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Amino Acids: What Are They, Their Importance, Types Of Amino Acid & More


Making its way out of science textbooks, “amino acids” is a term known by a layman.

However, its growing relevance in the health sector and the hundreds of new studies regarding it are enough to attract a much-needed attention.

Amino acids are an inseparable part of healthy human life. The body’s building blocks, i.e., proteins, cannot be made without amino acids.

Additionally, they lend a helping hand in the absorption of nutrients and repairing damaged tissues. These are only some of the benefits of amino acids.

Having said all that, through this article, we will try to explore everything from basics to the topics that are not talked about enough.

If you want to know more about amino acids and get answers to your questions, go through it till the end.

What Are Amino Acids?

They are given the name amino acids because they contain the amino group NH2 which is attached to a chain of carbons. It also has a carboxylate ion.

The presence of the term acid here, however, doesn’t signify that all the types of amino acids are acidic. They have a varying range of pH.

The pH of a given amino acid can range anywhere from 5 – to 11.5. They can be acidic, neutral, or basic. Their biggest role is in protein synthesis.

They combine to form proteins and then are broken down into amino acids again in our body for digestion purposes.

The amino acids get transported via the blood and could be used for energy purposes. Thus, the most common[1] method of amino acid intake is through food.

Amino Acids

Why Are Amino Acids Important For Health?

Without any doubt, it is very important to consume amino acids for a healthy life. They are very important[1] for protein synthesis.

It is the fundamental unit of proteins which are the fundamental unit of the body. Without proteins, it is difficult to imagine human existence.

But keeping this building block factor aside, there are many other important functions amino acids have to perform.

They are one of the factors that contribute to maintaining the pH balance of the blood. When the pH is low i.e. acidic they take H+ ions and when it is high, they give H+ ions. Thus, they act as a buffer in the blood.

They are also the storehouse of nitrogen. Amino acids have a key role to play in the urea cycle. Cellular growth and tissue repair also fall under protein dependent functions.

They are extremely important for brain function since tryptophan is related to the production of neurotransmitters. Branched-chain amino acids are related[2] to post-surgical recovery.

Amino acids are generally believed to have an anti-inflammatory effect which can be very useful for the bodybuilding industry as a whole.

They also regulate the secretion of a few hormones like thyroxine and insulin. Glycine may act as a sleep coordinator fetching some extra hours of quality sleep.

Another vital role of amino acids in compound formation. Phenylalanine has a contributory role in melanin synthesis.

It is the pigment that is responsible for giving color to eyes and skin. Histidine assists in the formation of histamine. It also has a role in the formation of red and white blood cells.

Types Of Amino Acids

They can be categorized into

  1. Essential Amino Acids

    They are the ones that cannot be produced by the body and have to be included in the diet.

    Though not produced by the body, they[3] are very important for the healthy functioning of the body. There are 9 such amino acids.

    They are

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


      All of them have a general and specific function to play.

  2. Non-Essential Amino Acids

    They are produced by the body. Therefore, there is no need for dietary intake. That’s the reason behind their naming.

    The tag “non-essential” signifies that it is produced by the body and not to be taken through diet. However, it is misunderstood by some to be unimportant.

    This is not true. They are equally vital for human[4] survival. They are 11 in number. Namely,

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


  3. Conditionally Essential Amino Acids

    They are normally not essential and are a part of the non-essential subcategory.

    But, at some particular point like after an illness, injury, stress, any other medical condition, or during infancy, the body is not able to produce an adequate amount of these.

    Therefore, they are to be taken[3] through the diet. 6 amino acids are considered conditionally essential.

    These are

    • Arginine[5]
    • Cysteine
    • Glycine
    • Glutamine
    • Proline
    • Tyrosine

Amino Acid Disorders

Amino acids are quite essential in one’s body to help with protein metabolism.

However, if the metabolism of any amino acid is somehow disrupted, and it cannot be produced or broken down properly, this can lead to the development of serious conditions.

  1. Phenylketonuria

    This[6] is a disorder in the human body where phenylalanine hydroxylase is less active.

    Due to this amino acid phenylalanine is not converted into tyrosine which further acts as a major factor in the working of a few hormones, skin, hair, and eye pigments too.

    The increased concentration of phenylalanine in the bloodstream can cause seizures and behavior disorders.

  2. Tyrosinemia

    Tyrosinemia is caused by another enzyme deficiency[7] and low levels of fumarylacetoacetate hydrolase.

    Tyrosinemia can further cause liver disease, kidney defects, weight gain, and peripheral nerve disorder. The affected patients are also at an increased risk of developing liver cancer.

    A low protein diet and vitamin C therapy can help patients with tyrosinemia.

  3. Homocystinuria

    Homocystinuria is a disorder which occurs as a result[8] of defective cystathionine beta-synthase which helps in the metabolism of methionine.

    This defect can cause damage to the lens, osteoporosis, and intellectual and psychiatric disorders.

    Usually, homocystinuria can be managed well with vitamin B and folic acid alongside a few dietary restrictions.

  4. Nonketotic Hyperglycinemia

    Nonketotic hyperglycinemia can cause seizures, hiccups, and breathing problems with developmental impairments, as per the government research[9].

    The heavy concentration of neurotransmitter glycine in the nervous system is the reason behind this disorder because  there are dysfunctional enzymes which fail to split amino acid glycine.

    As of now, there is no cure for this disorder but medications and a low protein diet can ease the symptoms.

  5. Urea Cycle Disorders

    Nitrogen containing waste is disposed of in the urea cycle with the help of liver cells. Normally, ammonia nitrogen is split off in the cycle and then passed out through urine.

    But any defect[10] occurring in any enzyme during the urea cycle can cause serious problems by the accumulation of toxic ammonia in the blood.

    This toxic ammonia could cause vomiting, lethargy, and even coma.

Problems Due To Amino Acids Deficiency

It is clear from the above-provided information that amino acids have a big role to play in the healthy existence of humans.

Any problem with amino acid metabolism can cause numerous[11] health problems. The reason for the deficiency can be poor diet, stress, amino acid and genetic disorders, the latter of which we mentioned above.

For non-essential amino acids, low production in the body itself could be the biggest cause. Let us look at some of the possible consequences of this deficiency

  1. Digestive Issues

    Amino acids are formed in the body when proteins are broken down into simpler substances.

    They are then transported to various body parts. However, if there is a deficiency a there could be digestive problems.

  2. Low Immunity

    As discussed above, histidine[3] has a role in the formation of red and white blood cells.

    Its deficiency may affect their production which will affect their immunity. Your body might become an easy target for infections and viruses.

    Not just because of RBC and WBC, but any sort of deficiency is sure to affect the nutritional status of the body. This can be the cause of hindrance in the sound immune system.

  3. Neurological Disorder

    Tryptophan is related to neurotransmitter production. Its deficiency can affect the healthy thought process and functioning of the brain.

  4. May Cause Premature Death

    Several cases are reported every year where newborns die due to amino acid deficiency diseases.

    Moderate deficiency can cause fatigue and nutritional deficiency.

  5. Affects The Skin

    Amino acids are very important for healthy skin as they provide moisture to the skin.

    Some researchers say that they may even slow down aging by preventing free radical damage.

    Their deficiency could cause skin issues and speed up the aging process.

  6. May Affect Fertility

    Amino acids are a big part of seminal plasma and motility of sperms. Their absence may affect the healthy reproductive capacity of males.

    Even in females, amino acids may help to eliminate reproductive disorders and boost fertility. Their deficiency may affect fertility negatively.

Ways To Consume Amino Acids

The most common way of intake is the dietary method. A healthy diet provides all essential amino acids.

You can opt for complete proteins for a balanced intake. A healthy individual with a balanced diet doesn’t need any supplement until it is for a specific reason.

Consultation is still important. Amino acids can be consumed in the form of liquid supplements[12] and powders as well.

Foods Rich In Amino Acids

Complete proteins are good sources with all the essential amino acids available in them in some adequate proportions[13].

These are generally animal-based. Some of them are-

  • Eggs
  • Red meat
  • Pork
  • Beef
  • Seafood
  • Cheese
  • Milk

Food Source Of Amino Acids For Vegans

It is not a difficult task for vegans to find amino acids.

A combination of these foods listed below can be distributed in meals for daily consumption to get enough protein and avoid overeating.

Some of them are-

  • Whole grains
  • Nuts like almonds, walnuts,  pistachios
  • Legumes[14] like lentils, chickpeas,  black beans
  • Veggies like broccoli, peas


Amino acids are one of the necessities for healthy existence. Not only are they the building blocks of proteins, but also have other functions to perform.

They are good for the gut, skin, and brain. Their absence can lead to numerous health problems.

It may cause infertility, speed up the aging process and even cause the death of newborns.

Though there are fatal consequences, people are mostly unaware of these. Therefore, it is very important to follow a balanced diet.

Normally, for a healthy individual, a balanced dietary intake is sufficient.

+14 References/Sources

Working4Health prefers using primary and verified references. We have strict sourcing guidelines and our primary references include peer-reviewed research, academic, and medical institution studies.

  1. Amino acids Available from: https://medlineplus.gov/ency/article/002222.htm
  2. Robert R. Wolfe Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017; 14: 30.
    Published online 2017 Aug 22. doi: 10.1186/s12970-017-0184-9
  3. Michael J. Lopez; Shamim S. Mohiuddin. Biochemistry, Essential Amino Acids Last Update: March 18, 2022.Available from: https://www.ncbi.nlm.nih.gov/books/NBK557845/
  4. Meerza Abdul Razak, Pathan Shajahan Begum, Buddolla Viswanath, et al. Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review Oxid Med Cell Longev. 2017; 2017: 1716701. Published online 2017 Mar 1. doi: 10.1155/2017/1716701
  5. Marc P. McRae Therapeutic Benefits of l-Arginine: An Umbrella Review of Meta-analyses J Chiropr Med. 2016 Sep; 15(3): 184–189.
    Published online 2016 Sep 10. doi: 10.1016/j.jcm.2016.06.002
  6. William L. Stone; Hajira Basit; Evan Los. Phenylketonuria Last Update: May 9, 2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK535378/
  7. Lisa Sniderman King, Cristine Trahms, and C Ronald Scott. Tyrosinemia Type I Last Update: May 25, 2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1515/
  8. Stephanie J Sacharow, Jonathan D Picker, and Harvey L Levy. Homocystinuria Caused by Cystathionine Beta-Synthase Deficiency Last Update: May 18, 2017. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1524/
  9. Johan LK Van Hove, Curtis Coughlin, Michael Swanson, et al. Nonketotic Hyperglycinemia Last Update: May 23, 2019. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1357/
  10. William L. Stone; Hajira Basit; Gayatri B. Jaishankar. Urea Cycle Disorders Last Update: May 9, 2022. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482363/
  11. Lysinuric protein intolerance Available from: https://medlineplus.gov/genetics/condition/lysinuric-protein-intolerance/
  12. Francesco S. Dioguardi Clinical use of amino acids as dietary supplement: pros and cons J Cachexia Sarcopenia Muscle. 2011 Jun; 2(2): 75–80. Published online 2011 Jun 11. doi: 10.1007/s13539-011-0032-8
  13. Hanna Górska-Warsewicz, Wacław Laskowski, Olena Kulykovets, et al. Food Products as Sources of Protein and Amino Acids—The Case of Poland Nutrients. 2018 Dec; 10(12): 1977. Published online 2018 Dec 13. doi: 10.3390/nu10121977
  14. Marina Carbonaro1, and Alessandro Nucara Legume Proteins and Peptides as Compounds in Nutraceuticals: A Structural Basis for Dietary Health Effects Nutrients. 2022 Mar; 14(6): 1188. Published online 2022 Mar 11. doi: 10.3390/nu14061188

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