On Nutrition

DEAR DR. BLONZ: I’m wondering about the differences between the protein found in red meat, such as steak, and that found in seafood, such as shrimp. I only eat red meat a few times a month, and am concerned about whether I’m getting enough protein. I take a multivitamin every day, but know that nutrients from food are more important. On the physical side, I do a cardio workout every other day, working with weights on the alternate days. I don’t smoke, drink minimally and am overall very healthy. My only concern is nutrient-based. How does the quality of the protein in shrimp compare with the protein from steak? -- L.W., Madison, Wisconsin

DEAR L.W.: Think of protein as what we are made of. The list of body proteins includes hair, skin, muscles, organs, blood cells, nerve tissue, brain tissue, hormones, antibodies, DNA, RNA, and even the enzymes used to digest the foods we eat. It’s fitting that the word “protein” comes from the Greek “proteios,” which means “primary” or “first.”

Proteins are made up of long chains of assorted amino acids. They tend to be too large to be absorbed intact, so after being eaten, our stomach releases acid to denature the protein and facilitate the action of the digestive enzymes in the small intestine. Enzymes separate proteins into their amino acid constituent parts, which can then get absorbed into the body. Once in the body, these amino acids serve as building blocks for the body to make any of the proteins it needs. The human body can actually make its own amino acids, but there are exceptions; the ones we can’t make are referred to as the essential amino acids, and they must be provided in the diet.

One of the ways that scientists “score” proteins is by looking at the types of amino acids they contain, and then comparing this with the amino acids in our body proteins. Those that compare most favorably have the highest scores. Egg whites (albumin) are usually considered to be the ideal protein, followed by dairy, fish, beef and poultry. Contrast this with lower-scoring vegetable proteins, such as corn, wheat and rice, where there can be plenty of amino acids, but lesser amounts of one or more of the essential ones. This lessens the overall score.

There are minor differences between the proteins that make up red meat and seafood, and these are mainly different amounts of the various essential amino acids. Both are considered high-quality, “complete” proteins, in that they both contain good amounts of all the amino acids the body needs to make its own protein. To answer your question, you should consider them to be comparable.

Most people have no problem getting the protein their body requires. The key is to have a mix of high-quality protein foods, together with other protein-containing foods, including grains, legumes, vegetables, nuts and seeds. Vegans accomplish this by sticking to plant foods to satisfy their requirements.

Be advised that in this country, we tend to eat more protein than our bodies need. Excess protein doesn’t give you more muscles; it becomes nothing more than calories that get turned into body fat. Let me close by saying that you have my admiration for your healthy exercise habits.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.

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