, kidney disease, cirrhosis of the liver, malnutrition, hypothyroidism, Reye's syndrome, and certain muscular dystrophies. Marginal deficiencies are generally found in those under the age of 45 who fast, participate in strenuous exercise, are obese or pregnant, have frequent sex (males), or who are strict vegetarians. Vegetarians should include protein supplements in their diet or eat foods high in lysine
Heinerman's Encyclopedia lists improvements demonstrated in the following conditions when carnitine was added to the diet:
1) Heart (removed angina or heart pain - Postgraduate Med. Journ. 72:45, 1996).
2) Diabetic heart symptoms (Cardiovas. Research 29:373, 1995).
3) Skeletal muscle tone improvement (Fed. of European Biochem. Soc. Journ. 315:43, Jan. 1993 and Journ. of Clin. Nutr. and Gastro. 8(1):28-29, Jan-Mar 1993).
4) Kidney and liver protection from aging damage of free radicals (Topics in Aging Research in Europe: Liver, Drugs, and Aging 7:104;108-109, 1986 and Biochem. Med. and Metabolic Biol. 43:163-174, 1990).
