For a while it was thought that there were only 20 amino acids, and many websites still reflect this today, but in fact, a couple of new aminos were discovered making a total of 22 amino acids. But how many amino acids are there really?
The real question is how many amino acids exist beyond the 22 we know of so far, and what about other types of amino acids? The reality is that amino acids, which are the basic building blocks of the body, are in abundance within the body. They are sources of energy such as carbohydrates and fats, except that amino acids contain nitrogen (N); because of this they play a role in forming muscles, tissues, organs, skin, and even hair.
There are 20 amino acids in the our standard genetic code, and the additional 2 aminos are outside this realm. These are comprised of the amino acids selenocysteine and pyrrolysine. These amino acids were discovered only about three decades and two decades ago respectively.
Nine essential amino acids act as the precursors to neurotransmitters in the brain and enzymes that help with bodily functions like digestion. These amino acids are essential for health, and regulate the body’s metabolic processes. Plus they transport oxygen and nutrients in the body.
How Many Kinds of Amino Acids are there?
Different amino acids have different functions. How many amino acids, types, or kinds that exist depend on whether they are:
Essential – 9
Non-essential – 13
How Many Essential Amino Acids Are There?
How many amino acids are “essential” (meaning you must get them from food)? They are listed as: histidine, leucine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine.
Several essential amino acids are available in supplement mixes as BCAAs, or branch chain amino acids. The specific aminos included are often leucine, isoleucine, and valine.
How Many Amino Acids are Non-Essential
How many amino acids are “non-essential” (meaning your body makes them)? These are listed as: arginine, alanine, asparagine, aspartate (aspartic acid), cysteine, glutamate (glutamic acid), glutamine, glycine, proline, serine, tyrosine (interchangeable with phenylalanine), selenocysteine, and pyrrolysine. Although pyrrolysine is not used by humans.
Semi-Essential Amino Acids
However, how many amino acids from one of the above groups are actually conditional or “semi-essential” amino acids? These are: arginine, cysteine, glycine, glutamine, proline, serine, tyrosine.
There are 22 Amino Acids
These above are the 20 more well-known amino acids; however, just how many amino acids exist actually are counted as being over 200 in numbers, but the 22 proteinogenic amino acids are the ones that are commonly known.
These more commonly known aminos can be found in food (all meat such as beef, pork, chicken, seafood, and even eggs are excellent sources of all 22 amino acids). They can also be bought as amino acid supplements individually or as a complex of many in balanced forms for their health benefits.
But haven’t we missed some? What about ornithine and citrulline? Just as phenylalanine and tyrosine are interchangeable, so are ornithine, citrulline, and arginine. Although they have different chemical structures, they have similar benefits and effects on the body and can be interchanged in the diet. For example, both arginine and citrulline act to increase nitric oxide in the body.
How many amino acids have you had in your diet today?
Recommended Daily Intakes for Essential Aminos
Here are the recommended daily intakes in milligrams per kilogram of body weight. Here is an in depth guide from the WHO on the calculations behind the recommended daily intakes.
- Valine: 26mg per kg
- Tyrptophan: 4mg per kg
- Threonine: 15mg per kg
- Phenylalanine and Tyrosine: 25mg per kg
- Methionine and Cysteine: 15mg per kg
- Lysine: 30mg per kg
- Leucine: 39mg per kg
- Isoleucine: 29mg per kg
- Histidine: 10mg per kg