Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily
Protein is composed of two types of amino acids: essential and non-essential. The term “non-essential” is misleading, though, as Professor Anding explains. She also provides common examples of amino acids.
Our body uses approximately 20 basic amino acids, or protein building blocks, following the instructions from our genes, which assemble all the necessary proteins. While some genetic codes require short chains of amino acids—maybe as few as six or eight—others require multiple long chains that are intertwined. It becomes a complex three-dimensional structure that could be as intricate as a tangled ball of twine.
When you digest that protein, the hydrochloric acid in your gut or your stomach untangles that ball of twine; this process is called “denaturing” the protein, which changes the protein structure.
For example, you can see denatured protein every time you have eggs for breakfast. A raw egg has a clear albumen structure that is egg white. When you put that egg in a pan and provide heat, you are denaturing that protein, and you can actually see the process happen before your eyes.
The protein goes from a clear, viscous solution to something that is white and solid. You are denaturing that protein structure.
You are untangling that ball of twine, and you end up with a different product. Another example of denaturing protein is if you’ve ever had a permanent to make your hair curly, you are denaturing that protein structure in your hair and making it do something else.
Essential and Non-Essential Amino Acids
The amino acid compound includes essential amino acids, which are specific amino acids that you must have in your diet because your body doesn’t produce them on its own. The essential amino acids include histidine, leucine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Lysine can help treat cold sores, reduce anxiety, and improve calcium absorption. Leucine, which is found in meat, can be used to stimulate muscle growth and prevent age-related muscle deterioration.
Non-essential amino acids are important for creating protein. They’re just as vital as the essential ones, so you may be wondering why they’re called “non-essential.”
Non-essential means that under normal circumstances of wellness, you can make those amino acids in your body. The non-essential amino acids are alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, proline, serine, and tyrosine.
Some muscle-building products contain arginine as well as pharmaceuticals used to treat heart conditions, high blood pressure, and dementia. Glutamine, which is also found in many supplements, plays a critical role in supporting the immune system, protecting your intestines from harmful bacteria or toxins, and improving muscle recovery after exercise.
It’s also critical to understand that these non-essential amino acids are being made by your body when you are well. There are conditions and circumstances in your life when your body can’t keep up with this demand.
Sometimes, depending on the source that you read, you’ll see some of these amino acids shuffled between essential and non-essential. Part of that is because during periods of stress and illness, your body may actually need some dietary support of these traditionally non-essential amino acids.
The other reason to understand why these are important is that there are diseases involving protein metabolism. NutraSweet®, which is also marketed under the name “Equal®,” is composed of the two amino acids aspartic acid and phenylalanine that together are sweet but apart are not.
Have you ever opened a can of diet soda and thought, “This tastes like carbonated water?” That soda was probably stored in a warehouse, and the presence of heat split the amino acid structure apart, meaning it is no longer sweet.
You can also do a little experiment at home. If you ever have hot cocoa that is sweetened with NutraSweet or Equal and you let it sit in a glass for a prolonged period of time, what ends up happening is that it starts out pretty sweet; then over a period of time, as those two amino acids are separating, it becomes less sweet.
This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.
Professor Roberta H. Anding is a registered dietitian and Director of Sports Nutrition and a clinical dietitian at Baylor College of Medicine and Texas Children’s Hospital. She also teaches and lectures in the Baylor College of Medicine’s Department of Pediatrics, Section of Adolescent Medicine and Sports Medicine, and in the Department of Kinesiology at Rice University.