Food Sources of the Nine Essential Amino Acids

by Melissa Chichester

Amino acids perform many functions related to cellular metabolism, but they are best known as building blocks of protein.

Amino acids are necessary for growth and development since protein helps maintain all critical structures in the body. In short, we need amino acids to live and thrive!

Amino acids are distinguished from each other by structure, function, and the body’s ability to produce them. And nine essential amino acids cannot be made by the body; therefore, they need to be consumed through food or nutritional supplements. 

Today, we’re sharing how you can consume these amino acids in foods and why they are so important.

The nine essential amino acids are tryptophan, valine, leucine, isoleucine, lysine, phenylalanine, methionine, threonine, and histidine. 

And we’ll start with one food that contains them all: eggs! Eggs are considered a complete protein source. If you consume eggs regularly, great! But you don’t, there are many other foods that are rich in amino acids or contain them in some amounts. Most of these foods are meat and dairy products.


Tryptophan is usually associated with feeling sleepy after eating turkey, because, in the body, it helps produce calming hormones serotonin and melatonin. In supplement form, tryptophan is better known as 5-HTP, which helps support and relaxed mood, as well as feelings of well-being.* Tryptophan is also found in chocolate, poultry, dairy products, and oats. 

Valine, leucine, and isoleucine

Valine, leucine, and isoleucine are better known as BCAAs, or branched-chain amino acids. BCAAs make up a large part of the amino acid composition in muscle tissue and are commonly used by athletes and bodybuilders to support muscles.* Whey, milk, chickpeas, lentils, brown rice, lima beans, and almonds are all sources of BCAAs. 


In the body, lysine helps produce collagen, and as a supplement, it supports healthy skin.* When taking at least 800mg, it may help the body absorb calcium.* High-protein foods, including meat and beans, are good sources of lysine. Other sources of lysine include spirulina, cod, cheese, and pork. 


Phenylalanine is an essential amino acid that can be converted into the non-essential amino acid tyrosine. Foods that contain phenylalanine include cheese, beef, lamb, chicken, beans, pork, and whole grains. 


Methionine supports the production of glutathione, and it can be converted into SAM-e (S-Adenosyl Methionine). SAM-e is known to support emotional well-being.* You are probably noticing a trend with these amino acids, but good sources of methionine include beef, lamb, cheese, pork, nuts, and dairy products. Soy and beans also contain methionine, but animal sources contain more bioavailable amounts of methionine


In the body, threonine is converted to glycine, which is an amino acid found in muscle tissue, connective tissue, and skin.  

Glycine can help to reduce morning fatigue after experiencing sub-optimal sleep*

Lean beef, lentils, pork, liver, and cheese are all sources of threonine. Shellfish also contain threonine. 


Histidine is involved in many metabolic processes, including the production of histamine. It used to be thought that histidine was only essential for infants; however, researchers have since discovered that it is also essential for adults. Food sources of histidine include whole grains, pork, chicken, tuna, navy beans, tofu, and pumpkin seeds.