Essential and Non-Essential Amino Acids

Being an important ingredient of a diet, protein aids in-

• Constructing strength and muscles
• Repairing cells
• Supporting growth

Being the molecules, amino acids are responsible for the formation of proteins. Both amino acids and proteins are the building blocks of life. Amino acids, being the organic compounds, are responsible for the build-up of proteins. Based on the body’s capability to blend proteins, there are two types of amino acids-

• Essential amino acids
• Non-essential amino acids

Amino acids are used to make proteins in order to aid the human body in the following-

• Growing
• Repairing tissue
• Breaking down food into the simplest forms
• Enhancing energy

Classification of amino acids-

• Essential amino acids
• Non-essential amino acids
• Conditional amino acids

Essential Amino Acids

Essential amino acids are not produced in the body. So, they need to be taken in through the food ingested. The best food which consists of essential amino acids is a protein that comes from animals. Examples of complete protein foods are eggs, beef, chicken, duck, etcetera. Being a vegetarian, people could also intake essential amino acids without eating meat as they could get it from a few vegetable sources which provide all of the amino acids like quinoa or soy. There are few ways to get all of the amino acids by executing protein combinations which are known as complementary. For example, whole wheat bread when eaten along with peanut butter forms a perfect protein combination. Essential amino acids are also called indispensable amino acids because the human body is deficient of the metabolic pathways required to synthesise amino acids.

Classification of Essential Amino Acids

• Histidine
• Isoleucine
• Leucine
• Lysine
• Methionine
• Phenylalanine
• Threonine
• Tryptophan
• Valine

There are various important roles played by an essential amino acid. Phenylalanine is used to make various neurotransmitters like epinephrine and dopamine which are important for the brain. Tryptophan is an amino acid which is used to form serotonin in the brain. Valine and Leucine are used to form muscle and repair muscle tissue. Connective tissue fibres are formed by using the acid threonine. Histidine is the precursor molecule for histamine which acts as part of the immune system along with the amino acid lysine.

Deficiency of essential amino acids could lead to

• Unpleasant consequences of the immune system resulting in reduced production of antibodies
• Increased susceptibility to falling sick from bacterial or viral infections

Non-essential amino acids

Non-essential amino acids are produced in the body itself. So, none of it comes from the diet. Out of 20 amino acids known to all, 11 are non-essential which benefits the body by expelling toxins from it. Non-essential amino acids are also called dispensable amino acids because the human body is capable of synthesizing using only the essential amino acids. The non-essential amino acids play a vital role in the human body by making other substances and even converting those to glucose in order to provide energy when required. They are used to make other polypeptides and protein molecules which the body depends upon.

Classification of Non-Essential Amino Acids

• Alanine
• Arginine
• Asparagine
• Aspartic acid
• Cysteine
• Glutamic acid
• Glutamine
• Glycine
• Proline
• Serine
• Tyrosine

Synthesis of non-essential amino acids take place in the body itself while essential amino acids are obtained from the diet. The cells of the human body provide the carbon skeleton of the non-essential amino acids which comes from intermediates of the glycolytic pathway and Citric Acid Cycle (Tricarboxylic Acid Cycle or the Krebs Cycle). The Alpha amino group is attached by enzymatically catalyzed transamination of pre-existing amino acids. Non-essential amino acids are formed from-

• Phosphoglycerate or 3-phosphoglyceric acid
• Pyruvate or Pyruvic acid
• Oxaloacetate or oxaloacetic Acid
• Alpha-ketoglutarate or Alpha-ketoglutaric acid

Deficiency of non-essential amino acids

Deficiency in arginine is common in premature babies. This could lead to a state of hyper ammonia which means problems in detoxifying and eliminating ammonia from the body.

Differences between Essential and Non-Essential Amino Acids

An essential amino acid cannot be produced in the body but has to be taken in from food whereas a non-essential amino acid is produced in the body from carbohydrate and protein molecules. Essential amino acids work to build muscle tissues and repair them. They produce precursor molecules in order to form neurotransmitters in the brain. While non-essential amino acids work to add in the functioning of the brain as well as remove toxins from the body. They also synthesise Red Blood Corpuscles (RBCs) and White Blood Corpuscles (WBCs) effectively.

Conclusion

Overall, an essential amino acid is not produced in the body unlike the non-essential amino acids which are made in the body from Carbohydrate and protein molecules. So, essential amino acids need to be taken in from dietary food. The human body needs all of the amino acids so that the body can build a wide variety of proteins it needs. Proteins are needed for repairing, growth and maintenance of the cell. Out of the 20 amino acids, 9 are essential while 11 are non-essential amino acids.