Amino acids (AAs) are vital molecules often referred to as the building blocks of life. The body cannot function properly without the 20 different types of amino acids it requires. These 20 amino acids are further broken down into three groups: essential, nonessential, and conditional.
The body’s cells cannot manufacture the nine essential amino acids necessary to support adequate functions. They must come from outside sources, primarily the food we consume. These 9 amino acids are found in high concentrations in protein-rich foods, including fish, poultry, eggs, dairy, and meat. Soy, quinoa, and buckwheat contain all nine essential amino acids, making them the only plant-based “complete” protein sources.
What are amino acids?
Amino acid compounds are organic chemicals consisting of carbon-hydrogen bonds with a side chain (R groups) that determines the molecule’s function in the body. They are primarily composed of carbon, hydrogen, nitrogen, and oxygen. These protein building blocks feature long amino acid chains (polypeptides), and with thousands of proteins in the body, each has a unique amino acid sequence. Amino acids provide the body with a source of energy.
Amino acids result from the breakdown and digestion of proteins. In return, the body uses the amino acids to further break down food, conduct tissue repair, regulate immune functions, build muscle, and carry out other critical functions.
The proteins formed by AA chains linked to peptides are unique in their properties based on the number and arrangement of the 20 amino acids in the chain. More than 100,000 unique proteins are in human bodies, formed with the help of approximately 20,000 unique protein-encoding genes.
Different Groups of Amino Acids
The body has three different groups of amino acids, which also differ due to their R groups, which affect their structure, polarity, and electrical charge. The side chains for the twenty amino acids are shown in the lists of essential and nonessential AAs below:
- Essential amino acids
The body cannot produce these nine amino acids. They are sourced from food, primarily protein, and include the following:
- Histidine: electrically charged side chain – basic
- Isoleucine: hydrophobic side chain – aliphatic
- Leucine: hydrophobic side chain – aliphatic
- Lysine: electrically charged side chain – basic
- Methionine: hydrophobic side chain – aliphatic
- Phenylalanine: hydrophobic side chain – aromatic
- Threonine: polar neutral side chain
- Tryptophan: hydrophobic side chain – aromatic
- Valine: hydrophobic side chain – aliphatic
- Nonessential amino acids
The body can produce these 11 nonessential amino acids, which are also found in food:
- Alanine: hydrophobic side chain – aliphatic
- Arginine: electrically charged side chain – basic
- Asparagine: polar neutral side chain
- Aspartic acid: electrically charged side chain – acidic
- Cysteine: polar neutral side chain
- Glutamic acid: electrically charged side chain – acidic
- Glutamine: polar neutral side chain
- Glycine: unique amino acid
- Proline: unique amino acid
- Serine: polar neutral side chain
- Tyrosine: hydrophobic side chain – aromatic
- Conditional amino acids
Although conditional amino acids begin as nonessential ones, they can convert to essential AAs when necessary, such as when health or illness issues occur. In some cases, such as when recovering from a serious injury or medical condition such as fighting cancer, the body cannot produce enough of the AA it needs, as with arginine. Supplementation may be beneficial at these times. Arginine and glycine are also vital during pregnancy and are conditionally essential during that time.
Conditional amino acids include the following (R groups not mentioned here as they are shown above):
While the body produces adequate nonessential amino acids, we must get the nine essential ones from food sources. Some people, especially athletes and bodybuilders, use amino acid supplements to boost their AA levels. However, because supplements are not regulated, there is no way of knowing whether what is on their labels is correct, not to mention the legitimacy of the amount of stated compounds and the safety of the levels.
One example of amino acid supplements is growth factor-9, which is stated to increase HGH levels. Find out if this is true by checking GF-9 reviews and learning if this product is beneficial.
In some instances, taking high or chronic doses of specific amino acids has been shown to cause significant health concerns, such as patients with myocardial infarction taking chronic arginine supplementation. Glutamine may also cause problems for some individuals. Only an experienced clinician should determine if amino acid supplementation is recommended.
Health Benefits of Amino Acids
Amino acids ensure the body can perform adequately, with AAs converting into crucial neurotransmitters, structural proteins, and more that help regulate vital functions.
Your amino acid requirements may vary depending on your stage of life, health status, and physiological needs.
Some of the leading functions that essential amino acids support include the following:
- Increasing energy levels
Some amino acids, such as valine, lysine, and isoleucine, are excellent energy sources for the body. Isoleucine supports hemoglobin production to help your blood supply oxygen to your tissues.
- Digestion regulation
The amino acid histidine promotes the production of the neurotransmitter histamine, which supports digestion.
- Supporting the musculoskeletal system
Numerous amino acids play a role in supporting the musculoskeletal system. Bone growth requires lysine for calcium absorption. Muscle function support comes from isoleucine and valine, while muscle repair benefits from leucine. Glycine, a nonessential amino acid, also helps promote creatine production for strong muscles. The nonessential AA asparagine helps with muscle tissue creation.
- Immune system support
The body uses lysine, threonine, and histidine to boost immune system functions to attack viruses. Isoleucine also helps with immune functions, as does the nonessential amino acid glutamine.
- Improving sleep patterns
The amino acids tryptophan and histidine help maintain and balance natural circadian rhythms to improve sleep, especially when higher cortisol levels due to stress get in the way. Serine is a nonessential AA that helps with sleep and supports the central nervous system and brain.
- Mood balance and support
The same amino acid that helps us sleep after having a Thanksgiving turkey dinner, tryptophan, plays a leading role in serotonin production, the feel-good hormone. Tyrosine is a nonessential amino acid that assists with adrenaline, thyroid hormones, and dopamine production.
- Promoting healthy skin, hair, and nails
Elastin and collagen are the building blocks of skin, hair, and nails, and their production also relies on proteins such as growth hormone. Collagen production gets a boost from the amino acids lysine and threonine, the latter of which also helps promote elastin. The nonessential AAs, proline and cysteine, help with collagen production and cellular function, while glycine supports vibrant skin and collagen production.
- Hormone production
Amino acid hormones, such as growth hormone, rely on various AAs for their production. Leucine promotes growth hormone production and helps maintain proper blood sugar levels. Lysine helps to promote healthy hormone levels. Aspartic acid is a nonessential AA that helps with hormone production.
- Neurotransmitter production
Neurotransmitters communicate throughout the nervous system, relaying vital messages that regulate critical functions. Phenylalanine helps with neurotransmitter production, including dopamine, epinephrine, and norepinephrine. Glutamic acid, a nonessential AA, is synthesized into glutamate to support communication between the brain’s nerve cells.
- Weight management
The amino acid threonine helps metabolize fat, while methionine regulates the metabolic rate, supports essential mineral absorption, and helps the body with detoxification. Proline is a nonessential AA that assists with regulating metabolism.
The nonessential amino acid alanine plays a role in healthy liver functions, while arginine helps dilate blood vessels through nitric acid release to improve circulation and benefit heart health.
As the building blocks of protein, the 20 amino acids keep the body running at peak performance. To ensure you get enough of the 9 essential AAs your body does not produce, ensure you eat a well-balanced diet getting plenty of protein. While not complete proteins, beans and nuts provide the body with some of the extra protein you need. Increase your protein intake if you are not confident you get enough essential amino acids from your diet.
Speak with your doctor before taking amino acid supplements, especially since they are not FDA-approved. The right supplements, taken as needed, may help balance your body. If you suspect a hormone imbalance, contact an endocrinologist/hormone specialist for help.