Leucine:

Leucine is readily available in good concentrations in animal protein foods (poultry and red meats) and dairy products; wheat germ and oats also contain leucine. It is essential for growth, as it stimulates protein synthesis in muscle. Leucine may help produce energy, as can isoleucine and valine, the other branched-chain amino acids during periods of fasting or starvation. A deficiency of leucine can cause a biochemical malfunction producing hypoglycemia in infants. Leucine is also helpful in Tissue Repair.