Proteins

Topics Covered:

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What are proteins?

Proteins are macronutrient compounds that contain amino acids. Many foods that we eat or the liquids that we drink contain complete proteins (animal-based products & soy) or incomplete proteins (plant-based products).  

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What does protein do for us?

Proteins can provide us with amino acids or, if absolutely needed, they can be used as energy. 

After consumption, our bodies breakdown external proteins in order to free their amino acids. These “free” amino acids are then reorganized and used to build and repair muscles, organs, teeth, bones, and skin. Basically amino acids are the building blocks of life. These newly rebuilt proteins can also transport nutrients in and out of our cells, regulate our metabolism, facilitate chemical reactions, fight infections, and help balance our pH (acid-base) levels.

1 protein gram = 4 calories (energy units)

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What types of foods contain protein?

Proteins can naturally be found in foods such as eggs, milk, meat, fish, tofu, nuts, legumes, grains, vegetables and fruit.

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What is the Recommended Daily Allowance (RDA)?

10-20% of your daily calorie intake should consist of proteins. Consult with a dietitian to obtain your total daily calories intake (serious athletes should consume 8 grams of protein for every 20 pounds of body weight).

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Are there health risks associated with proteins?

Our bodies need protein (amino acids) to sustain life. Unfortunately, when the amino acids aren’t used, the nitrogen in the amino acid is excreted (in our urine); nitrogen cannot be stored. This fat cannot later be used to create protein because the nitrogen is missing. As a consequence, if our diets do not provide enough amino acids, our bodies will breakdown the protein from muscle and the less important organs to obtain the needed nitrogen to sustain life;   As you can tell, this is extremely unhealthy and can cause major side effects.

As noted above, nitrogen is lost if unused, but the rest of the amino acid strand – the carbon, hydrogen, and oxygen – is converted into fat, which can lead to unwanted weight gain. However, the major concern for too much protein consumption is not weight gain, but rather the side effects of the package it comes in. For example, beef contains high amounts of protein, but also contains high amounts of saturated fats. Therefore, higher consumption of beef means higher consumption of saturated fats, and saturated fats increase the bad (LDL) cholesterol in our bloodstream, which leads to heart disease.

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References:

  1. Boyle, Marie A., and Sara Long. Personal Nutrition, Seventh Edition California, Wadsworth College Learning, 2010.
  2. “Dietary Proteins.” U.S. National Library of Medicine. Retrieved April 15, 2011  <http://www.nlm.nih.gov/medlineplus>
  3. “Protein: Moving Closer to Center Stage.” Harvard School of Public Health. 2011. April 15, 2011 <http://www.hsph.harvard.edu/nutritionsource/index.html>
  4. Carpi, Anthony Ph.D. “Fats and Proteins.” Visionlearning. 2003. Retrieved May 30, 2011 <http://www.visionlearning.com>

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Disclaimer

Reasonable care has been taken in preparing this document, and the information provided herein is believed to be accurate. However, this information is not intended to constitute an “authoritative statement” under Food and Drug Administration rules and regulations.

General Safety Advisory

The information is not intended to be a substitute for professional medical advice. It is important to seek the advice of a physician about any medical condition or symptom. It is also important to seek the advice of a physician, registered dietitian, pharmacist, or other qualified health professional about the appropriateness of taking dietary supplements and their potential interactions with medications.