Of the 250 amino acids found in nature, the human body requires 21 of them for growth, health and maintenance. Amino acids are organic compounds that play central roles in the makeup of proteins and act as intermediaries in metabolism. Proteins, necessary to support life and to repair and regenerate cells, consist of a chain of amino acids strung together and folded into complex shapes. Proteins can be structural, such as the keratin in our fingernails or actin, a protein found in our muscles. Proteins can also function as biochemical catalysts and perform critical roles in processes such as neurotransmitter transport. When you take away water, 75% of our bodies consist of amino acids in the form of protein, including all muscles, tissues, cells and body fluids, except urine and bile.
All of these proteins require the correct amino acids, some of which can be found in our bodies. In fact, the human body produces 10 of the 21 amino acids we require on a daily basis. The amino acids that the body cannot produce must be obtained through the foods we eat. These 21 amino acids are classified as essential and nonessential. Nonessential amino acids are those that the body manufactures from the normal breakdown of proteins.
The nonessential amino acids and their roles in the human body:
- Alanine – Alanine helps convert glucose into energy, supports healthy glucose levels, and helps the liver process and eliminate toxins.
- Serine – Serine assists in the function of the central nervous system and general brain function. It aids in the production of antibodies and immunoglobulin, essential to a healthy immune system. Combined with tryptophan, serine helps create serotonin, which regulates mood, depression and anxiety. In order for the body to produce serine, folic acid, vitamin B3 and vitamin B6 must be present.
- Aspartic acid – Aspartic acid helps to keep the brain alert and removes harmful toxins from the liver. It supports proper and efficient metabolism function.
- Cysteine – L-cysteine promotes the health of the stomach lining and aids in the absorption of essential nutrients from foods.
- Glutamine – Glutamine helps to improve mental function, control blood sugar levels, and maintain muscle mass. Glutamine is the most common amino acid found in muscle tissue. When stressed, the body may draw glutamine from the muscles to bolster the immune system. Because of this, bodybuilders often supplement with glutamine in order to maintain good muscle health.
- Asparagine – Created by the liver to support the nervous system, asparagine helps maintain emotional balance and aids fatigue resistance.
- Glycine – L-glycine has an anti-inflammatory effect. It supports proper brain function by encouraging the production of essential neurotransmitters and enzymes. L-glycine is believed to directly affect brain chemistry and processes and is thought to help reduce stress and anxiety.
- Glutamic acid – Glutamic acid is a neurotransmitter that supports the nervous system. It aids in the metabolism of sugars and fats and the detoxification of ammonia from the brain.
- Proline – Proline helps maintain healthy skin and underlying connective tissue such as collagen and cartilage. It assists in breaking down proteins allowing for the formation of new cells.
- Tyrosine – Tyrosine plays a significant role in metabolism and is a precursor to neurotransmitting brain chemicals. It supports hormone production of the thyroid, pituitary, and adrenal glands. Tyrosine is necessary for the synthesis of serotonin, dopamine, epinephrine and norepinephrine.
- Arginine – Arginine plays an important role in expanding blood vessels to facilitate blood flow. It aids in eliminating excessive ammonia from the body and enhances immune function.
- Ornithine – Ornithine is metabolized during urea production and is a precursor to citruline, proline and glutamic acid.
Essential amino acids are not more important to life than nonessential amino acids, but they cannot be synthesized (produced) by the body and must be consumed daily as our bodies do not store them.
Essential amino acids for adults and their functions:
- Isoleucine – Isoleucine is required for the regulation of blood sugar and the formation of hemoglobin, which carries iron in the blood.
- Leucine – Leucine controls the body’s ability to process protein, vitamins and minerals. Without it, your body cannot properly absorb the protein and vitamins you consume.
- Methionine – Methionine is an intermediate in the biosynthesis of cysteine, carnitine and phosplatidylcholine and other phospholipids.
- Phenylalanine – Phenylalanine plays a key role in the biosynthesis of other amino acids and is important in the structure and function of many proteins and enzymes. It is converted to tyrosine and used in the biosynthesis of dopamine and norepinephrine neurotransmitters.
- Threonine – Threonine supports the immune system by aiding the production of antibodies. It is required in the formation of tooth enamel, and collagen and elastin, which are responsible for healthy skin and wound healing.
- Valine – Valine is involved in glucose metabolism and regulation of the immune system.
- Lysine – Lysine assists in the formation of carnitine which converts fatty acids to energy and helps form the collagen needed for connective tissue and bones.
- Histidine – The body uses histidine to produce histamine and for carnosine biosynthesis.
The levels of amino acids in the bloodstream largely remain constant, regardless of diet. Each amino acid plays a unique role in the body. When we don’t give our bodies the essential amino acids it requires, the body will begin to attack itself and break down muscle and other protein sources in order to maintain the concentration levels. This means that we need to consume high amounts of foods containing amino acids daily. If we have limited intake in any one of the essential amino acids, it affects how our bodies intake all the others, so in addition to having healthy levels, we also need a good balance.
Most adults require approximately 60 grams of protein each day. Complete proteins contain all of the essential amino acids. Complete protein sources include, meats, fish, eggs, soy and dairy products. Incomplete proteins contain some of the essential acids and include vegetables, beans and other plant products. A carefully balanced diet containing complete and a variety of incomplete proteins should supply the full complement of amino acids.
For those of us who don’t always eat a sensible, nutritious diet, here are supplement recommendations to ensure you are getting a balanced daily dose of amino acids:
B.A.M (Balance Amino Maintenance) Powder by Metabolic Maintenance – Balanced Amino Maintenance is a multiple amino acid formula containing free-form amino acids that can be readily absorbed and utilized by the body. B.A.M. is an excellent adjunct for the promotion of energy and neuro-cognitive function.
Free Form Amino Caps by Douglas Laboratories – Free form amino acids in a proprietary blend containing: L-Arginine, L-Ornithine, L-Glutamic Acid, L-Aspartic Acid, L-Lysine, Glycine, L-Leucine, L-Valine, L-Threonine, L-Methionine, L-Alanine, L-Serine, L-Tyrosine, L-Cystine, L-Isoleucine, L-Proline, L-Histidine, and L-Phenylalanine. 600 mg
Free Amino by Priority One – Free form amino acids for rapid assimilation into the body. Contains all 21 essential and nonessential amino acids in one vegetarian capsule. 600 mg
Amino Blend by Progressive Labs – A blend of 21 free form amino acids necessary for the growth and maintenance of all intra- and extra-cellular tissues.
Amino Sport by Biotics Research – A broad spectrum amino acid formulation that is useful for bodybuilding and as specific support for rehabilitation protocols.