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The Power of Protein - Part 1: Protein and Health Concerns

Written by Tom Nikkola - Director of Nutrition & Weight Management

Improved recovery. Decreased body fat. Decreased cravings. Improved satiety. Increased bone density. Increased lean body mass. Enhanced immunity. Improved workout performance. More regular blood-sugar levels. Burn more calories.

If the phrases above were written on the label of a nutritional supplement (and if it were true), that supplement would fly off the shelf. Fortunately, we can find something in our regular diet to provide these benefits; dietary protein. Recently, protein has been getting more and more attention. Some studies are showing that putting more emphasis on protein intake has a significant impact on recovery, body fat levels, cravings, immunity, and more. To keep from writing a whole book, this topic will be broken down over a series of posts. Before addressing the many benefits of consuming the right amount of protein, we'll take look at some of the common concerns and fears associated with higher levels of protein intake. Future posts will discuss the benefits of increased dietary protein, types of protein, timing of intake, recommended intake amounts, and other related topics. Similar discussions will take place with carbohydrates and fat.

Many of the potential concerns related to protein intake have been passed on and on through the years without research to back up the concerns. The most common concerns discussed about protein concern the following three topics:

  • Kidney Function
  • Bone Health
  • Cancer Risk

Kidney Function

If you ask the average person if there are any health risks of consuming too much protein, the most likely response is will be something to the effect of, "it's bad for the kidneys." The reality is there is no evidence of excess protein consumption causing kidney problems in healthy individuals. For those that suffer from chronic kidney disease, it is best to limit protein consumption. Unfortunately, the recommendation for those suffering from chronic kidney disease, has been passed along to include healthy individuals. The most current research shows that protein intake beyond the recommended daily allowance (RDA) does not negatively affect the functioning of the kidneys. Some physiological changes do take place in the kidneys with increased protein consumption, but they are normal changes associated with a change in diet (1).

Bone Health

Another common perception of protein intake is it negatively affects bone density. This is based more on a theory than any documented research. In fact, most research points to the fact, additional protein intake can actually improve bone health. More than likely, decreases in bone density come from a diet lacking fruits and vegetables and high in processed foods, than from too much protein. Studies show that protein intake above the RDAs is important for those on restricted-calorie diets, where loss of bone density is common. Animal protein is associated with higher serum levels of insulin-like growth factor (IGF-1), which is important for bone metabolism. Also, in the process of aging, protein, calcium and Vitamin D intake are important to reduce bone loss (2).

Cancer Risk

In the past decade, there has been more research done to investigate the correlation of protein intake and cancer risk. As with other studies, it is difficult to isolate actual protein intake and look at cancer risk, because people's diets contain so many variables. As an example, there is a significant difference in nutrient intake from commercial beef, and grass-fed, free-range beef. The same could be said of other animal proteins, eggs, and dairy. The average American diet may be higher than average in protein, but the protein in the diet is high in processed meats, added fats, trans-fats, high-fructose corn syrup, and many other ingredients that could be detrimental to health. It isn't practical to look at today's diet and pick one part out of it to correlate with health problems.

In a study published in 2006, researchers looked at the fact that increased levels of IGF-1 could increase the growth of cancer. Increasing protein intake increased IGF-1. Therefore they theorized that increasing protein intake increases cancer risk (3). Unfortunately, IGF-1 levels are just one piece of the cancer puzzle, and as mentioned in the section on bone health, increased IGF-1 is necessary for improving bone density.


There is no doubt that our diet can have a significant impact on our health. Human studies on protein intake do not show increased rates of disease for those that are generally healthy. Of course, the protein sources should be low in saturated fat and should come from unprocessed sources. Logically, it's best to avoid processed meat, much like it's best to avoid processed fats and carbohydrates (4). There are actually many benefits to replacing some of the carbohydrates in ones diet with protein, for healthy individuals and for athletes (5). Benefits of regular intake of lean protein will be discussed in a future post, along with various types and sources of protein, timing of intake, and other related topics that can help you optimize your health and fitness.

Go to: Part 2 - Protein and Body Composition

Go to: Part 3 - Recommended Intake and Protein Sources


1. William F Martin, Lawrence E Armstrong, and Nancy R Rodriguez. Dietary protein intake and renal function. Nutr Metab (Lond). 2005;2:25. Published online 2005 September 20. doi: 10.1186/1743-7075-2-25. PMCID: PMC1262767

2. Robert P Heaney and Donald K Layman. Amount and type of protein influences bone health. Am J Clin Nutr. Vol. 87, No. 5, 1567S-1570S, May 2008

3. Fontana, Luigi, Klein, Samuel, Holloszy, John O. Long-term low-protein, low-calorie diet and endurance exercise modulate metabolic factors associated with cancer risk. Am J Clin Nutr. 2006 84:1456-1462


5. McDonald, Lyle. The Protein Book. Lyle McDonald Publishing.

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