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Amino acids -  main structural chemical formulas


I honestly don’t get this whole AMINO ACID thing. What are all the essential and nonessential AMINO ACIDS, and do we need them if they are nonessential and why are the ‘essential’ so, well, essential? – Bryven


When we digest protein, we break it down into its individual amino acids for absorption. Amino acids are the building blocks for all our bodies’ protein. Since humans can’t store protein, we are constantly modifying and rearranging amino acids into peptide chains of varying combinations and lengths to make up the different proteins we need, whether functional (e.g. hormones and enzymes) or structural (cells).

There are 20 amino acids we can use to build protein – see title image. In a process called turnover, our metabolism can create many of the amino acids from leftover pieces after used proteins are broken down. Those we synthesize are called non-essential. Those that we can’t make are called essential because they must be obtained from our food. All 20 amino acids are needed, though! They are vital to our survival since our body proteins are made up of combinations of all the amino acids.


9 Essential amino acids (dietary only): Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, and Valine.


11 Non-essential amino acids (we can make): Alanine, Arginine*, Asparagine, Aspartic Acid, Cysteine*, Glutamine, Glutamic Acid, Glycine, Ornithine, Proline, Serine, Tyrosine*.


What happens if you don’t get adequate essential amino acids from food? Well, since your body can’t make them and there’s no storage, it will need to break down intact proteins in a process called catabolism. Just as would happen if you were severely energy deprived, the body would degrade the proteins in use. This can lead to muscle loss!
So eat a diet adequate in quality protein that contains many of the essential amino acids. The food items with the most complete combination of amino acids are meat, eggs, fish, poultry and milk products. These animal sources offer all the required amino acids. Vegetable sources that come close are beans and legumes, but an adequate plants-only diet is easily achieved with balance and planning. Read more about vegan diets here: Is Protein an Issue for Vegans?


* Arginine, Cyteine and Tyrosine are essential for infants and growing children.


 – Debbie J., MS, RD

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Debbie James is a registered dietitian. Any views or opinions presented in this article are solely those of the author and do not necessarily represent the opinions or recommendations of Fitness International, LLC.



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