Nutrition & Diet Coach

Peggy Korody North San Diego Registered Dietitian

Protein – How much and what’s your source?

Written By: Peggy Korody - Sep• 17•11

Protein intake has been on my mind a lot lately for a couple of reasons. One reason is many people have a misconception of how much protein is needed on a daily basis.  Second, which is of more concern to me, is a study in Consumer Reports regarding protein powder and drinks.  First let’s talk a bit about protein, what it does, how much we need, etc.

Basically, the role of protein in food is not to provide protein for the body, but to supply amino acids from which the body can make proteins (Understanding Nutrition; Whitney Rolfes, Sixth Edition). These new proteins are then used for growth, repair and replacement of tissues.  So how do we calculate how much protein a body needs?  After all, we are all different sizes, performing different levels of activity, etc. — so is there a “one size fits all” approach?  The RDA (Recommended Daily Allowance) for protein is 0.8-g/kg-body weight.  For example a 110 lb. person would need 40 grams of protein a day (110 ¸ 2.2 = 50 kg x 0.8 = 40 grams protein).  This may be shocking to you, but 40 grams of protein is only 1.41 ounces!

Some people may be thinking that if they are an athlete, work out, lift weights, or run, their protein needs are much higher. marathonrunnersAlthough it is true the amino acids derived from the protein we eat are used to fuel our muscles, their contribution is much lower than that of carbohydrates and fat.  In fact, as a general rule only about 5% of the body’s general energy needs, including the energy needs of exercising muscles, is supplied by the metabolism of amino acids.  Endurance exercise, such as 2-hour marathon running uses the most protein at roughly 10-15%.  A normal diet can easily provide enough protein to supply the fuel the body needs, hence supplements are not needed, contrary to what athletes believe (source: American College of Sports Medicine and others: Nutrition and Athletic Performance, Medicine & Science in Sports & Exercise).   It is often recommended that athletics consume 1.2 to 1.4 gram of protein per kg of body weight. Which would calculate out to 60 – 70 grams or 2.2 – 2.47 ounces for our 110 lb. person, which is easily attainable from our diet.

Personally, I do not know anyone who consumes less than 3 ounces of protein a day. So what happens to all this excess protein we intake?  Basically, if the amino acids are not needed for growth, repair, replacement, or energy, they go through a process known as deamination.  This process strips the nitrogen from the protein and excretes it, the remaining carbon fragments are then converted to fat and stored for later use in healthy individuals.  A person with kidney disease or other chronic illness may not be able to achieve this process, which is a whole other subject!

Regarding the issue of Consumer Reports, their study found “worrisome levels of lead, cadmium, and other metals” in popular protein

eas mysoplex

supplements. The popular protein drinks tested included a total of 15 products including Muscle Milk and EAS Myoplex.  They had an independent lab (U.S. Pharmacopeia (USP), look for this symbol on any supplement you take) test these products for contaminants including arsenic, cadmium, lead, and mercury.  Most products were in the low to moderate range but three products stood out.  These products were EAS Mypolex Original Rich Dark Chocolate Shake, Muscle Milk chocolate powder and Muscle Milk vanilla crème.  To see the actual statistics visit http://www.webmd.com/food-recipes/news/20100603/report-protein-drinks-have-unhealthy-metals. Of course the industry disagrees with the study acknowledging that their products do contain these substances, but possibly not at the level tested.  The problem is that often people consume more than the recommended amount, increasing the amount of containments in their body.  Why worry?  Excess cadmium and protein can damage your kidneys, while lead intake can result in brain and nerve damage.

Protein in our diet is important and it is easily attainable in the amount needed from the foods we eat. According to Consumer Reports a “better, cheaper way to bulk up” is to have: half of a chicken breast (27 grams protein at 62 cents), three 8-ounce glasses of milk (23 grams protein at 60 cents), and three scrambled eggs (20 gram protein at 46 cents) totaling 70 grams protein for a mere $1.68.  Or you could have one scoop of Nitro-Tech (25 grams protein) at $1.61.  Which would you rather have?

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