New research on high protein diets and kidney function

For your reading pleasure:
New research on high protein diets and kidney function
POSTED BY: Monica Reinagel, M.S., LD/N | December 07, 2009 | 10:52 AM

High protein diets are in these days. I talked about some of the reasons why in a recent episode of my weekly podcast. For one, they seem to increase satiety (decrease hunger sensations) on a reduced-calorie diet.

However, there are lingering concerns over whether all that protein strains the kidneys. A recent study measured the effects of high and normal protein diets on kidney function. For the study, a small group of young, healthy volunteers ate either normal- or high-protein diets for 7 days. The researchers reported "significant" changes in kidney function in the high protein group and concluded that "more attention should be paid to the potential adverse renal effects of HP diets."

Hey, more research into "potential adverse effects" is always good. But the effects observed in this study weren't that alarming.

Interestingly, both diets fell within the range recommended by the Institute of Medicine. The IOM recommends that protein make up 10 to 35% of calories. In this study, the normal protein group was getting about 15% of calories from protein; the high protein group about 30%.

Does this mean that the IOM recommendations need to be adjusted? Probably not.

My questions:

1. What happens when you continue eating a higher protein diet for more than seven days? Are the changes in kidney function just a temporary blip as the body adjusts to a change in diet?

2. So what? The differences observed were statistically significant, but not necessarily meaningful. Kidney function in both groups was well within the normal range. All in all, the changes that the researchers noted are the ones you'd expect if you change the composition of the diet and none of them seem particularly worrisome.

Nonetheless, expect this study to show up in the media translated roughly thus: "High protein diets may damage kidneys."

Note: High protein diets are definitely not recommended for anyone with kidney disease.

I guess this means I eat a "high" protein diet @ 30% protein, lol.

Thank you for this link Ange. It highlights how inferior journalism has gotten ("it will show up as...") and how research studies can be skewed to favor the interpretors biased view. In this case... high protein diets are harmful to kidney function.
In fact this study was the beginning of the beginning of research to find a meaningful conclusion.
Carry on with your diets people.

I find it interesting that they felt 7 days was long enough to even report about - particularly if the only thing they have to say about it afterward is "more research needs to be done."

Yes, I agree with both of you. I'm glad that people are at least investigating, and are actually defining what a "high protein" intake was. I find a lot of reviews don't even define what constitutes high protein, or high fat... wtf??!! No wonder there is so much confusion and argument.

Darilyn - it's probably a small research done cheaply: the point is to prove that there is a reason to do more research (and therefore give funds). Many medical studies start out that way since you wouldn't allocate funds if there was no change. (Medical research is expensive).

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There has been this myth about high-protein diets placing strain in the kidneys for quite some time now. The only problem, as normal, is that none of the anaemic experts can put down their tofu for long enough to explain exactly what the problem is.

Admittedly, it is true that patients with compromised kidney function do not respond well to a high-protein diet. Mainly because their kidneys do not work properly... If you pour water into a broken bath, you may get a leak - but that doesn't mean you shouldn't put water in baths!

Humans have evolved one a diet that would now be considered high-protein. However, if this was acknowledged by the authorities then those producing all the 'low-fat' goodies would lose a lot of money.

Regards, Marek
London Nutritionist