Essential Amino Acids: Biology’s Lego Bricks
Proteins are important for a healthy and balanced diet. Proteins are also important for almost all biological processes of our body and it comprises amino acids. But what are amino acids? Read on to know about essential amino acids, essential amino acids foods and benefits.
The proteins which we consume in our diet are broken down into smaller units known as amino acids. Amino acids are the Lego Bricks of the biological system. Different amino acids chemically associate with each other to form proteins. Even our body arranges amino acids in many combinations, to make thousands of different proteins from just 21 amino acids.
Amino Acids: A Brief Introduction
A human body can take apart the amino acid building blocks that make up a certain protein and re-use these to make new, different proteins. Even your body knows to recycle, isn’t it really cool!
Amino acids join to form short polymer chains called peptides or longer chains called either polypeptides or proteins. Amino acids are an important pillar of metabolic processes occurring in our body. Majority of diseases affecting us can be linked to certain metabolic disruptions.
Essential Amino Acids
There are 21 amino acids that make up all the proteins in our body. These amino acids can be classified into two groups, “essential amino acids” and “non-essential amino acids”. Essential amino acids are amino acids which cannot be synthesized by the human body and therefore should be present in our day-to-day diet.
There are nine amino acids which the human body cannot produce and are thus referred to as “essential”. These are phenylalanine, threonine, valine, tryptophan, methionine, leucine, isoleucine, lysine and histidine. Proteins which contain all of these nine essential amino acids are called complete proteins whereas others are called incomplete proteins.
Essential Amino Acids Classification
Let’s find out how these essential amino acids affect our health and why are they so important.
It is an important amino acid as it has analgesic and antidepressant actions, and is present in breast milk. Foods containing phenylalanine are milk, eggs, chicken, beef, liver, and beans.
Threonine plays a critical role in the maintenance and growth of the intestinal mucous membrane. Additionally, it helps to treat various nervous system disorders including spinal spasticity, multiple sclerosis and ALS (Amyotrophic Lateral Sclerosis). Foods containing threonine are cottage cheese, poultry, fish, meat, lentils, black turtle beans and sesame seeds.
Valine is an important source of nitrogen and it helps in tissue repair and immune system regulation. A protein-restricted diet can reduce valine blood levels and decrease fasting blood glucose levels. Important sources of valine are meats, soy products, beans, and legumes.
Tryptophan is a precursor to the neurotransmitter serotonin and the hormone melatonin. Serotonin is the body’s natural mood stabilizer and has various functions across the body. On the other hand, melatonin regulates the body’s sleep-wake cycles. Tryptophan intake can also help cure sleep disorders, anxiety, and headaches.
Additionally, it reduces stress by increasing serotonin levels in the blood and helps to maintain a healthy weight. Some tryptophan amino acids foods are eggs, bananas, raw dairy products, whole grains, beans, legumes, etc.
Methionine helps in the growth of new blood vessels. It acts as a precursor of carnitine (a substance that helps convert fats into energy) and also helps the liver inefficient fat processing. Main sources of methionine are fish, meats, eggs, sesame seeds and other plant seeds. Methionine consumption should be monitored carefully as overconsumption can lead to cancerous growths.
Leucine intake in diets enhance muscle growth and muscle strength, stabilize blood sugar levels as well as control wasting away of muscles in older individuals. Some leucine amino acids foods are cheese, chicken, parsley, peanuts, fish and other seafood.
Isoleucine promotes the synthesis of haemoglobin and other essential proteins, detoxification of nitrogen wastes as well as wound healing. Its deficiency can cause vision disturbances, dermatitis, and diarrhoea. Some isoleucine rich foods are fish, meats, legumes, seeds and many more.
Lysine is important for the synthesis of collagen (a protein) and carnitine and other proteins. In addition, it also helps in calcium absorption. Lysine deficiency can cause symptoms like nausea, agitation, fatigue, anaemia and even impaired growth. Some lysine amino acids foods are lentils, spinach, poultry, green beans and nuts.
Histidine can help in curing rheumatoid arthritis, ulcers, anaemia and other allergic diseases. It helps in the synthesis of haemoglobin, tissue repair as well as strengthens the immune system. Moreover, it is the building block of many iron-containing compounds such as ferritin. Lack of this amino acid can lead to slower healing of wounds, impaired growth, and skin inflammation. Some foods rich in histidine are legumes, salmon, soybeans, chicken, pork, beef, and cheese.
Thus, we saw how important these essential amino acids are for our health. Complete proteins provide the body with all these amino acids. Animal proteins such as meat, poultry, fish, seafood and eggs are generally considered complete proteins. On the other hand, milk and milk products such as yoghurt, cheese as well as non-dairy milk substitutes such as soy milk are good sources of complete proteins for vegetarians. Moreover, mixing and combining multiple incomplete proteins can also meet the body’s daily essential amino acid requirements.
However, the story does not end here. Besides their name, non-essential amino acids also have a variety of important roles in the human body. Did you know that one non-essential amino acid also functions as a neurotransmitter which has critical roles in memory, learning, and even intelligence? Know more about non-essential amino acids and how important they are to us here.