Amino Acids
What is it?
Amino acids are divided into three main types: essential, nonessential and semi-essential. The essential amino acids are tryptophan, lysine, methionine, phenylalanine, threonine, valine, leucine and isoleucine. Arginine and histidine are considered semi-essential. The non-essential amino acids are tyrosine, glycine, serine, glutamic acid, aspartic acid, taurine, cystine, proline, and alanine.
Meat, fish, eggs, milk and soybeans contain all the essential amino acids and are known as complete proteins. Those foods which are low in some amino acids are called incomplete proteins. For example, legumes are low in methionine and tryptophan, but high in lysine and isoleucine whereas, grains are low in lysine and isoleucine and high in tryptophan and methionine. Two incomplete protein foods, eaten together, can provide a complete protein, for example, baked beans on toast or lentils and rice.
Supplements
Taking one amino acid for a long period of time is not advisable as this may affect the balance and functions of the others. Some experts recommend that single supplements should be taken for no more than two to three weeks.
Essential amino acids
Branched chain amino acids
The branched-chain amino acids, isoleucine, leucine, and valine have been used as supplements for muscle building. Arginine is also used for this purpose. Leucine has also been used to help heal wounds of the skin and bones.
Lysine
Lysine is used to prevent and treat Herpes simplex virus infections. It seems to be more effective for cold sores (herpes type 1) than for genital herpes (type 2). A typical dosage regime is 500 mg three times per day during an infection and 500 mg per day when there are no symptoms.
Phenylalanine
Phenylalanine is used to treat depression, musculoskeletal disorders and various types of pain including back pain, neck pain, osteoarthritis, rheumatoid arthritis, menstrual pain and headaches.
Tryptophan
Tryptophan supplements have been used to treat insomnia and depression.
Semi-essential amino acids
Histidine
Histidine is used to treat allergies, ulcers, anemia, arthritis and high blood pressure.
Nonessential amino acids
Aspartic acid has been used to treat fatigue and depression. Glutamic acid has been used to treat fatigue and alcoholism. Cysteine can be converted to glutathione, which has antioxidant properties and it may be useful in preventing and treating disorders in which free radical damage plays a part. Tyrosine has also been used to treat depression.