By: Dr. Michael Greger, Director of Public Health and Animal Agriculture at the Humane Society of the United States.
A hundred years ago the New York Times reported on a rather sophisticated study for the time, 4,600 cases of cancer studied over 7 years, suggesting that the increased consumption of animal foods was to blame. A century later, the latest review on the subjects concluded that mortality from all causes put together, ischemic heart disease, and circulatory and cerebrovascular diseases was significantly lower in those eating meat-free diets, in addition to less cancer and diabetes.
I’m surprised they found such significant results given that people in these studies typically didn’t stop eating meat until late in life. For example, in the largest study done up until that time, up to a third ate vegetarian for less than 5 years, yet they still ended up with lower rates of heart disease whether they were young or old—under 60, or over 60, whether they were normal weight or overweight, whether they used to smoke or never smoked, those that had stopped eating meat had lower risk, suggesting that decades of higher risk dietary behavior could be reversed within just years of eating healthier.If you look at countries that switched from eating traditional, more plant-based diets, to more Westernized diets, it may take 20 years for cancer rates to shoot up. It takes decades for most tumors to grow. For example if you look in Asia, their dietary shift was accompanied by a remarkable increase in mortality rates of breast, colon, and prostate cancers. For example death from breast cancer in Japan or from prostate cancer, the line just goes straight up, but again it can take years of a cancer promoting diet and lifestyle. Same thing shown with migration studies. Men moving from rural China to the U.S. experience a dramatic increase in cancer risk, but tumors take time to grow.
So it’s remarkable to me that after most of a lifetime eating the standard western diet, one can turn it around, reverse chronic disease risk with a healthier diet, even late in the game.
So, should we all start eating vegetarian? This was the editorial that accompanied the results from the largest study ever published on Americans eating plant-based diets that found vegetarian diets associated with lower all-cause mortality, meaning those who started eating vegetarian live, on average, longer lives. Now this analysis included so-called semi-vegetarians, who ate meat at least once a month (but no more than once a week), so it’s not yet clear how bad eating meat a few times a month is. What we can all agree on, though, is that we should limit our intake of junk food and animal fat, and eat more fruits and vegetables. Most authorities will also agree that diets should include whole grains, beans, and nuts. Instead of fighting over who’s diet’s the best, it’s time to acknowledge these common features of diets associated with less disease and instead focus our attention on helping patients avoid the intense commercial pressures to eat otherwise.
How amazing the human body is if we just treat it right! This reminds me of videos like Lifestyle Medicine: Treating the Causes of Disease or How Many Meet the Simple Seven? where simple changes can lead to tremendous differences in health outcomes. So please don’t allow the perfect to become the enemy of the good. Any movement we can make towards improving our diet can help. Though the earlier the better: See Heart Disease Starts in Childhood and Back in Circulation: Sciatica and Cholesterol.
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.
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F L Growe, P N Appleby, R C Travis, T J Key. Risk of hospitalization or death from ischemic heart disease among British vegetarians and nonvegetarians: results from the EPIC-Oxford cohort study. Am J Clin Nutr. 2013 Mar;97(3):597-603.
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