Difference Between Essential and Nonessential Amino Acid

Amino acids are the building blocks of proteins, which are essential macronutrients required by the body for various functions. There are 20 different types of amino acids found in nature, which can be classified into two categories: essential and nonessential amino acids.

What are Essential Amino Acids?

Essential amino acids are those that the body cannot produce on its own and must be obtained through the diet. There are nine essential amino acids, including histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. These amino acids are crucial for protein synthesis, which is essential for muscle growth and repair, immune function, hormone production, and enzyme activity.

Sources of Essential Amino Acid

Essential amino acids cannot be made in the body and therefore need to be taken in with food. The best food to eat that contains these essential amino acids is a protein that is from an animal. In other words, complete protein foods such as eggs, chicken, duck, beef, and so on.

It is possible to be a vegetarian or vegan and still get all your essential amino acids without eating meat. There are, in fact, a few vegetable sources that provide all of the amino acids, for instance, quinoa and soy. Certain protein combinations are known as complementary, and if you combine them, you will get all these amino acids. An example of this is whole wheat bread and peanut butter.

Function of Essential Amino Acid

These amino acids all have important functions in the body. Phenylalanine, for example, is needed to make various neurotransmitters such as epinephrine and dopamine, which are important in the brain. Similarly, the amino acid tryptophan is used to form serotonin in the brain. Valine and leucine are both important in forming muscle and repairing muscle tissue. Connective tissue fibers are formed using the acid threonine. Histidine is the precursor molecule for histamine and functions as part of the immune system along with the amino acid lysine.

Deficiency of Essential Amino Acids

A lack of essential amino acids can have adverse consequences for the immune system resulting in reduced production of antibodies. This would make an individual more susceptible to becoming ill from bacterial or viral infections.

What are Nonessential Amino Acids?

Nonessential amino acids, on the other hand, are those that the body can produce on its own from other amino acids or from other sources such as glucose. There are 11 nonessential amino acids, including alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine. While nonessential amino acids are not required in the diet, they still play a crucial role in various bodily functions.

Sources of Nonessential Amino Acid

Nonessential amino acids can be taken in with food, which is more important for children who are growing rapidly. They can, however, be synthesized in the human body using the parts of carbohydrates and amino acids that are present. The vast majority of these amino acids are formed from alpha ketoacids and by a chemical process that is known as transamination. Transamination is a way in which an amino group is taken from a molecule and added to a ketoacid to form a new and different amino acid.

Functions of Nonessential Amino Acid

These amino acids, although considered nonessential, still play an important role in the human body. They can be used to make other substances, and can even be converted to glucose to provide energy if needed. They are used to make other polypeptides and protein molecules that the body relies on.

Deficiency of Nonessential Amino Acid

Deficiencies in nonessential amino acids are unlikely to occur in a healthy individual provided they are consuming enough protein and carbohydrates every day. There can, however, be problems if a person is ill or in a state of starvation. A deficiency in arginine is particularly common in babies that are born prematurely. This can then lead to problems in detoxifying and eliminating ammonia from their bodies leading to a state of hyperammonemia.

Differences: Essential and Nonessential Amino Acid

One of the most significant differences between essential and nonessential amino acids is that the body cannot produce essential amino acids on its own. This means that we need to consume these amino acids through the foods we eat. Sources of essential amino acids include animal products such as meat, fish, poultry, eggs, and dairy products. Vegetarian sources of essential amino acids include legumes, beans, nuts, and seeds.

Another difference between essential and nonessential amino acids is their role in protein synthesis. Essential amino acids are necessary for the formation of complete proteins. Complete proteins contain all nine essential amino acids and are found in animal products such as meat, fish, poultry, and dairy products. Incomplete proteins, on the other hand, are missing one or more essential amino acids and are found in plant sources such as legumes, beans, nuts, and seeds. While incomplete proteins can still provide some of the essential amino acids needed for protein synthesis, it is essential to consume a variety of protein sources to ensure that all essential amino acids are obtained.

The following table highlights the major differences between Essential and Nonessential Amino Acids:

Characteristics	Essential Amino Acid	Nonessential Amino Acid
Definition	Essential amino acids are those which have to be taken in with food as they can’t be manufactured in the body.	Nonessential amino acids can be made in the body using other amino acids and carbohydrates.
Number	There are 9 essential amino acids out of the total 20 amino acids that are known to exist	There are 11 nonessential amino acids out of the 20 amino acids that are recognized.
Sources	Essential amino acids can be taken in through eating animal protein such as eggs and meat, and through eating vegetable sources like soy and quinoa.	Nonessential amino acids can be made in the body from other acids and carbohydrates.
Function	The role of essential amino acids includes building and repairing muscles, and forming neurotransmitters for the nervous system.	The role of nonessential amino acids includes making other substances that are needed and in providing energy.

Conclusion

A deficiency of essential amino acids can result in a weakened immune system and lack of neurotransmitters in the brain. In contrast, a deficiency of nonessential amino acids is rare, but it can occur during starvation or an illness; in premature infants, it can cause too much ammonia to build up.