Definition of Essential Amino Acids

Amino acids are the smallest units of proteins. Amino acids are organic molecules consisting amine and carboxylic acid functional groups. An amino acid contains nitrogen, carbon, oxygen, and hydrogen molecules.

Essential amino acids, also called limiting amino acids, are amino acids that can not be produced in our body, and that must be obtained from food sources.

There are 8 essential amino acids, which are listed below. Arginine is a conditional essential amino acid, since the body does not produce it at infancy and also in adulthood in certain poor health conditions.

Functions of Essential Amino Acids

Amino acids are required in a variety of metabolisms and are essential components of cells. Even though, some roles can be highlighted as functions of the amino acids, it is important to be aware that they are part of complex biological processes and the body.

Besides, the functions and uses of an amino acid are dependent on other amino acids, mineral elements, carbohydrate and fatty acids. And there fore, they have indirect effects that are manifested in myriad metabolisms.

Our knowledge of the functions of amino acids is ever evolving. And the functions mentioned below are just a few of them.

List of essential amino acids and examples of their functions:

Tryptophan is neecessary for the synthesis of neurotransmitter serotonin. It helps releive migraine and depression. (See here for food sources of tryptophan and its recommended daily allowances (RDA).)

Tyrosine is a precursor of dopamine, norepinephrine and adrenaline. It enhances positive mood. It is also an antioxidant.

Valine is essential for muscle development. Side effects of high levels of valine in the body include hallucinations.

Isoleucine is necessary for the synthesis of hemoglobin, a major constituent of red blood cells.

Leucine is beneficial for skin, bone and tissue wound healing. It promotes growth hormone synthesis. (See here for list of Leucine rich foods and leucine recommended daily allowances (RDA).

Lysine is a component of muscle protein, and is needed in the synthesis of enzymes and hormones. It is also a precursor for L-carathine which is essential for healthy nervous system function. See here for high lysine food sources and lysine recommended daily allowances (RDA).

Methionine is an antioxidant. It helps in breaking down of fats and aids in reducing muscle degeneration. It is also good for healthy skin and nail.

Phenylalanine: Beneficial for healthy nervous system. It boosts memory and learning. It may be useful against depression and suppressing appetite. More on phenyalanine (health benefits, side effects, list of foods containing phenylalanine)

Related:

Non-essential amino acids: what are they and their functions