Animal Protein May Play a Role in Cancer Risk

In the two decades between 1990 and 2010, the leading causes of death and disability remained relatively constant. Heart disease remains the leading cause of loss of health and life, but among the diseases whose incidence has increased the most over the past generation is chronic kidney disease. The number of deaths has doubled.

Our “meat-sweet” diet has been implicated in this escalation. Excess table sugar and high-fructose corn syrup consumption is associated with increased blood pressure and uric acid levels, both of which can damage the kidney. The saturated fat, trans fat, and cholesterol found in animal products and junk food are also associated with impaired kidney function, and meat protein increases the acid load to the kidneys, boosting ammonia production and potentially damaging our sensitive kidney tissue. This is why a restriction of protein intake is often recommended to chronic kidney disease patients to help prevent further functional decline.

Is all protein created equal? No—not all protein has the same effect on your kidneys. Our kidneys appear to handle plant protein very differently from animal protein. Within hours of consuming meat, our kidneys rev up into hyperfiltration mode, dramatically increasing the kidneys’ workload. This is true of a variety of animal proteins—beef, chicken, and fish appear to have similar effects. But an equivalent amount of plant protein causes virtually no noticeable stress on the kidneys. Eat some tuna, and within three hours, your kidney filtration rate can shoot up 36 percent. But eating the same amount of protein in the form of tofu doesn’t appear to place any additional strain on the kidneys.

Why does animal protein cause the overload reaction while plant protein doesn’t? Researchers discovered that after giving subjects a powerful anti-inflammatory drug along with animal protein, the hyperfiltration response disappeared, suggesting the hyperactive response was triggered by inflammation.

Animal protein may also play a role in cancer risk. IGF-1, insulin-like growth factor 1, is a cancer-promoting growth hormone that is released in excess when we eat animal protein. This is presumably why those who eat less meat, egg white, or dairy proteins have significantly lower levels circulating within their bodies within weeks of making the dietary switch. This lowering of IGF-1 levels is thought to be why the blood of men and women eating plant-based diets suppresses prostate and breast cancer growth in vitro significantly better than those eating the Standard American Diet.

In health,
Michael Greger, M.D.

Dr. Michael Greger on Breast Cancer Authority Blog

Michael Greger, M.D., is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.

Relieving Yourself of Excess Estrogen – Dietary Habits For Breast Cancer Prevention

Vegetarian Diet Helps Prevent Breast Cancer By: Michael Greger, M.D., a physician, author, and internationally recognized professional speaker.

Earlier this year a study was published comparing the hormonal levels of women with and without breast cancer. If estrogen makes most breast cancers grow, then one would expect that the levels of both estrogen would be higher in women who have breast cancer compared to women who don’t, or at least who don’t yet.

And indeed, no surprise, that’s what they found, significantly more estradiol freely circulating through their bloodstream of those with breast cancer. But the study also looked at diets and hormonal levels. These were all omnivores. The women eating vegetarian did even better.

This may help explain why, in a study of the “relative risks for breast cancer by levels of animal product consumption”, there appears to be a trend between lower breast cancer risk the more vegetarian someone eats. And it was researchers at my medical alma mater Tufts that figured out why, in a landmark article published in the New England Journal of Medicine.

See, the way your body gets rid of excess cholesterol is to dump it into the digestive tract knowing full well that there will be lots of fiber in there to grab it, hold onto it, and flush it out the body. (hopefully you chew a little better than that).

We did, after all, evolve quite a long time before Twinkies and Wonder Bread, and royal institutions such as Burger King and Dairy queen. So our body just expects it. It just assumes our intestines are going to be packed with fiber all day long—7 times more than we’re getting now. We certainly did evolve eating some meat, but plants don’t tend to run as fast and so the bulk of our diets was made up, of a lot of bulk.

And that’s how our body gets rid of excess estrogen. Vegetarian women have increased fiber input, which leads to “vegetarian women having an increase fecal output, which leads to increased excretion of estrogen and a decreased blood concentration of estrogen.”

And this just wasn’t in theory, they measured it. “Subjects were provided with plastic bags and insulated boxes filled with dry ice for thee 24 hour fecal collections.” You’ve hear of popsicles, well they had them make more like, poopsicles.

And here you go: In any one 24 hour period, the vegetarians were fecally excreting more than twice as much estrogen as the omnivores.

And, measuring the estrogen excretion versus the size of the fecal output, you can see, the bigger the better. See heavyweight V’s versus the welterweight Os? No wonder vegetarian women in the United States have been found to have such lower rates of breast cancer.

It’s great that many women stopped HRT, stopped taking extra estrogens. Well, another way to rid yourself of excess estrogens is in the way nature intended.

Video Sources

Mills PK, Beeson WL, Phillips RL, Fraser GE. Dietary habits and breast cancer incidence among Seventh-day Adventists. Cancer. 1989 Aug 1;64(3):582-90.

Goldin BR, Adlercreutz H, Gorbach SL, Warram JH, Dwyer JT, Swenson L, Woods MN. Estrogen excretion patterns and plasma levels in vegetarian and omnivorous women. N Engl J Med. 1982 Dec 16;307(25):1542-7.

Aubertin-Leheudre M, Hamalainen E, Adlercreutz H. Diets and hormonal levels in postmenopausal women with or without breast cancer. Nutr Cancer. 2011 May;63(4):514-24.

Michael Greger M.D.About Michael Greger M.D.
Michael Greger, M.D., is a physician, author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous “meat defamation” trial. Currently Dr. Greger proudly serves as the Director of Public Health and Animal Agriculture at the Humane Society of the United States.

Related Article:

Estrogen Dominance and Xenoestrogens

10 Ways to Reduce Risk of Breast Cancer

Estrogenic Cooked Meat Carcinogens

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