What are Non-Essential Amino Acids?

Amino acids are often referred to as the building blocks of protein.

These molecules combine to form important proteins in the body, and they play an important role in metabolism.

Nutritionally, amino acids are categorized as either “essential” or “non-essential.” Keep reading to learn more about the difference between these two types of amino acids. 

What are Amino Acids?

Amino acids are the building blocks of protein.

Proteins are long chains of amino acids arranged in different sequences. The sequence of amino acids determines the shape and function of the protein. 

Amino acids play a role in several processes in the body including digestion, building and repairing tissues (i.e. organs, muscles, bones), making hormones and neurotransmitters, and healthy immune function.

Amino acids can be consumed from protein-rich foods in the diet and from protein or amino acid supplements. 

But what do we mean by essential and non essential amino acids? Let's take a closer look.

Essential vs Non-Essential Amino Acids 

The body needs 20 different kinds of amino acids to function properly.

These 20 amino acids are arranged in different ways to make proteins in your body. Your body can make hundreds of amino acids on its own, but there are 9 amino acids it cannot make.

These 9 are called essential amino acids and the other 11 that your body can produce are called non essential amino acids.

What are Essential Amino Acids 

The 9 amino acids your body cannot make are called essential amino acids.

You have to consume these essential amino acids from the foods you eat.

The 9 essential amino acids include phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine,  and histidine. Each of these amino acids plays an important role in the body. 

  1. Phenylalanine is an essential amino acid converted to the neurotransmitters tyrosine, dopamine, epinephrine, and norepinephrine.

    This amino acid is an important part of the structure and function of proteins and enzymes, and the production of other amino acids.

  2. Valine is another essential amino acid that helps stimulate muscle growth and repair and plays a role in metabolism.

  3. Threonine plays an important role in skin health, fat metabolism, and immune function. It is a significant part of structural proteins, like collagen and elastin, which are important components of your skin and connective tissue.

  4. Tryptophan is needed to make the neurotransmitter serotonin, a chemical that regulates appetite, sleep, and mood. 

  5. Methionine is needed for metabolism and detoxification. The body cannot absorb zinc and selenium without methionine. These essential minerals are vital to your health.

  6. Leucine is needed for protein synthesis and for repairing muscle damage. It also plays a role in regulating blood sugar levels, promotes wound healing, and produces growth hormones.

  7. Isoleucine is highly concentrated in muscle and plays an important role in immune function, hemoglobin production, and metabolism.

  8. Lysine is necessary for building proteins and the production of hormones and enzymes. It's also important for metabolism, immune function, and skin health.

  9. Histidine is used to produce the neurotransmitter histamine, a chemical that has a critical role in the immune response. It also affects digestion, sexual function, and sleep-wake cycles. Histidine is important for maintaining the protective barrier that surrounds your nerve cells, the myelin sheath. 

Now that we've covered the 9 essential amino acids, let's take a closer look at the non essential amino acids.

What are Non-Essential Amino Acids 

There are 11 non essential amino acids that your body can produce on its own.

The non essential amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine. 

Some non essential amino acids are classified as conditionally essential.

Conditionally essential amino acids are non essential amino acids that become essential when you're ill or the body is under stress. 

Conditionally essential amino acids include arginine, cysteine, glutamine, tyrosine, glycine, ornithine, proline, and serine. 

Do We Not Need Non-Essential Amino Acids?

The term nonessential amino acids can be a little misleading. 

Non-essential amino acids do serve an important role in the body to maintain proper functioning, they are just not an essential part of the diet. The body can make non-essential amino acids from essential amino acids when not consumed from the diet. 

When non-essential amino acids are consumed from the diet, they can be converted to glucose which is used for energy. 

In short, yes, your body needs non-essential amino acids to function optimally. 

What Foods are the Best Sources of Amino Acids?

Foods that contain protein are a source of amino acids.

Foods that contain all 9 essential amino acids are called complete proteins. A complete protein is a protein that provides all of the essential amino acids in amounts that adequately meet the body's needs. 

Most animal sources of protein, including meat, poultry, fish, eggs, and dairy, contain all the amino acids your body needs.

Plant-based protein sources, like grains, legumes, vegetables, and nuts, usually lack one or more of the essential amino acids. 

You can still get all 9 essential amino acids by eating only plant foods. You'll need to include a variety of plant-based protein sources to create complementary proteins. Soy is the only plant-based protein that contains all the essential amino acids, however, it is low in methionine. 

Eating plant-based proteins that are complementary to each other can help you get all the essential amino acids without consuming animal products. 

Plant-based protein sources include tofu, tempeh, edamame, lentils, chickpeas, peanuts, almonds, quinoa, chia seeds, beans, potatoes, and leafy greens and vegetables.

Should I Take an Amino Acids Supplement?

If you think you don't consume enough of the foods mentioned above, you may want to consider taking an amino acid supplement. 

While most people can meet their amino acid needs from their diet, some people can benefit from taking an amino acid supplement. 

People who are interested in building muscle often take amino acids. There are other benefits to taking amino acid supplements as well. 

What are the Benefits of Amino Acids Supplements?

While amino acids can be consumed from a wide variety of foods, taking an amino acid supplement has been linked to numerous health benefits.

A daily essential amino acid supplement containing tryptophan may help improve mood. 

Tryptophan is a precursor to the neurotransmitter serotonin which is responsible for mood, sleep, and behavior. Studies have shown that taking an amino acid supplement that contains tryptophan may improve mood and decrease depression. 

Many people take also branched-chain amino acids (BCAAs) to decrease exercise-related fatigue, boost athletic performance, and stimulate muscle recovery. Studies have shown that BCAAs can support muscle recovery and decrease soreness after intense exercise. 

Additionally, research suggests that taking conditionally essential amino acids following surgery may help improve wound healing and recovery. 

Bottom Line on Amino Acids

Amino acids are the sub-units that make up protein. There are 20 amino acids the body needs to function properly.  

Your body can make 11 of these amino acids on its own, but 9 of them are considered essential and need to be consumed from the diet. 

You can consume the essential amino acids from high-protein foods including meat, poultry, fish, eggs, and dairy. Plant-based sources of protein include grains, legumes, vegetables, and nuts, but usually lack at least one of the essential amino acids. 

You may want to take an amino acid supplement if you don't consume enough protein in your diet. Additionally, supplementing with amino acids may improve athletic performance, muscle recovery, mood, and recovery from surgery.