What are essential amino acids?

Protein usually gets discussed in grams, but what the body actually uses are the amino acids inside it.

Which amino acids are essential?

Twenty amino acids are used to build the body's proteins. Nine of them the body cannot make: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.

All nine have to come from food.

What claim wording exists?

The annex to Thai Ministry of Public Health Notification No. 447 (B.E. 2566) sets out statements for protein: protein contributes to a source of essential amino acids for body protein synthesis, and protein contributes to growth and helps repair body tissue.

Those statements belong to protein as a nutrient, not to any single amino acid on its own.

How do protein sources differ?

In the proportions of amino acids, not in whether they are present.

Animal proteins — meat, fish, eggs, milk — usually carry a complete proportion of the essential amino acids in a single source. The exception is collagen and gelatin, which contain no tryptophan.

Plant proteins vary. Grains tend to be relatively low in lysine; dried beans tend to be relatively low in methionine.

What does "rice with beans" mean?

It means combining sources whose weak points are different. Rice with beans, rice with tofu, or bread with peanuts gives a more complete amino acid profile than either alone.

They do not have to be in the same meal. Having a variety of sources across a day is enough.

Do single amino acids need supplementing?

For anyone getting varied, adequate protein, the essential amino acids arrive with the protein in food.

Where the diet is very restricted, planning several protein sources into meals is a more direct approach than supplementing one amino acid.

How do you read the label?

Labels usually give the salt form, such as L-lysine monohydrochloride. The figure after it is the weight of the compound, not of free amino acid.

If you take prescription medication, speak to a doctor or pharmacist before supplementing.

Dietary supplements are not intended to prevent, treat or cure any disease.