Amino acids

        Amino acids are organic compounds that combine with each other to form proteins, according to the National Institutes of Health (NIH). There are about 20 amino acids that regularly make proteins and they can be arranged in thousands of different ways. There are three types of amino acids: essential, non-essential and conditional.

      Essential amino acids cannot be made by the body, out of the materials ordinarily available, at a speed that can meet the demands for normal growth; they must be provided preformed in the diet, according to the American Journal of Public Health (AJPH). There are nine essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. A food that contains all nine is considered a complete protein.