Essential Health Info

Protein & the 8 Roles it has in the Human Body


Protein Origins

The human body is incredible.  There are thousands of unique proteins in our body.  In this very moment, your protein-rich body enables you to sit, walk, run, and even hold your head up so you can read this article.  They are the body’s power source.  Without adequate amounts, infections could raid your body, your immune system would be weak, and your digestion would not work.  They are the building blocks of our cells.  Proteins function as eight roles in the body (Blake, 2019, pp. 190-199):

  • Structural support for the body
  • Build enzymes and hormones
  • Balances fluid in the body
  • Acts as a buffer to stabilize the body’s PH
  • Transports substances
  • Create antibodies
  • Provides energy
  • Increases satiety

 Amino Acid Sequence & Digestion

All proteins are made up of an amino acid sequence.  They are linked together to make a unique sequence.  Each chain of amino acids have a certain length with a special function.  The body’s internal environment, for instance water, can have great affect on the amino acid chain.  Therefore, the effects of our internal environment can alter the shape it.  Altering its shape will change its function in the body.  Altogether, amino acids are like numeric digits like a bank pin or telephone number (pp 109).

Your body has a limited amount of both nonessential and essential amino acids.  For instance, your cells carry these amino acid pools throughout the blood (pp. 190).  The body cannot synthesize nine of these essential acids, but there are eleven nonessential that can.  The body synthesizes, or combines different parts of broken down amino acids to make a new one.  Also, some of these amino acids are broken down to make nonprotein substances like thyroid hormones and melanin.  In fact, the body turns over 200 grams of protein a day so that your body is in balance.  Think about it.  If your body breaks down 200 grams of protein a day, then how much it should you consume on a daily basis for your body to function?

The 8 Roles of Protein

  1. It provides structural & mechanical support to help maintain the body’s tissues.  For instance, it keeps you upright moving, and flexible (pp. 196).  In addition to regular maintenance, more protein is needed for healing wounds or emergency repair (pp. 196).
  2. It builds most enzymes and several hormones. Anytime our body needs a reaction to happen quickly such as digestion, it directs enzymes to act as a catalyst to speed up the reaction.  Also, though enzymes cause quick reactions, hormones are the proteins that direct signals to turn on or off enzyme reactions (pp. 197).
  3. It helps maintain fluid balance 50-75% of our body is made up of water.  Therefore, it helps distributes the water throughout many compartments of the body (pp. 197)
  4. It helps maintain acid-base balance Proteins can alter the pH level of the body’s fluids.  It acts as a buffer by receiving or donating hydrogen ions in the blood.  We do not want our blood to become too acidic or too alkaline (pp. 198).
  5. It transports substances throughout the body.  Transport proteins transport oxygen, waste products, vitamins, and some minerals such as potassium and sodium through our blood.  Through a protein channel, some of these nutrients can come into and out of the cell (p. 198).
  6. It helps our immune system.  There are particular proteins called antibodies that bind and neutralize foreign substances in the body.  In a way, these antibodies are the “soldiers” that protect our immune system (pp. 199)
  7. It provides energy.  As one of the last lines of defense, it will break down into glucose to provide our body with energy.  However, it only happens in serious cases.  For instance, when our body does not have adequate amounts of nutrients in our diet (pp. 199).
  8. It provides satiety and appetite control.  Protein increases our feeling of fullness after a meal.  Therefore, eating a meal with a good source of protein will cause you to feel more satisfied than a similar meal in calories.  More specifically, a meal with a higher ratio of carbohydrates (pp. 199).


The most important fact to note about protein sufficiency is knowing how much to consume in your daily diet.  Many times we read online articles that provide science based content as to why this nutrient is good for health, muscles, and even weight loss in regards to food.  However, the body needs adequate amounts to consume on a day to day basis for more than just food.  The recommended dietary intake takes into consideration a person’s age and weight.  Yet, did you know that protein is also calculated through PDCAAS?  This stands for protein digestibility corrected amino acid score.  It measures as a percentage that takes into account both digestibility and amino acid profile to provide a numeric quantity of daily intake (pp. 203).

Ages 14-18 yrs, needs 0.85g/kg a day

Ages greater than 19 yrs, needs 0.80g/kg a day

Your weight in kilograms: __________ kg x 0.8g (or 0.85g) = __________ g/day

(convert your weight into kilograms by dividing pounds by 2.2 or see link below)


Author:  Jamie Moore Senior at Sam Houston State University Pre-Nursing

Works Cited

Blake, J. S. (2019). Nutrition & You (5th Edition) (5th ed.). Pearson.


Leave a Comment