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Medical [Medical] The Risk of High Protein Diets
2014.03.11 13:37
| The Risk of High-Protein Diets Two studies indicate that they may do more harm than good By KEVIN HELLIKER (WSJ) Updated March 10, 2014 9:29 p.m. ET New research suggests there may be benefits from minimizing consumption of animal-based protein. ⓒ Hall/SoFood/Corbis Research shows that a diet high in protein and low in carbohydrates can help shed pounds and normalize blood-glucose levels, improvements that lower the risk of diabetes and cardiovascular disease. But will you live longer on a high-protein, low-carb diet? Two studies in the current edition of the scientific journal Cell Metabolism suggest the opposite. One involved an experiment conducted on mice, the other an 18-year study of humans who had divulged their dietary habits. Both studies found a strong association between longevity and a low-protein, high-carbohydrate diet, although the human study bore a twist: Beyond age 65, higher protein levels appeared to promote longevity. "Those high-protein diets were developed with a shortsighted vision," said Valter D. Longo, a University of Southern California professor of gerontology and biological sciences and the lead author of the human study. "On a high-protein, high-fat diet you can lose weight, but in the long run you may be hurting yourself." These studies are anything but definitive, showing only associations derived from highly limited evidence. But in gerontology, the influence of protein consumption on longevity is a hot topic. Last year, the American Federation for Aging Research hosted a symposium on "Optimal Protein Intake for Older Adults," featuring a panel of scientists from academia and industry. No concrete answers emerged, except perhaps that protein consumption influences health in ways that are complex. "High protein diets may be effective to lose weight rapidly," said Elena Volpi, a professor of geriatrics at the University of Texas Medical Branch in Galveston. "But very high protein diets may also be harmful." In the human study, those consuming high levels of plant-based protein had a threefold increase in cancer mortality but no higher rate of overall mortality. Consumers of animal protein had big increases in both. That suggests, as other research has shown, that there may be benefits from minimizing consumption of animal-based protein. "These results indicate that respondents ages 50 to 65 consuming moderate to high levels of animal protein display a major increase in the risks for overall and cancer mortality," the researchers concluded. Consumers are going gaga for protein as food companies race to slap the nutrient on packaging. WSJ's Sarah Nassauer joins Lunch Break to explain why this move is part of a larger trend of consumers demanding to know more about the benefits of the food they eat. Exo Foods makes protein bars with an unusual ingredient: cricket flour. Exo co-founders Greg Sewitz and Gabi Lewis join Lunch Break to explain why they're betting their bars will be a success in the already crowded U.S. marketplace. For subjects 66 and older, the opposite proved true: Higher protein consumption was associated with greater survival. Gerontologists say this makes sense, because the ability to absorb protein appears to diminish in the aging body, requiring perhaps greater consumption. Even then, though, the takeaway is somewhat complicated. Americans tend to consume the bulk of their protein at dinner, and the body isn't always able to process an entire day's worth in one sitting, said Dr. Volpi, who wasn't involved in either study. "It appears you can better use the protein you need if you distribute it across three meals, especially if you are a senior," she said. In one study, 858 mice were fed one of 25 diets with differing ratios of protein to carbohydrates. Those that ate higher ratios of protein were leaner. But they didn't live as long. "Median life span increased (by about 30%) from about 95 weeks to 125 weeks as the protein-to-carbohydrate ratio decreased," said the study, conducted by researchers in Australia. "Our results show that healthy aging is not achieved in mice fed high protein diets." Of course, mice aren't human. Indeed, the Australian researchers acknowledge that the same results may not be achieved in a different strain of mice. The second study followed 6,381 adult humans for 18 years after they completed a nationally administered survey on their food consumption over a 24-hour period. It divided the subjects into three groups: high-protein consumption (20% or more of calories from protein), moderate-protein consumption (10% to 19% from protein) and low-protein consumption (less than 10%). In the 50-to-65 age range, "subjects in the high protein group had a 74% increase in their relative risk of all-cause mortality, and were more than four times as likely to die of cancer when compared with those in the low-protein group," the researchers reported. One prominent diet expert and high-protein opponent, physician Ron Rosedale, saw the studies as vindicating his longtime warning about the risks of excessive protein. But Dr. Rosedale, who advocates a diet high in so-called healthy fats such as those found in avocados, argues that high levels of carbohydrate consumption are no less dangerous. "If people take these studies as a thumbs up for high carbohydrates, that's missing the point," he said. |
Comment 2
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민경탁*65
2014.03.14 08:16
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이한중*65
2014.03.14 11:35
I believe your general understanding regarding diet is sound and good one.
You and I belong to the over age 66 group where we do not have any good data available so each of us has to come up with
own specific diet, individualized, preferably in consultation with the treating physician.
It is true that protein which has much greater molecular weight than carbohydrate creates a lot more burden to our body metabolism
and produces a lot more waste than carbohydrate and fat which becomes a lot more burden to the kidneys particularly when
you have decreased renal function.
Weight loss and poor nutrition in people over age 80 is epidemic in America and affects longevity.
I encourage many of them to eat lots of cheese and eggs as long as their kidney function is ok.
As for cancers in relation to high protein diet, it makes sense as you described.
High protein, high fat western diet is clearly associated with high incidence of colon cancer, diverticulosis and diverticulitis.
The feces stays in colon too long under high pressure and prolongs the possibility of exposure time to carcinogens, etc.
The original Korean diet in moderation and the western diet based on the above facts again in moderation
may be the way we aging Koreans should follow.
Dr. Lee,
This is what I believe.
1.
Colon cancer rate has been known to be high among those who are on western style diet.
High fat, high protein.
We also know that many carcinogens and aromatic esters are fat soluble, not melting in water.
Even some vitamins are only fat soluble.
That is why some cooking method uses butter to fry food material to extract aromas,
e.g. from spices.
Animal protein contains invariably animal fat more than staple grains' vegetable oil.
Protein gives out same amount of calory but body has to process more (?) to convert it into calory.
Then whether you get same amount of calory from protein or carbhydrate,
you loose same amount of weight if you cut down the total calory intake. No?
2.
Recently, my problem has been not to loose weight (working outside too much) and take more
calory daily via more CHO or oil e.g. fish proten and fat containing beans.
I solved my problem by working
part time in hospital again, staying mostly in front of computer or talking to patients,
rahter than moving around too much.
I try to emulate diebetic diet. What do you think doc?