Part One: Protein Explained

With more and more emphasis on nutrition and how it impacts our health, there are many terms that we throw around regularly but don’t necessarily understand all that well.  Without being a registered dietician or biochemist, there are some basic facts about nutrients that can help us to understand what our bodies need, why we need them, and where to get them.

Basic Nutrition

From the foods we eat, we get energy in the form of calories.  Nutrients and other substances needed for growth and health are also derived from the foods that we eat.  Carbohydrates, proteins, and fats supply all of the calories, or energy units, our bodies need.  Vitamins and minerals are needed for converting carbohydrates, proteins, and fats into energy as well as the building and maintaining of muscles, blood, bones, and other body tissues.  Essential nutrients are required by our bodies but must be obtained from our diets because we cannot produce them on our own or at least not in sufficient amounts.

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What are Proteins

Proteins are complex molecules of varying sizes comprised of amino acids.  Our bodies use these amino acids for various functions.  Complete protein sources are those that contain adequate amounts of all of the essential amino acids.  Incomplete protein sources are those that supply a low amount of one or more essential amino acids.  In general animal protein sources, such as meat, poultry, eggs, and dairy are complete protein sources, while plant protein sources are generally considered more incomplete. 

So how then do vegetarians get all of their essential amino acids?  Those that eat a large variety of incomplete protein sources are able to get adequate amounts of the essential amino acids.  That’s because the amino acids provided in beans and legumes are different from those provided in nuts and seeds.  Eating a diet comprised of many sources of proteins provides for the full complement of essential amino acids. 

Determining which sources to obtain protein from depends on a variety of factors including current BMI, disease status, and dietary preference to name a few.  Individuals who are trying to lose weight and are watching calorie intake may choose to gain more protein from plant-based sources due to their overall lower caloric load as compared to animal-based sources.  Additionally, those that suffer from certain chronic illnesses, such as kidney disease, should work with a registered dietician and their nephrologist to determine the best sources of protein and how much to eat. 

What Proteins do in the Body

  • Provide the structural materials to build muscles, skin, bones, hair, and fingernails.
  • Assist in chemical reactions that occur in the body.
  • Make movement possible through muscle contraction and relaxation.
  • Transport substances in the blood from one area of your body to another.
  • Used to build antibodies to fight disease and infection
  • Help in the clotting process.
  • Regulates pH, or the acid/base balance in your blood and urine.
  • Maintains fluid balance.

Signs of Too Little Protein

Although most Americans get enough protein in their diets, it stands to reason that based on what protein does in the body you may show signs when not consuming enough.  These could include dry and flaky skin, ridging on the nails, and brittle or thinning hair.  Weakness and fatigue can occur.  Additionally, you could see mood changes and fluid buildup, particularly in the abdomen and extremities.  Finally, injuries could be slow to heal or illness could be occurring more frequently or linger for longer than usual.

Protein Recommendations for Older Adults

The U.S. Department of Agriculture and the U.S. Department of Health and Human Services publishes dietary guidelines every 5 years based on recent scientific reviews of the current evidence on health topics and nutrition for every stage of life.  Most recently the 2020-2025 guidelines state that men 60 and over should consume 5.5-6.5 ounce-equivalents of protein daily, while the recommendation for women age 60 and over is 5-6 ounce-equivalents of protein daily.  Below is a table of 1 ounce-equivalents to help you determine great sources of protein to include in your daily meal plan.

What to Remember

  • The best sources for any macro or micronutrients are always derived from whole foods and not supplementation.  Talk with your doctor before beginning any new supplements which could include – vitamins, shakes or powders, and items classified as medical foods.
  • Obtain your protein from a variety of sources to gain the largest complement of essential amino acids that your body needs for optimal function.
  • Consider your weekly protein intake rather than aiming for a daily goal, particularly if you like to have variety in your diet.  If you choose to have a Meatless Monday, think about having higher sources of protein on Tuesday so the overall balance for the week is maintained.
  • Recommendations for protein intake are based on studies of healthy individuals.  People who suffer from medical conditions, particularly kidney disease, should always discuss their target daily protein intake and best protein sources with a registered dietician and their medical provider.
  • Next Up:  Carbohydrates

Resources

Are You Getting too much Protein? | MayoClinicHealthSystem.org (2022, April 29).

Protein Foods | MyPlate.gov (2020).

McGuire, Michelle, et al. “Protein.” Nutritional Sciences, Fourth ed., Cengage Learning, Boston, MA, 2016, pp. 185-222.

Signs You’re Not Getting Enough Protein | WebMD.com (16 November 2020).

Why Older Adults Should Eat More Protein (And Not Overdo Protein Shakes) | KHN.org (2019 Jan 17).