20 different amino acids are used to build up proteins, some of which are essential and must be provided in the diet. Others are non-essential and can be made in the body by a complex process of metabolism from other amino acids we get from diet.

In general, proteins (hence amino acids) are derived from animal sources such as eggs, meat, milk, fish and poultry and are considered complete proteins as these food sources provide all 20 amino acids. Proteins from vegetable sources do not provide all of the amino acids and must therefore be used in combination with one another to receive the full complement.

The main function of Amino Acids is therefore as a building block of successful protein formation. Below is a list of the main aminos and their function in human health.

Arginine
Arginine is incorporated into body proteins and is involved in the urea cycle which detoxifies ammonia in the body. Arginine also stimulates the production of growth hormone and is a precursor of 2 substances found in sperm. It may also be a componant in the formation of Nitric Oxide (NO) which is involved in erectile tissue function in males (NO is the main active ingredient in Viagra)

Ornithine
Ornithine is not incorporated into proteins. However, it functions in a similar way to arginine in the body, but is twice as effective at stimulating growth hormone.

Cysteine
This sulphur-containing amino acid functions as an antioxidant and may help the body to detoxify poisons. Cysteine helps to clear mucus and is required for the growth of healthy hair.

Glutamine
Glutamine is able to cross into the brain from general circulation where it is used as an important energy source. This amino acid may be helpful in the management of peptic ulcers. It has also been shown to be helpful in the management of some craving disorders such as food and alcohol.

Phenylalanine
L-phenylalanine - required for the formation of a number of neurotransmitters and stimulates the release of a hormone used to control appetite. May be beneficial for those with mild depression. Its close 'sister', D-phenylalanine – involved in slowing the breakdown of pain killing substances which are naturally produced in the body, thereby helping to prolong pain relief.

Lysine
An important structural component of many proteins. Lysine is converted into another amino acid needed for fat transport and utilisation. It is also involved in the retention of calcium in the body and maintenance of the immune system. Lysine may be beneficial in the management of herpes simplex (coldsores and to a certain degree genital herpes also)

Vegetarians and vegans are sometimes low in lysine.

Tyrosine
Tyrosine is a component of body proteins and has a similar function to phenylalanine. Tyrosine is used to make a number of brain chemicals and may be beneficial for those with mild-depression and poor concentration.