Difference Between Essential and Non-essential Amino Acids

Essential vs Non-essential Amino Acids

Amino acids are the building blocks or precursors of proteins. As the name implies, amino acid contains amino group (-NH2) and an acidic carboxyl group (-COOH). With these two groups, an additional hydrogen and a functional side chain (R group) are bonded to a central carbon atom. The nature of this R group determines the unique characteristics and the chemistry of the amino acid, thus resulting in various proteins. Proteins are the most diversified group of macromolecules, both chemically and functionally. Amino acids act as a source of energy under certain conditions in the body. Also, amino acids are involved in the detoxification of drugs, chemicals, and metabolic products. They can also act as precursors of neurotransmitters, peptide and thyroid hormones, histamine, NAD etc. There are 20 different amino acids linked via polypeptide bonds, to make various proteins. The amino acid sequence determines the structure and function of the protein.

All twenty amino acids are essential for every organism. A lack of any amino acid leads to severe metabolic disruption in the body.

Essential Amino Acids

Most plants and microorganisms are capable of synthesizing all 20 amino acids on their own from glucose or CO2 or NH3-. During the process of evolution, mammals, including humans, have lost the ability to synthesize the carbon skeleton for several of the amino acids. Therefore, it is essential to obtain these particular amino acids through the diet. Those amino acids that cannot be synthesized in the body, to meet the demand required by the body, are known as ‘essential amino acids’.

There are 09 essential amino acids required for the human body, namely; phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, histidine, lysine, and leucine. Since animal flesh is a complete source of essential amino acids, non-vegetarians need not be too concerned about a balanced diet, but those who do not eat animal products must be concerned about the essential amino acids as the body cannot synthesize certain basic proteins without these amino acids.

Nonessential Amino Acids

Non-essential amino acids are the amino acids that can be produced in our body. Even though we can obtain these amino acids through our diets, the human body can still synthesize these particular amino acids. These non-essential amino acids are Alanine, cysteine, cystine, glutamine, glutathione, glycine, histidine, serine, taurine, asparagine, apartic acid, and proline.  Although the non-essential amino acids are readily available in the human body, they can also be obtained from the foods like nuts, grains, meats, fruits and vegetables.

What is the difference between Essential and Non-essential Amino Acids?