The various functions of the essential and frequently investigated non-essential amino acids, their deficiency symptoms and their therapeutic uses are discussed below :

TRYPTOPHAN

Of all the essential amino acids , tryptophan is the one that is most investigated by nutrition researchers. It is essential to blood clotting, digestive juices and the optic system. It induces sleep and quietens the nervous system. It wards off signs of premature old age - cataracts of the eyes, baldness, deterioration of sex glands and malformation of teeth enamel. It is also necessary to the female reproductive organs and for proper utilisation of vitamin A by the body. Major sources of this amino acids are nuts, and most vegetables. Lack of tryptophan causes symptoms similar to those of vitamin A deficiency.

A number of scientists feel that it can be used as a safe and effective food remedy for insomnia and pain. Under experimental conditions, tryptophan in doses of one gram or more has been shown to be most effective for persons who suffer from mild insomnia and for those who take a long time to fall asleep. Tryptophan may also be a natural painkiller. Researches at Temple University in Philadelphia have indicated that it worked without causing the side effects associated with other anesthesia or analgesics.

Tryptophan as a food medicine should be taken between meals with a low protein food such as fruit juice or bread . One to three grams a day seems to be the range favoured by most researchers.

METHIONINE

This is a vital sulphur -bearing compound which helps dissolve cholesterol and assimilates fat. It is required by haemoglobin, the pancreas , the lymph and the spleen. It is necessary to maintain normal body weight and also helps maintain the proper nitrogen balance in the body. Rich sources of methionine are Brazil nut, Hazal nut, and other nuts. It is also found in Brussel sprouts, cabbage, cauliflower, pineapples and apples. Its deficiency can lead to chronic rheumatic fever in children, hardening of the liver (cirrhosis) and nephritis of the kidneys. Studies show that methionine and chorine prevent tumours and proliferation.

LYSINE

Lysine inhibits viruses. Its use along with vitamin C, zinc and vitamin A helps eliminate virus infections. Vitamin C protects this amino acid while in the body so that lysine plus vitamin C has a much stronger anti-virus effect than if either is used seperately. Lysine also influences the female reproductive cycle. Lack of adequate lysine in the diet may cause headaches, dizziness, nausea and incipient anaemia. The main sources of this amino acid are most kinds of nuts, seeds, vegetables and sub-acid fruits. Lysine upsets in the body have also been associated with pneumonia, nephrosis and acidosis as well as malnutrition and rickets in children.
It is considered a natural remedy for cold, sores, shingles and genital herpes. In a study published in 1983, a group of researchers polled over 1,500 people whose daily intake of lysine was over 900 mg. 88 per cent said that lysine seemed to reduce the severity of their attacks of herpes virus and accelerated the healing time. These results have, however, been disputes by some scientists.

VALINE

Valine is an essential body growth factor, particularly for mammary glands and ovaries. Valine is directly linked with the nervous system. It is essential for the prevention of nervous and digestive disorders. Major sources are almonds, apples and most vegetables. Lack of this amino acid makes a person sensitive to touch and sound.

ISOLEUCINE

This amino acid is essential for maintaining the nitrogen balance vital to all body functions. It also regulates metabolism of the thymus, spleen and pituitary glands. Rich sources are sunflower seeds, all nuts, except cashew nuts, avacados and olives.

LEUCINE

It is the compliment of isoleucine, with a similar chemical composition although in different arrangement. Its functions and sources are also similar.