L-Carnitine

Carnitine is not an amino acid in the strict sense and is actually related to the B vitamins but because it has a chemical structure similar to that of amino acids, it is usually considered together with them. L-carnitine is known chemically as (R)-3-carboxy-2-hydroxy-N,N.N-trimethyl-l-propanaminium hydroxide, gamma-trimethyl-beta-hydroxybutyrobetaine, and 3-hydroxy-4-(trimethylammonio) butanoate. L-carnitine is also known as levocarnitine and earlier was called vitamin BT. L-carnitine is a quarternary amine and belongs to the same chemical family as choline and is soluble in water. L-carnitine is a chiral molecule and its stereoisomer D-carnitine does not have the biological activity of L-carnitine and may even inhibit L-carnitine in its biological roles.

Function- L-carnitine is found in nearly all cells of the body. Most of the body's stores of L-carnitine are found in cardiac and skeletal muscle. Carnitine is not used for protein synthesis or as a neurotransmitter like true amino acids. Its main function is to help transport long-chain fatty acids to the mitochondria, to provide energy in the form of ATP (adenosine triphosphate). Utilizing fat in this way is a major source of energy for the muscles, and the heart is a muscle. This process is useful in preventing fatty buildup, especially in the heart, liver, and skeletal muscles.

Favorable results have been reported for many years with regard to the use of L-carnitine in the treatment of various forms of cardiovascular disease as well as reducing the health risks posed by poor fat metabolism associated with diabetes and inhibiting alcohol-induced fatty liver. It may also more generally be indicated for protection of the heart and cardiovascular system. It lowers triglyceride levels and increases levels of HDL-cholesterol in some.

Carnitine may be useful in treating chronic fatigue syndrome (CFS). In chronic fatigue syndrome there is a disturbance in the function of the mitochondria (the site of energy production within the cells) and L-carnitine affects this area. Studies have shown decreased carnitine levels in people with CFS.

Carnitine also enhances the effectiveness of the antioxidant vitamins E and C. It works with antioxidants to help slow the aging process by promoting the synthesis of carnitine acetyl-transferease, an enzyme in the mitochondria of brain cells that is vital for the production of cellular energy there. This effect on the brain therefore may relate in the prevention of Alzheimer’s disease. L-carnitine provides numerous other benefits to many of the body's systems. It helps to limit damage caused by oxygen starvation, enhance the immune system, protect against oxidative stress, stimulate the antioxidant activity of certain enzymes, protect membranes, slow cerebral aging, prevent nerve disease associated with diabetes and sciatica, modulate hormonal changes caused by physical stress, and increase the muscle building properties of branched-chain amino acids (isoleucine, leucine, and valine).

Deficiency- Two types of L-carnitine deficiency states exist; primary systemic carnitine deficiency (SCD) and secondary carnitine deficiency syndromes.

Primary systemic carnitine deficiency (SCD )is an autosomal recessive disorder characterized by progressive cardiomyopathy, skeletal myopathy, hypoglycemia and hyperammonemia, SCD appears to be due, in part, to loss of function of a transport protein (called OCT N2) which helps carry L-carnitine into cells. Patients with primary systemic carnitine deficiency (SCD) have low L-carnitine levels in liver and skeletal muscle and variable concentrations of L-carnitine in the serum. Treatment with large doses of L-carnitine either orally or intravenously is sometimes beneficial in this very rare genetic disorder.

Secondary L-carnitine deficiency disorders include a large number of entities. Some of these are genetic defects of metabolism such as cytochrome C oxidase deficiency, methylmalonic aciduria, fatty acyl-coenzyme A dehydrogenase deficiency, glutaric aciduria, isovaleric acidemia, and propionic acidemia. Secondary L-carnitine deficiency may also be found secondary to other conditions such as chronic renal failure treated by hemodialysis, chronic myopathy, cirrhosis with cachexia, myxedema, hypopituitarism, adrenal insufficiency, advanced AIDS and pregnancy.

Possible symptoms of deficiency are heart pain, poor fat metabolism (obesity), confusion, and overall muscle weakness.

Sources- L-carnitine occurs naturally in animal products. Generally, only very small amounts of it are found in plants, with few exceptions, such as avocado and some fermented soy products. L-carnitine is synthesized in the human body, chiefly in the liver and kidneys, from the essential amino acids L-lysine and L-methionine. Carnitine can be manufactured by the body if sufficient amounts of iron, vitamin B1 (thiamine), vitamin B6 (pyridoxine), and vitamin C. Inadequate intake of any of these nutrients can result in a carnitine deficiency.

Precautions- Mild gastrointestinal symptoms have been reported in those taking oral L-carnitine, including mild nausea, abdominal cramps and diarrhea.

Vegetarians are more likely than non-vegetarians to be deficient in carnitine because it is not found in vegetable protein. Moreover, neither lysine nor methionine, two of the amino acids from which the body makes carnitine, are obtainable from vegetable sources in sufficient amounts. To ensure adequate production of carnitine, vegetarians may need to take supplemental L-carnitine.

Requirements- There is no Recommended Dietary Allowances (RDA) listed. Individual needs may differ due to clinical conditions, biochemical individuality and absorption. All sources of nutrients should be consumed in their most natural state, in the form of a variety of foods or supplements when necessary. Free form amino acid supplements are immediately absorbed by the body and should be consumed with natural occurring cofactors for best results. Consulting with a physician that is properly trained in the natural healing sciences and amino acid therapy may be needed for optimum results. Men do need higher levels of L-carnitine than women mostly due to the increase in muscle mass.

Written by Jerome Rerucha D.C.

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