Essential Amino Acid: Definition & Overview

Instructor: Danielle Haak

Danielle has a PhD in Natural Resource Sciences and a MSc in Biological Sciences

What are amino acids, and what makes some of them essential while others are nonessential? Learn more about what amino acids do for your body and how you can make sure you are getting the full range you need to stay healthy.

Aren't All Amino Acids Essential?

An amino acid is an organic compound used to create proteins in the body. Amino acids are the building blocks of proteins, and proteins are the building blocks of life. When your body digests proteins, it breaks them down into amino acids, which are then used to make more proteins. It may sound confusing, but let's look at the difference among the three types of amino acids. We have nonessential amino acids that can be made by the body, even if we don't consume food that help us make them. Conditional amino acids are usually only essential during times of stress and illness. Essential amino acids are not made by the body, so we HAVE to get them through our food. There are nine essential amino acids required for adults, and they are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Children have an extra essential amino acid called arginine, but once a person reaches adulthood, this amino acid is no longer essential.

What Foods Have Essential Amino Acids?

Because essential amino acids can't be made by the body, it needs a little outside help - we have to eat these amino acids in our foods and let our body do the rest of the work. Luckily, some foods are packed with proteins and thus, essential amino acids. In fact, meat, dairy, eggs, poultry, and seafood will each provide ALL nine essential amino acids. However, because some of these foods can also be high in fat, it's best to opt for lean options so you don't overdo it. If you do not eat any animal products (called veganism), you can combine different types of plant-based foods to meet your amino acid needs. Beans, brown rice, tofu, lentils, and nuts each have SOME of the essential amino acids but are not as complete as the animal-based foods. So, you should eat several types of plant foods every day, and this will help you get all those nutrients you need to stay healthy. To give you a ballpark figure, approximately 10-35% of your daily food intake should be proteins. If you are concerned you aren't getting all of the essential amino acids you need, you can always work with a nutritionist to identify the best combinations of foods you like that will meet your needs.

Examples of foods that contain each type of essential amino acid (plus a few extras)

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