I heard an objection to a Paleo diet: High consumption of protein could cause kidney trouble. I looked at some articles on this on-line, but couldn't wade through all the info.
I answered that its very difficult to prove causality from these types of studies, and a whole host of other factors could be contributing to the phenomena. Certainly they didn't include true traditional or paleo diets in the study.
What is the simple reply?
Sure and excessive consumption of carbohydrate can cause diabetes problems.
There is a fair bit of research on athletes and protein requirements. Tarnopolsky and Lemon have published some of the better papers on the subject.
This paper in IJSNEM also evaluated what levels of protein intake in athletes indicate possible impairment of kidney function. "To conclude, it appears that protein intake under 2.8 g· kg–1 does not impair renal function in well-trained athletes"
2.0 g of protein per kg of bodymass is 160g of protein for an 80kg individual or 32% of the calories on a 2000kcal/day diet. This is roughly equivalent to 1.7 pounds of ground bison.
This is well within the Acceptable Macronutrient Distribution Range for protein as published by the Food and Nutrition Board in 2005. "The AMDR for protein is 10 to 35 percent of energy for adults"
This is also consistent with Cordain and Eatons estimation of macronutrient ratios in worldwide HG diets. "This high reliance on animal-based foods coupled with the relatively low carbohydrate content of wild plant foods produces universally characteristic macronutrient consumption ratios in which protein is elevated (19–35% of energy) at the expense of carbohydrates (22–40% of energy)."
Hey Zohar and Everyone,
AWESOME links and info on this thread!!
I'd only add that clinically speaking the kidney guidelines for reducing protein intake is based on Hoo-hoo, just as the cholesterol-heart-myth is as well. In fact for those on dialysis, a higher protein diet is advised as the this oxidized subpoulation progress faster toward mortality due to malnourishment/low-protein intakes.
--Manninen discusses no data for low protein diet, JISSN 2004.
--Rodriguez et al discuss no data for high protein diet damaging in normal individuals, NM 2004.
--Walrand et al showed in 10days high protein 3g/kg lean mass improved GFR in young folks (older folks require more time for organ improvements IMHO), AJPEM 2008.
--Dr. Frank Hu dispels myths and summarizes evidence high protein better for satiety, thermogenesis and weight loss, JACN 2004. Dr. Hu has switched to the DARK SIDE haa with DR. Wm Krauss (away Harv-tards Willet et al)
--Case study Nielson et al elderly pt prevented end stage renal disease and improved GFR on carb restricted, ~1-1.1 g/kg protein (30%), high fat 50% diet resulted in reversal of eye damage, improved diabetes and halted progressive creatinine (improved GFR actually based on age and improved lean mass, both Cockroft Gault and MDRD formulae), NM 2006.
If one is insulin sensitive (and really no one is -- maybe 10% of the pop who are not damaged by the SAD?), then one can tolerate a lower protein intake 1-1.5 grams/pound body weight daily or lower and have great gains and muscle hypertrophy and optimal health.
For carb intolerant folks (like me), MORE protein is better to COUNTER insulin and increase glucagon improvements, 1-2 grams per pound of body weight can produce HEEYGE gains combined with the right exercise. However there is a point (>25-35%) I believe protein can be too much and will trigger excessive insulin, esp if that person is not doing ANY low level exercise and/or loaded resistance training...
I like how Poliquin has discussed value of high protein for muscles at T-nation. God he cr*cks me the fr*ck up. Basically anything good for muscles (natural speaking, not artificial chemicals) is good also for hormesis cascades, longevity, preventing sarcopenia and for mitochondrial biogenesis.
I remember reading that it was nonsense, however, I am not sure where. I came across this after a quick google search.
"Fact is that there are no studies that have ever shown a high protein diet causing kidney damage in persons with normal kidney function. Only people who already have a pre-existing kidney condition need to be concerned with keeping their protein in check." -- http://bodybuilding.about.com/od/bodybuildingfaq/f/kidneydamage.htm
And the same so called 'experts' say fat will give you atheroschlerosis! Perhaps according to said experts, we should all just subsist exclusively on fiber, cheerios, and expensive medicines from big pharma... -Eva
Interestingly, my aunt has been paleo for about a year, and is now having similar kidney trouble. they're not sure why... her doctor has advised her to stay away from meat. Thinks its caused by too much protein. She's definitely bummed.
i'll keep you posted.
The notion that human kidneys are ill-equipped to handle the digestion of pastured meat is too absurd to respond to. Now, if we're talking about massive amounts of whey protein via milkshake, then I might buy it.
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