Protein Power

We hear it a lot in the media these days: ways to get more protein, protein heavy diets, new protein shakes.  It’s like the media feels the need to push protein at us every second they get the chance.  But do we really need to be adding more protein in our diets?  Do we even know why we need protein to begin with?

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What is protein?

Biologically speaking, proteins are polymers constructed from the same set of 20 amino acids which are found in a chain form.  A protein consists of one or more polypeptides, amino acid chains, which fold and coil into a specific three dimensional shape.  Each shape gives each protein its unique function within the human body.  Although proteins might not seem like they’re that prevalent in our bodies, they actually account for more than 50% of the dry mass of most cells and are crucial for the function of almost everything we do.  For example, enzymes are made up entirely of proteins and regulate our body’s metabolism among other chemical reactions (Campbell et al. 2008).   Protein also composes the hemoglobin which carries the oxygen you need in your blood system.  In fact, believe it or not, there are over 10,000 proteins inside of you making you who you are today (Harvard 2015).

Four levels of protein structure showing the chains of amino acids folding into protein shape. http://www.boundless.com

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So why exactly do we need protein?       

Protein from the food we eat is broken down into the amino acids we need during digestion, which is why we need to consume protein in our diets in order to remain healthy.  In fact, we require 20 amino acids to make proteins.  We can make about half of these ourselves, but there are nine specifically that need to come through food sources.  These amino acids are therefore called essential amino acids.

The 9 essential amino acids and the 11 non-essential amino acids.

Protein is needed to help our bodies repair cells and make new ones (Medline 2015).  A diet that provides insufficient amounts of one or more essential amino acids is therefore unable to do this and causes protein deficiency, usually seen in the form of malnutrition.  Malnutrition can result in many medical issues including growth failures, loss of muscles, decreased immunity, heart and respiratory problems, and even death.  (Campbell et al. 2008, Harvard 2015).

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How much protein should you get?

Different sources all state different numbers for how much protein you should be getting, but the general consensus is that you should be consuming around 0.36 grams for every pound you weigh.  However, sometimes this varies if you are trying to lose weight or if you are very active (Harvard 2015).  If you are attempting to lose weight, you need 0.36 grams per pound minimum but not more, since your calorie intake is going to be less. If you’re very active, you should be getting more protein per pound overall (Steiman, 2012).

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Can we get too much protein?

There seems to be some debate on this topic.  Some sources say that yes, too much protein can be bad for your kidneys, while others say that the body just breaks down the excess without any problems. So what is the real answer?

According to an article in men’s heath, every time you eat at least 30 grams of protein (which is about what you would consume with an average meat meal) your body launches into protein synthesis which lasts about three hours.  Any more protein than that does not do anything extra for your body.  In fact, eating a meal with 90 grams of protein provides the same benefits as a meal with 30 grams.  So, it’s suggested that you eat your daily amount protein throughout the day instead of just at one meal.  In fact, starting your day with a protein packed breakfast is shown to help people reduce their calorie intake by around 200 calories (Steiman 2012).

However, if you consume way too much protein in your diet, one article quotes it being over 35% of your total calories, and you are restricting other parts of your diet, you can in fact have adverse effects.  This is because the excess protein can lead to the buildup of ketones, which are made when the body begins to use its own storage of fat cells for fuel (mostly in the absence of carbohydrates in a diet).  Ketones are harmful to the kidneys in that they can cause water to be lost through the kidneys and can cause kidney disease or failure (Steiman 2013).

Of course, this is in extreme situations, and in an average person’s diet, there is no need to be concerned about over consumption of protein.

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What foods are good sources of protein?

Amino acids come in two forms: complete amino acids and incomplete amino acids.  Proteins from animal products such as meat, eggs, and cheese are complete amino acids, meaning that they provide all the essential amino acids in their proper portions.  Most plant proteins however are incomplete amino acids, which mean that they are deficient in one or more essential amino acids.  Therefore, vegetarians need diets with a mix of vegetables that provide all the types of amino acids needed for the human body (Campbell et al 2008).

Fish are a great source of complete amino acids and they also provide omega-3 fatty acids which are beneficial for your health as well.

Good sources of incomplete amino acids include soy, beans, quinoas, legumes, nut butters, and some grains.  However, research to determine the best mix of these incomplete amino acids should be done so you know that you are getting your complete set of amino acids daily.

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Have you heard any myths about protein intake?  Do you count how much protein you get every day?  Let me know your thoughts on today’s topic in the comments below.

Until next time,

Kat

Sources:

Campbell N.A., Reece J.B, Urry L.A., Cain M.L., Wasserman S.A., Minorsky P.V., Jackson R.B.  (2008). Biology. Eighth Edition.  Pearson.

Harvard T.H. Chan. (2015). Protein. The Nutrition Source. http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/

Medline Plus. (2015). Protein in Diet.  http://www.nlm.nih.gov/medlineplus/ency/article/002467.htm

Stoppler M.C. MD. (2013). How Much Dietary Protein to Consume. Medicinenet.  http://www.medicinenet.com/how_much_dietary_protein_to_consume-page2/views.htm

Steiman, Adina. (2012). The Truth About Protein.  Men’s Health. http://www.menshealth.com/nutrition/truth-about-protein