The amino acid leucine is one of the essential amino acids required in the diet as it is not synthesized in the body. Structurally it is one of the amino acids with branched side chains - the others being the amino acid isoleucine and the amino acid valine. All the three amino acids with branching side chains work together inside the body and protect muscle or act as fuel in the biochemistry of the body. These branched side chain amino acids promote healing in the bones, the skin and the tissues of the muscles - as such, they are all normally recommended for people recovering from surgery, as they tend to increase the rate of healing in the body. The synthesis of growth hormone is also promoted by leucine - this amino acid also lowers the elevated levels of sugar in the blood. All supplements of L-leucine should ideally be balanced with supplements of L-isoleucine and L-valine at the same time. Supplementation must also be done in moderation as excess amounts can induce physical symptoms akin to hypoglycemia in the patient. High levels of leucine supplements may also lead to disorders such as pellagra, excessive levels of leucine can also increase the total amount of ammonia found in the body of a person. As has been mentioned, the amino acid leucine belongs to the class of branched chain amino acids - in common with the amino acids valine and isoleucine. Almost seventy per cent of all the amino acids found in the proteins of the human body are these three branched-chain amino acids - supplements of these three amino acids are usually taken in combination form. It is impossible to quantify the actual value of these three branched amino acids in the formation and maintenance of proteins and their role in the structural and functional integrity of proteins is very important. A starving person, those affected by stress, by acute or chronic infection or those recovering from physical trauma bounce back from a weakened state as the body mobilizes leucine as the primary source in the process of gluconeogenesis - which is the synthesis of blood sugar in the liver. This action hastens the healing process and supplies the body with much needed energy in the form of sugar. The beneficial role of leucine and its possible therapeutic effects on the prevention of wasting of protein in the body, during starvation, semi-starvation, physical trauma or recovery from surgery has recently been speculated and required further study. Poor utilization of leucine for example has been linked to the deficiency of the sugar regulating hormone insulin. A higher intake of leucine may therefore be required by all individuals suffering from disorders such as glucose intolerance. Anabolic effects possessed by leucine has also recently been speculated; the amino acid is thought to be responsible for the prevention of muscle protein degradation and is believed to be useful in stimulating the synthesis of proteins in the muscles. Good natural sources of leucine includes foods such as brown rice and beans, all types of meats and poultry, items like nuts, whole wheat and soy flour.