Amino acids are the foundation of life. They are involved in everything from building muscle and life-supporting tissues to making the chemicals necessary for our brain and vital organs to function. Beyond serving as the building blocks for all-important proteins, amino acids are in and of themselves important signaling factors and intermediaries in many metabolic pathways.

The average human body is 60-70% water while protein constitutes two-thirds of the non-water component of the body. We can all appreciate how important it is to drink plenty of fluids in order to balance the water lost through sweat, urine, and respiration. But we also lose protein on a daily basis as muscles and tissues degrade and amino acids are oxidized. Just as it’s important to rehydrate with water, a significant dietary input of amino acids is required to maintain this body pool at an optimal level. These requirements are even greater under conditions that affect our overall diet quality and subject us to a variety of physiological stresses.

Amino Acids in Balance

Every amino acid can serve as a structural component of protein, skeletal muscle being the main reservoir in the human body. Individual amino acids have unique functions, such as arginine’s role in the production of nitric oxide or leucine’s action on initiating the process of protein synthesis. However, it is an oversimplification to expect a specific outcome in response to taking a single amino acid supplement.

When a specific action is attributed to an amino acid, it is in the context of the whole body chemistry and all amino acids working together. For example, it seems reasonable to consume arginine to stimulate nitric oxide production since that is what arginine does in the body. Yet arginine supplements do not cause a large increase in arginine concentrations in the blood and tissues because much of the orally ingested arginine is taken up and metabolized in the liver. It is more effective to take a citrulline supplement which is converted to arginine in the kidneys, thus making arginine available to circulate to endothelial cells and other tissues.

Just like the way in which many vitamins function, taking more of a single amino acid does not necessarily create more of an effect, and often it is only with a deficiency of the nutrient that a problem arises. Isolated amino acid deficiencies are very rare and usually attributable to metabolic defects.

Amino acids function as a team in a physiological system with many other compounds and factors that affect how it operates. To keep amino acids in balance, eat a varied protein- and antioxidant-rich diet.