Proteins and Amino Acids

Amino acids are the building blocks of proteins. Various numbers of amino acids held together in diverse sequences result in proteins with different characteristics. The protein in hair, for instance, has a particular sequence of amino acids, and the protein in muscle has another sequence of amino acids. When proteins are broken apart, the result is a pool of amino acids derived from the amino acid building blocks of the protein.

Many athletes consume protein or amino acid supplements, believing they promote muscle building. However, dietary assessments of athletes strongly suggest that any benefit of the supplement comes from helping athletes meet their caloric needs rather than independently supporting a larger muscle mass. Because this is most likely the case, most athletes would find it easier, cheaper, and safer to eat more food to obtain the needed calories than to take the protein or amino acid supplements. Studies generally agree that humans use, anabolically, only about 1.5 grams of protein per kilogram of body weight.^36,37 Protein requirement can be thought of as directly related to the amount of fat-free mass a person has, plus a very small amount used to supply energy. Taken together, this amounts to a requirement range for athletes between 1.0 and 1.5 grams per kilogram of body weight. Consuming more than this amount ensures that the remaining protein will be catabolized as a source of fuel or stored as fat. Burning protein as a source of fuel is undesirable because it creates toxic nitrogenous waste (e.g., ammonia, urea) that must be excreted. This mandatory urinary excretion causes an increase in water loss and increases the chance for dehydration.