List of Essential Amino Acids

Marye Audet
Reviewed by Terri Forehand RN
Amino acids are needed to make protein

The human body uses a number of essential amino acids to manufacture protein. While the body can manufacture a number of the necessary amino acids on its own, there are some that the body does not have the ability to make. The term "essential" is used for the ones that the body cannot manufacture. People must obtain these substances through their diets or supplements.

Essential Amino Acids

Because the human body cannot manufacture essential amino acids, people must get them from their daily diet and/or supplements. specifies the needs of children and adults as follows.

Eight Essential Amino Acids for Everyone

These are eight essential amino acids that everyone needs:

  • Isoleucine
  • Leucine
  • Lysine
  • Methionine
  • Phenylalanine
  • Threonine
  • Tryptophan
  • Valine

Two More Needed by Children

In addition to the list above, infants and children also need the following essential amino acids:

  • Arginine
  • Histidine

World Health Organization Guidelines

The World Health Organization, WHO, has developed a guideline for the amount of essential aminos that you should get on a daily basis based on your body weight. The table that follows gives these guidelines for kilograms and pounds.

Essential Amino Acids
Amino Acid Mg per Kilogram of Body Weight Mg per 140 lbs of Body Weight Associated With
Isoleucine 20 1400
Leucine 39 2730
Lysine 30 2100
Methionine 15 1050 Cysteine
Phenylalanine 25 1750 Tyrosine
Threonine 15 1050
Tryptophan 4 280
Valine 26 1820

Understanding Essential Amino Acids

Amino acids are important to the body because they are the building blocks of protein, necessary for the growth and repair of cells. They work together in balance. If there isn't enough of just one, all of the rest will be less effective.

Amino acids are important to the proper function of these systems:

  • Cell growth and repair
  • Metabolism
  • Central nervous system

See Protein and Amino Acid Requirements in Human Nutrition, a technical report publication of the World Health Organization, to learn more.

Making the Best Food Choices

If you're interested in making sure that you get enough amino acids in your diet, it's important to know what foods are high in protein. Your body needs protein-rich foods to stay healthy, and foods need to contain all eight essential aminos for your body to assimilate them effectively. The protein in foods that are unbalanced in amino acids tend to be turned into fat and carbohydrates. It's simple: in order for your body to convert amino acids into protein, you need to consume high-quality protein from high-quality sources.

Amino Acids from Animal Sources

Nearly everything you eat contains amino acids. Foods that come from animal sources are the best suppliers of all of the aminos:

  • Chicken
  • Beef
  • Eggs
  • Milk
  • Fish
  • Pork
  • Cheese
  • Yogurt
  • Game

Amino Acids from Plant Sources

Plant sources tend to lack at least one of the amino acids, so vegetarians often need to combine two incomplete proteins to get a complete protein that includes all of them. Plant combinations are as follows:

  • Legumes with seeds or nuts
  • Legumes with whole grains
  • Seeds or nuts with whole grains

A few plants offer the complete spectrum of amino acids:

  • Buckwheat
  • Quinoa
  • Hemp seed
  • Amaranth

Should You Take a Supplement?

Under normal circumstances, it is not difficult to get all of the essential amino acids necessary from your diet alone. It is always important to eat a well-balanced, varied diet with lots of fruit, vegetables, and whole grains. In most instances, you won't need supplements since the best way to get these nutrients is through your diet. If, however, there is a reason that you are not able to do so, then supplements may be the way for you to go. It is always important to discuss your plans to supplement your diet with your health care provider.

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List of Essential Amino Acids