Dietary Protein and Your Kidneys
If I hear one more registered dietician or physician mention that diets high(er) in protein are dangerous, I am going to go postal. First lets make of a list of things that ARE dangerous:
1. Putting your finger in an electrical socket
2. Swimming in a pool full of sharks.
3. Responding “yes” whenever your significant other asks you, “does this make me look fat?”
4. Watching a Ben Affleck movie
Those are dangerous. Diets high in protein are NOT dangerous, as many fitness professionals would have you believe. Many claim that high protein diets will strain or damage the kidneys. Thing is, there has NEVER been one scientific study that has shown that diets high(er) in protein (in this case, upwards of 1 gram per lb of body weight) harm the kidneys in any way in HEALTHY individuals. I’m more likely to date Angelina Jolie than you are in finding a study which says high protein diets cause damage in the kidneys. READ: not going to happen.
And while there are “some” studies which do in fact say that high protein diets cause renal (kidney) dysfunction…..they were done on people who already had some sort of renal disease in the first place. Well duh!!!!
The term “higher” refers to a diet that has people (athletes or active individuals) consuming more than the general populations’ average intake of approximately 15% of energy from protein, e.g., as much as 30%-35%, which is within an Acceptable Macronutrient Distribution Range (AMDR). The RDA states that 0.8 grams per kg of bodyweight per day is acceptable for all healthy individuals. However, what people fail to realize is that the RDA’s recommendations are directed to those people who do nothing but sit on their butt all day. 0.8 grams per kg of body weight is what the RDA recommends to stay alive. It’s just enough to stave of deficiency. That’s great, but that amount doesn’t come close to meeting the needs and requirements of athletes and/or those people who consistently workout.
Athletes, as well as those people who lead an active lifestyle consistently eat diets that are higher in protein compared to what the RDA recommends. Bodybuilders from way back in the 1950’s and 60’s ate higher protein diets (upwards of 300-500 grams PER DAY) and to my knowledge, there has never been a epidemic of kidney disease in these populations; even to this day. NOTE: I am NOT suggesting that you need to ingest 300-500 grams of protein per day, just trying to make a point.
Of relevance to “active” individuals and those in clinical practice is the fact that higher protein diets have quite consistently been shown to result in greater weight loss, greater fat loss, and preservation of lean mass as compared with “lower” protein diets. A framework for understanding dietary protein intake within the context of weight loss and athletic performance is laid out throughout TONS of literature and is beyond the scope of this blog entry.
All in all, high protein diets DO NOT harm or cause any undue strain on the kidneys. And if I wasn’t convincing enough,
In a review titled, “Dietary protein intake and renal function,” published in Nutrition and Metabolism, September 2005, Martin et al concluded, and I quote:
“While protein restriction may be appropriate for treatment of EXISTING renal disease, we find no significant evidence for a detrimental effect of high protein intakes on kidney function in healthy persons after centuries of a high protein Western diet.”