Amino acids are the building blocks of protein. Proteins and the amino acids they are made from are necessary to make or repair protein tissues, which include muscles, bones, cartilage, skin, and blood. There are 20 amino acids, including nine essential amino acids that your body cannot produce itself.
Your body digests or breaks up protein into amino acids when you eat protein-rich foods, like beans, tofu, dairy products, eggs, seafood, or whole grains. Your body absorbs amino acids from your digestive tract into your bloodstream.
Plant and animal proteins are made up of about 20 common amino acids. Amino acids are "essential," which means you must consume them from foods. These are also referred to as "indispensable amino acids." Your body cannot survive without them.
Essential amino acids include:
- Histidine: Helps make histamine, which is a neurotransmitter that aids in immune function, digestion, and sleep
- Isoleucine: Aids in the production of hemoglobin (an essential part of red blood cells that carries oxygen throughout your body)
- Leucine: Helps the body make proteins that aid in muscle growth and repair and regulates blood glucose (sugar) levels
- Lysine: Assists your body in the absorption of calcium and formation of collagen, both of which are important for muscle and bone health
- Methionine: Can be converted into molecules that contain sulfur that protect your tissues, repair DNA, and support cell function
- Phenylalanine: Is the precursor for dopamine and norepinephrine, which have antidepressant effects
- Threonine: Breaks down fat build-up in your liver and can reduce indigestion and gut problems
- Tryptophan: Helps your body make melatonin (regulates the sleep-wake cycle) and serotonin (regulates appetite, mood, pain, and sleep)
- Valine: Promotes muscle growth and repair and is thee precursor for the synthesis of penicillin
Nonessential
Youdo not need to consume nonessential amino acids, also known as "dispensable," from food. Your body can make these amino acids using only the nine essential amino acids.
Nonessential amino acids include:
- Alanine
- Arginine
- Asparagine
- Aspartic acid
- Cysteine
- Glutamic acid
- Glutamine
- Glycine
- Proline
- Serine
- Tyrosine
Conditionally Essential
Certain amino acids are conditionally essential. It depends on your overall health. Certain disease states can cause an amino acid to become conditionally essential.
A healthy adult may be able to make the nonessential amino acid tyrosine from phenylalanine, which is an essential amino acid. A young child may not have developed the enzyme needed to do this, which would make tyrosine an essential amino acid for them.
There are seven nonessential amino acids that sometimes become conditionally essential, such as:
- Arginine
- Cysteine
- Glutamine
- Glycine
- Proline
- Serine
- Tyrosine
Amino Acid Structure
Amino acids contain the elements carbon, hydrogen, oxygen, and nitrogen. A carbon atom is located at the center of an amino acid.
The carbon atom forms a bond with a hydrogen atom, an amino group, a carboxylic acid group, and an R group. An R group is a unique side chain that differentiates between each amino acid. Amino acids can connect to form a protein, which creates a 3D shape.
Amino acids are the building blocks of proteins, which are essential for muscle, bone, and skin health. Each amino acid has different benefits, but they generally perform functions like:
- Aid in the synthesis of hormones and neurotransmitters
- Break down food
- Grow and repair muscles
- Help support digestive and immune function
- Provide energy
- Strengthen skin, hair, and nail health
How To Get Enough Amino Acids
It's best to consume a variety of foods, which will supply a wide array of amino acids. You can also take amino acids in supplement form. It's important to talk to a healthcare provider before starting a new supplement.
You do not need to consume animal-based foods to meet all of your amino acid needs, including the nine essential amino acids. A varied diet also helps you take in a broad range of other nutrients, like vitamins, minerals, and fiber.
You do not need to worry about a strategy called food combining if you eat a plant-based diet. Food combining means pairing a plant food that's low in one amino acid with another that's high, like eating beans and rice together. You can obtain all of the amino acids in adequate amounts, even on a fully plant-based diet, if you eat a wide variety of foods overall.
Amino acids come from food, including plant-based and animal-based foods. Some foods provide more total protein—and therefore, more amino acids—than others per serving.
You can find amino acids in foods like:
- Beans, lentils, and peas
- Dairy products
- Eggs
- Fruits
- Nuts and seeds
- Seafood, poultry, and meat
- Soy products, like tofu and tempeh
- Vegetables
- Whole grains
It's a common belief that most plant foods are missing certain amino acids. The truth is that all plant foods contain all 20 amino acids. The amounts of some amino acids are simply low in certain sources, not absent.
A Quick Review
Amino acids are the structures that makeup proteins. Nine essential amino acids need to be consumed from food to build and repair protein tissues in your body.
The best way to meet your amino acid needs is to eat enough calories for your body and consume a balanced diet that provides enough protein. Talk with a healthcare provider if you have questions about how to meet your protein or amino acid needs.
