The amino acid valine cannot be synthesized in the body and is required in the diet. It is therefore considered to be an essential amino acid, as it must be supplied from an outside source. Metabolism in the muscles requires the presence of the amino acid valine. This amino acid is also essential for purposes of tissue repair and restoration. It also plays an essential role in the maintenance of a proper balance of nitrogen in the human body. Muscle tissues contain the highest concentrations of valine - it is found in abundance in the proteins that constitute muscles. Valine can be utilized as a source of energy by the tissues of the muscles as it is one of the branched side chain amino acids. The type of severe amino acid deficiency induced by long term drug addiction can be alleviated with supplements of valine. The consumption of L-valine in supplements must occur in conjunction and balanced with the simultaneous consumption of the other branched side chain amino acids, such as the L-isoleucine and the L-leucine. Tissues repair and restoration is hastened by the amino acid valine. The myelin covering of neurons may be negatively affected by a deficiency of the amino acid valine in the body. Good food sources of the amino acid valine include various grains, all kinds of dairy products - cottage cheese in particular, foods like mushrooms, poultry and meats, peanuts and soy proteins.