Will too much protein ruin my kidneys?

The topic of high dosages of protein and kidney damage is always on the news and in magazines, but there is no solid scientific evidence to back this! [caption id="attachment_3750" align="aligncenter" width="650"] Topical - how much protein is too much for your kidneys?[/caption] A recent article in the Daily Mail shares some good information on the importance of eating adequate protein, but the headline installs false belief. ‘Eating too much protein can strain your kidneys but too little is bad for your muscles – so are YOU getting the right amount?’

In defence of your kidneys

To quote Alan Aragon, an evidence-based nutritionist: ‘Back in 1983, researchers first discovered that eating more protein increases your “glomerular filtration rate,” or GFR. Think of GFR as the amount of blood your kidneys are filtering per minute. From this finding, many scientists made the leap that a higher GFR places your kidneys under greater stress. What science really shows: Nearly 2 decades ago, Dutch researchers found that while a protein-rich meal did boost GFR, it didn’t have an adverse effect on overall kidney function. In fact, there’s zero published research showing that downing hefty amounts of protein—specifically, up to 1.27 grams per pound of body weight a day—damages healthy kidneys.’ Other studies examining bodybuilders with protein intakes of 2.8g/kg vs. moderate protein intakes revealed no significant differences in kidney function between the groups – “there is no reason to restrict protein in healthy individuals.” (1) Kidney health is also not improved and no benefits, to kidney health, are shown from low proteins diets either. (2) So please do not believe all you read in the media as most of the headlines, in the media, are exaggerated and based on observational experiments, and we need to understand correlation does not mean causation.

So How Much Protein Do I Need?

Unless calories are dropping very low protein will remain constant throughout your weight loss/gaining phase and should stay in the range of 1-1.5g/lb of lean body weight. (3)

How do you know your lean body weight?

The easiest is an estimate, but do not sweat it. Going off total body weight will not have huge implications.

References

1. Poortmans JR, Dellalieux O. Do regular high-protein diets have potential health risks on kidney function in athletes?Int J Sports Nutr 2000;10:28-38.
2. Klahr S, Levey AS, Beck GJ et al. The effects of dietary protein restriction and blood-pressure control on the progression of chronic renal failure.N Engl J Med 1994;330:877-884.
3. Eric R Helms,Alan A Aragon and Peter J Fitschen. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition 2014, 11:20.