The Bricks & Mortar of Protein
Amino acids are crucial to overall well-being.
By Lisa James
Protein is the stuff our bodies are made of. Muscle, connective tissue, skin, hair, internal organs: Each represents a different way in which these intricately folded molecules are linked together to give the body its shape.
In turn proteins are made up of amino acids, which supply the nitrogen on the body’s shopping list of vital substances. So it’s no surprise to learn that amino acids play a crucial role in building tissue, including the abundant tissue found in our muscles.
But proteins are more than just the body’s scaffolding. Some enable the transmission of nerve impulses, others help transport fats through the bloodstream, while still others are used to make enzymes, substances that serve as the body’s construction engineers. And those are just a few among thousands of possible examples.
Creating all these proteins requires the optimal mix of amino acids. And what’s remarkable is that, of the millions of different amino acids in the universe, nature uses only 20 basic types of these building blocks to manufacture every protein found in the body.
The body creates proteins by following the directions in its genetic code, or DNA. “Proteins each have their own amino acid sequence, or pattern,” says Keri Marshall, ND, who practices in Bethesda, Maryland, and is the author of User’s Guide to Protein and Amino Acids (Basic Health). “The amino acid sequence gives a protein its unique functioning capability, making one protein greatly different from the next.” Some, such as the collagen that makes up much of the body’s substance, are structural proteins. Others, such as the lipoproteins that carry blood fats, are functional proteins.
Different amino acids have different properties. Some are acidic while others are basic, some attract water while others repel it and some attract different elements, such as sulfur, found in the body. This explains how a relatively small pool of amino acids—which includes some additional modified versions—can be used to make thousands of proteins.
Amino acids are also classified according to whether they can be created by the body or not. Those that can be are nonessential amino acids. Others are essential because the body needs to obtain them from dietary sources.
Some nonessential amino acids may become conditionally essential in certain cases. Genetic quirks can make it more difficult for some peoples’ bodies to form normally nonessential aminos. Metabolic dysfunction resulting from infections and injuries (including burns and surgery) can also cause amino acids to become conditionally essential.
Dietary proteins that contain sufficient amounts of all the amino acids are said to be complete. Foods of animal origin contain complete proteins.
Proteins from plant-based foods tend to be incomplete; that is, they don’t contain the entire range of essential amino acids. (Soybeans are a notable exception.) That’s why vegetarians are generally advised to eat a variety of whole grains and produce throughout the day to obtain a complete amino set.
Proteins are also graded in terms of how digestible they are. For example, leather is a complete protein. But because the body can’t digest leather, its protein is useless from a nutritional standpoint. Milk and eggs score high marks for digestibility.
High-quality protein shakes supply all amino acids in a readily digestible form; they often include an array of vitamins, minerals and other key nutrients. Some are based on whey, the liquid that remains after cheese is produced. Other shakes combine proteins taken from various plant sources, including sprouted brown rice, chia, flax, pea and soy.
Amino Acid Benefits
“People often do not realize their need for amino acids because they are not aware of how busy the human body is,” says Eric Braverman, MD, of PATH Medical in New York City (www.pathmed.com) and author of The Healing Nutrients Within (Basic Health). Bone marrow makes 2.5 million red blood cells each second, he notes, while every four days most of the gastrointestinal tract lining is replaced. “All this continuous repair work requires amino acids.”
The body’s ability to use amino acids can be compromised. “Poor digestion, infection, trauma, stress, drug use, age, environmental pollution, processed foods and personal habits such as smoking and drinking are factors that can influence the availability of essential amino acids,” says Braverman. He adds that nutritional deficits, especially of vitamins B6 and C, “can contribute to deficiencies of essential amino acids in the body.”
As a result, practitioners may suggest supplementation with one or more amino acids (always consult with a healthcare practitioner, especially if you have a pre-existing condition). Some of those more commonly recommended include:
Arginine—This conditionally essential amino acid is best known for its role in the production of nitric oxide, the substance that helps arteries relax (which makes arginine a nitric oxide precursor). Arginine is thus crucial for cardiovascular and sexual health, both of which depend on proper blood vessel function. It also plays key roles in wound repair, ridding the body of ammonia, a waste product, and promoting the release of hormones, including human growth hormone.
Branched Chain Amino Acids (BCAAs)—This grouping includes the essential amino acids isoleucine, leucine and valine. They help build and fuel muscles, especially during prolonged exercise.
Carnitine—Synthesized from the amino acids lysine and methionine, carnitine promotes energy release by moving fatty acids, a potent fuel source, into the cellular power plants known as mitochondria. No cells in the body work harder than those in the heart muscle, so it’s not surprising that carnitine is concentrated there. High concentrations of carnitine are also found in sperm cells, and it has shown promise in the treatment of male infertility. It is also serves as an antioxidant.
Cysteine—This conditionally essential amino acid is vital for proper hair growth and is used to make glutathione, a powerful antioxidant. NAC, the form of cysteine most commonly used in supplements, helps to counteract environmental toxins and to thin mucus, easing respiratory problems.
Glutamine—A conditionally essential amino acid, glutamine is crucial to digestive health. It is the preferred fuel source of the cells that line the small intestine and has shown an ability to ease heartburn and protect the stomach against ulceration. Glutamine is also used in men’s health formulations (often with the amino acids alanine and glycine).
Histidine—This essential amino acid has been used to help ease rheumatoid arthritis. But its most notable use has been in the support of healthy sexual functioning in both men and women; it is often used in male formulations with carnitine and the amino acid phenylalanine.
Lysine—An essential amino acid, lysine is best known for helping to fight herpesvirus infections, including cold sores and shingles. It also helps the body absorb calcium and may play a role in reducing anxiety.
Methionine—This sulfur-bearing essential amino acid, in the form SAMe, is used to help ease depression and chronic pain. The body also uses it to properly utilize fats and vitamins.
Serine—Conditionally essential, serine (including a supplemental form, PS) plays a crucial role in brain health by fostering the release of neurotransmitters, substances that allow nerve cells to communicate with each other. PS is used to help prevent memory and cognitive deficits associated with age.
Taurine—Not technically an amino acid, taurine is created from cysteine. It is a major component of bile, used by the body to help digest fat, and acts as an antioxidant. It has been shown to reduce the release of blood fat components linked to cardiovascular disease.
Tryptophan—This essential amino acid (available in supplemental form as 5-HTP) serves as a precursor to the neurotransmitter serotonin, which helps regulate mood. 5-HTP has been found to be helpful for both depression and insomnia.
Tyrosine—Conditionally essential, tyrosine is a precursor to thyroid hormone as well as several neurotransmitters. It has been used in the treatment of mild depression. Because of its link to the neurotransmitter dopamine, tyrosine is being researched as a possible therapy for Parkinson’s disease.
Protein is needed for both structure and function—and amino acids play a vital role in building protein.