High Protein, High Risk?

Low-protein diets are linked to longer life spans in mice and humans.

By | March 6, 2014

FLICKR, TARYN HICKSTwo studies published March 4 in Cell Metabolism suggest that a low-protein diet may be key for longevity, casting doubt on the widespread dietary trend of reducing carbohydrate intake and loading up on protein.

One study, led by Stephen Simpson at the University of Sydney, looked at the life spans of mice on diets containing varying levels of protein, carbohydrates, and fat. Mice on a high-protein diet were leaner, but mice on a low-protein, high-carbohydrate diet lived much longer. The other study, led by Valter Longo of the University of Southern California, used death certificate data from people 50- to 65-years-old who had participated in the national NHANES nutrition survey. NHANES participants who reported a high-protein diet on NHANES had a higher rate of death, especially from cancer before age 65. However, after age 65, a high-protein diet seemed beneficial.

“If these two studies are really correct, what people in general are trying to do . . . might be completely wrong in terms of maintaining health and even longevity,” Shin-ichiro Imai of Washington University in St. Louis told ScienceNow.

Popular nutrition writer Marion Nestle, who is also a public health professor at New York University, is more skeptical of Longo’s results. “Protein is not, and never has been, an issue in American diets, and the data presented in this study do not convince me to think otherwise,” she told the Washington Post.

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Avatar of: vincehradil


Posts: 3

March 6, 2014

I'm skeptical of how well a mouse nutrition study can translate to humans. I would think that metabolism is very different for the two. In the other study, I think they need to look for other correlations. People who have high protein diets probably have other habits in common as well, and the whole lifestyle may cause the trend proposed. Still, interesting results, but we have to be careful not to draw too many conclusions.

Avatar of: goniza


Posts: 1

March 6, 2014

Any diet high in something is bound to be harmful.

Avatar of: ironjustice


Posts: 43

March 11, 2014

I would say this gives very good credence to the herbivore hypothesis? One has a very hard time overdosing on vegetable protein? Protein, high protein, is easily accomplished by eating animal protein though. So, as Dr. Hindhede showed when he did his food studies, man needs only one gram of protein per every ten pounds body weight, in order to survive, and the RDA says, 3.5 grams. So, obviously, the RDA, according to this study, is incorrect?


Avatar of: Mike Pardo

Mike Pardo

Posts: 2

March 13, 2014

What type of animal protein was consumed in the NHANES survey?

A hamburger from McDonalds is NOT the same as beef that came from cows that were grass-fed.  There is a distinct quality difference concering the amount of omega 3 present, less fat, more vitamins A and E, higher levels of antioxidants, and up to seven times the beta-carotene as grain fed beef.  A cow in nature does not eat grain.  I'm not sure why we can't put 2 and 2 together.  If a study compared grass-fed beef vs plant protein showed similar results I would be more apt. to believe it.

Avatar of: ironjustice


Posts: 43

Replied to a comment from Mike Pardo made on March 13, 2014

March 14, 2014

"more vitamins A and E, higher levels of antioxidants, and up to seven times the beta-carotene as grain fed beef"

You actually believe, a dead animals red blood cells bursting, as they die, exposing their inner core, iron, which causes massive oxidation, is going to leave any antioxidants at all in the meat, it isn't going to instantly oxidise all these fatty acids of which you speak? They advise you to eat vegetables with your meat because of the oxidation which is inevitable when one consumes the highly oxidation producing meat.

"A plausible explanation is that lipid peroxyl radicals thus generated, which originated from routine dietary components such as fat and red meat, may contribute, at least in part, to the high incidence of colon cancer"


"protein and iron interact with red wine phenolics during the in vitro digestion and decrease their antioxidant capacity"

Avatar of: ruzzell


Posts: 2

March 16, 2014

Mice seem a poor model for humans in this, and the problem with high-protein diets in our society is the quality of the protein (comes too much from industrial meat, which = high fat, high contaminants).

Avatar of: ironjustice


Posts: 43

Replied to a comment from ruzzell made on March 16, 2014

March 18, 2014

This article though shows by giving 'different' protein source, plant to animal, in a known plant eater, giraffe, changes them for the worse, so you are saying that the giraffe, too, is not a good model for a human being?

"The nutritional contribution to bovine spongiform encephalopathy"


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