Belongs to the urea cycle group of amino acids along with citrulline and ornithine. L-arginine is not considered essential, but must in some cases be regarded as such, i.e. during phases of rapid growth, pregnancy, protein deficiency and malnutrition, traumas, and excess ammonium and lysine in the tissues.
Accumulated ammonium may occur in cases of gastrointestinal bleedings, kidney failure, and other abnormal conditions. Since many conditions can lead to arginine deficiency, an arginine supplement may have many practical clinical possibilties.
Large amounts of arginine can be found in cheese, eggs, milk and especially in meat - mostly in venison and pork. Arginine is important for the metabolism, where it plays a key role in storing, transporting and discharging nitrogen. The energy-intensive compounds in the muscles - like creatine - are made from arginine.
This amino acids hinder the formation of tumours and the growth of cancer. Experiments with animals, where a diet with a 5% arginine supplement has been used, have shown that the supplement can reduce many of the precursors of cancer in the bloodstream, double the survival time and reduce the number of tumours.
The NK-cells - the natural killer cells - and some of the other cells are the key factors in the immune system's defence against cancer. Therefore, some therapists have begun to give their cancer patients a daily supplement of up to 12 g of arginine.
However, a small number of the mentioned surveys seem to contradict some of the positive results, especially when it comes to certain types of cancer. This is probably why some therapists hesitate when it comes to adding arginine to their cancer treatment programmes.
Further research into this area is badly needed. Look under Cancer in Health Problems.
Arginine - like ornithine and asparagine acid - can be good for male sterility caused by motility problems in the sperm. The seminal fluid contains up to 80 % of this amino acid. (The problem can also be zinc deficiency).
Arginine induces the healing of wounds and the resistance to diseases, enhances the thymic activity and thereby the immune system. It also promotes glucose tolerance and the oxidation of fatty tissue and thereby weight loss. Arginine is vital to a normal function of the hypophysis, it promotes liver regeneration, releases growth hormones, and increases the production of creatine. It also forms the amino acids citrulline and ornithine in the process of hydrolysis - see the chapters on these amino acids.
Arginine and nitrogen oxide (NO)
An arginine supplement possibly can relieve some symptoms of severe cases of malaria. The mode of operation seems to be that arginine increases the body's production of the signalling substance NO (nitrogen oxide) which increases the blood flow and thereby counteracts infected blood cells sticking to the vessel walls. NO acts as a signalling substance several places in the body, both in smooth and cardiac muscle tissue and in the male reproductive organ, where the endothelium (the inner layer of cells in blood vessels) produce NO from arginine and oxygen. This makes the muscle in the vessel wall relax and thus enables the erection.
Generally 2 g a day on an empty stomach, just before going to sleep or - in the opinion of some therapists - 3 g twice a day. Up to 8 g for male sexual problems. To keep the mind clear: no more than 30 mg a day.
Like methionine, taurine and glycine, arginine is good for the cholesterol level. Dosage of 6 mg can reduce cholesterol with up to 10%. This effect is also induced by a healthy diet that contains little lysine and much arginine, probably due to the fact that the meat protein has been replaced by proteins from cereals.
Arginine supplements should by all means be avoided in case of herpes infection - see more on this in the chapter on lysine. Should not be taken isolated or in the large doses by growing children or people who have schizophrenic tendencies.
Dry, rough skin can be a sign of overdose. A dosage of more than 40 g a day can - in patients with liver - or kidney diseases - result in life-threatening conditions with high potassium - and phosphorus levels in the blood. Very large supplements of arginine can result in aqueous diarrhoea.
Patients who suffer from a pseudomonas infection should avoid arginine in their diet and as a supplement since the infection thrives on this amino acid. A low-arginine diet can help control the disease.