Joseph R. Anticaglia MD
Medical Advisory Board
“Why do we need proteins?” We need proteins to survive and thrive. They’re a vital part of every cell and are present in every living organism. Unlike fats, the body cannot store proteins for future use. This means we need this indispensible nutrient in our diet every day.
When you eat an egg or chicken, the protein is broken down (denatured) into amino acids by the digestive juices of the stomach and G.I. tract. Just as the alphabet with 26 letters can form thousands of words, the 20 amino acids can form thousands of proteins.
Proteins are made up of these amino acids (building blocks of proteins), which are strung together looking like different beads of a necklace that can twist and fold into various shapes and sizes. Each bead represents an amino acid with a particular function.
At the direction of genes, amino acids in various combinations will be instructed to carry out specific tasks. Some will become antibodies that fight infections and diseases. Others develop into bones and muscles. Some come to be hormones, such as estrogen and testosterone, while others emerge as red blood cells. Others replace old or misshaped cells. The responsibilities and functions of proteins are countless. One can think of them as electricians or plumbers among many workers at a construction site, each with a specific job to do
There are various ways of classifying proteins. We must get some amino acids from food (essential), while the human body can make others on its own (non-essential).
Complete proteins are the protein foods that contain all nine essential amino acids needed to build new proteins (see below). We need to incorporate these protein sources into our diet on a daily basis, since the body cannot make them. They are usually of animal origin, such as; eggs, milk, cheese, beef chicken, pork and fish.
Incomplete proteins are food sources, generally from plants, that lack one or more of the essential amino acids or they might be in inadequate amounts (see below, non-essential). These foods include beans bread, nuts, rice and vegetables. One can overcome this problem by combining inadequate proteins. There are exceptions to the rule; e.g. soy bean and quinoa are complete proteins from plant foods.
Strict vegans eliminate all sources of animal protein and are susceptible to protein deficiencies. However, many are well aware of how to combine proteins to compensate for inadequate proteins in their diet. They combine rice and beans, incorporate soy beans and quinoa in their diet, have peanut butter on whole grain bread and use almond milk in cereal.
Protein Deficiency
Western countries usually associate protein deficiency with starvation in other parts of the world. However, insufficient calorie intake is not unheard of in the U.S. Weight loss diets, people with chronic illnesses, cachexia and anorexia nervosa can experience calorie and protein deficiency (marasmus). Those suffering from anorexia have complaints and physical signs linked to starvation
Proteins are essential to our well-being and should be a vital part of our diet. They’re found in all kinds of cells, from the hair on your head to the muscles in your toes. We need them to grow, repair and replace tissue for us to function well. They should be highlighted on our food shopping list. Greater understanding and more attention is now being paid to this crucial macronutrient.
Glossary
“9” Essential (Indispensible) Amino Acids
- Leucine
- Methionine
- Isoleucine
- Phenylalanine
- Hiistidine
- Lysine
- Threonine
- Valine
- Tryptophan
We get these essential amino acids by way of our diet. The body cannot manufacture the above amino acids…
“11” Non-Essential Amino Acids
- Alanine
- Glutamic Acid
- Arginine
- Glutamine
- Asparagine
- Glycine
- Serine
- Aspartic Acid
- Tyrosine
- Cysteine
- Proline
The body can manufacture (synthesize) these non-essential amino acids.
References
NIH, NCBI; Proteins and Amino Acids; National Academy of Sciences, 1989
NIH; Emily Wax, RD. Protein in Diet; 1/15/16
Hall, John E, PhD; Guyton and Hall; Medical Physiology; 2016
This article is intended solely as a learning experience. Please consult your physician for diagnostic and treatment options.