Is Soy Healthy for Breast Cancer Survivors?

Soyfoods have become controversial in recent years,…even among health professionals,…exacerbated by misinformation found on the Internet.” Chief among the misconceptions is that soy foods promote breast cancer, because they contain a class of  phytoestrogen compounds called isoflavones. Since estrogens can promote breast cancer growth, it’s natural to assume phytoestrogens might too.

But, people don’t realize there are two types of estrogen receptors in the body—alpha and beta. And, unlike actual estrogen, soy phytoestrogens “preferentially bind to and activate [estrogen receptor beta]. This distinction is important, because the 2 [types of receptors] have different tissue distributions…and often function differently, and sometimes in opposite ways.” And, this appears to be the case in the breast, where beta activation has an anti-estrogenic effect, inhibiting the growth-promoting effects of actual estrogen—something we’ve known for more than ten years. There’s no excuse anymore.

The effects of estradiol, the primary human estrogen, on breast cells are completely opposite to those of soy phytoestrogens, which have antiproliferative effects on breast cancer cells, even at the low concentrations one gets in one’s bloodstream eating just a few servings of soy—which makes sense, given that after eating a cup of soybeans, the levels in our blood cause significant beta receptor activation.

So, where did this outdated notion that soy could increase breast cancer risk come from? The concern was “based largely on research that showed that [the main soy phytoestrogen] genistein stimulates the growth of mammary tumors in [a type of] mouse.” But, it turns out, we’re not actually mice. We metabolize soy isoflavones very differently from rodents. The same soy leads to 20 to 150 times higher levels in the bloodstream of rodents. The breast cancer mouse in question was 58 times higher. So, if you ate 58 cups of soybeans a day, you could get some significant alpha activation, too. But, thankfully, we’re not hairless athymic ovariectomized mice, and we don’t tend to eat 58 cups of soybeans a day.

At just a few servings of soy a day, with the excess beta activation, we would assume soy would actively help prevent breast cancer. And, indeed, “[s]oy intake during childhood, adolescence, and adult life were each associated with a decreased risk of breast cancer.” Those women who ate the most soy in their youth appear to grow up to have less than half the risk.

This may help explain why breast cancer rates are so much higher here than in Asia—yet, when Asians come over to the U.S. to start eating and living like Americans, their risk shoots right up.  For example, women in Connecticut—way at the top of the breast cancer risk heap—in their fifties have, like, ten times more breast cancer than women in their fifties living in Japan. But, it’s not just genetic, since when they move here, their breast cancer rates go up generation after generation, as they assimilate into our culture.

Are the anti-estrogenic effects of soy foods enough to actually change the course of the disease? We didn’t know, until the first human study on soy food intake and breast cancer survival was published in 2009 in the Journal of the American Medical Association, suggesting that “[a]mong women with breast cancer, soy food consumption was significantly associated with decreased risk of death and [breast cancer] recurrence.” Followed by another study, and then another, all with similar findings.

That was enough for the American Cancer Society, who brought together a wide range of cancer experts to offer nutrition guidelines for cancer survivors, to conclude that, if anything, soy foods should be beneficial. Since then, two additional studies have been published, for a total of five, and they all point in the same direction. Five out of five, tracking more than 10,000 breast cancer patients.

Pooling all the results, soy food intake after breast cancer diagnosis was associated with reduced mortality (meaning a longer lifespan) and reduced recurrence—so, less likely the cancer comes back. Anyone who says otherwise hasn’t cracked a journal open in seven years.

And, this improved survival was for both women with estrogen receptor negative tumors and estrogen receptor positive tumors, and for both younger women, and for older women. Pass the edamame.

Doctor’s Note

This is probably the same reason flax seeds are so protective. See Flax Seeds & Breast Cancer Survival: Epidemiological Evidence and Flax Seeds & Breast Cancer Survival: Clinical Evidence.

What about women who carry breast cancer genes? I touched on that in BRCA Breast Cancer Genes & Soy, and it’s the topic of my next video, Should Women at High Risk for Breast Cancer Avoid Soy?

What about genetically modified soy? I made a video abut that too; see GMO Soy & Breast Cancer.

Who Shouldn’t Eat Soy? Glad you asked. Watch that video too! 🙂

Not all phytoestrogens may be protective, though. See The Most Potent Phytoestrogen is in Beer and What are the Effects of the Hops Phytoestrogen in Beer?

If you haven’t yet, you can subscribe to my videos for free by clicking here.

In health,
Michael Greger, M.D.

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

Breast Cancer Cells Feed on Cholesterol

Breast Cancer Cells Feed on CholesterolBy: Michael Greger, M.D., NutritionalFacts.Org.

One in eight American women will be diagnosed with breast cancer in her lifetime. There are a number of compounds in plant foods that may protect against breast cancer by a variety of mechanisms. I’ve talked about the benefits of broccoli, flaxseeds, and soy foods before (See Breast Cancer Survival VegetableFlaxseeds & Breast Cancer Prevention, and Breast Cancer Survival and Soy) but a recent German study reported something new. The researchers found that sunflower and pumpkin seeds were associated with reduced breast cancer risk. They initially chalked the association up to the lignans in the seeds (See Breast Cancer Survival and Lignan Intake), but their lignan lead didn’t pan out. Maybe it’s the phytosterols found concentrated in seeds? (See Optimal Phytosterol Source).

There is evidence that phytosterols may be anticancer nutrients and play a role in reducing breast cancer risk. I thought phytosterols just lowered cholesterol? (See How Phytosterols Lower Cholesterol) What does cancer have to do with cholesterol?

Increasing evidence demonstrates the role that cholesterol may play in the development and progression of breast cancer. Cancer feeds on cholesterol. Transformed cells take up LDL, so-called “bad” cholesterol, and it’s capable of stimulating the growth of human breast cancer cells in a petri dish.

The ability to accumulate fat and cholesterol may enable cancer cells to take advantage of people eating high fat and high cholesterol diets and at least partially explain the benefit of a low-fat diet on lowering human breast cancer recurrence. Although the data has been mixed, the largest study to date (highlighted in my video, Cholesterol Feeds Breast Cancer Cells) found a 17% increased breast cancer risk in women who had a total cholesterol over 240 compared to women whose cholesterol was under 160. However, the researchers could not rule out that there may be something else in cholesterol-raising foods that’s increasing breast cancer risk.

Tumors suck up so much cholesterol that LDL has been considered a vehicle for delivering antitumor drugs to cancer cells. Since cancer feeds on cholesterol, maybe we could stuff some chemo into it like a Trojan horse poison pill?

The uptake of LDL into tumors may be why people’s cholesterol levels drop low after they get cancer—the tumor is eating it up. In fact, patient survival may be lowest when cholesterol uptake is highest. “High LDL receptor content in breast cancer tissue seems to indicate a poor prognosis, [suggesting] that breast tumors rich in LDL receptors may grow rapidly [in the body].” We’ve known about this for decades. You can tell that was an old study because, when it was published in the ‘80s, only 1 in 11 American women got breast cancer.

If cholesterol increases breast cancer risk, what about the use of cholesterol-lowering drugs? See Statin Cholesterol Drugs and Invasive Breast Cancer.

More videos on broccoli and soy’s protective effects against breast cancer:

Some I didn’t mention include:

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.

Photo Source: DiseaseProof.com

Breast Cancer Survival Vegetable

Breast Cancer Survival VegetableBy: Dr. Michael Greger, Director of Public Health and Animal Agriculture at the Humane Society of the United States.

A half million Americans are expected to die this year from cancer, equal to 5 jumbo jets crashing… every day. The number of Americans who die from cancer each year is more than all those who have died in all US wars combined. And this happens every single year.

After a cancer diagnosis people tend to clean up their diets. About a third to a half of breast cancer patients, for example, make healthy dietary changes following diagnosis, such as increasing in fruit and vegetable consumption and decreasing meat, fat and sugar intakes. Does it actually help that late in the game? Well, the Women’s Healthy Eating and Living Study was undertaken in few thousands breast cancer survivors to determine if a plant- based, low-fat, high-fiber diet could influence breast cancer recurrence rates and survival.

Previously they famously reported that simple changes—5 or more servings fruits and veggies a day and just like walking 30 minutes a day 6 days a week was associated with a significant survival advantage, cutting risk nearly in half. Note I said fruits and veggies and exercise. Here’s the proportion of women with breast cancer surviving 9 years in the study if they had low fruit and vegetable consumption and low physical activity, or high in one and low in the other. But here’s the survival curve, of those high in both.

And it worked just as well in women with estrogen receptor negative tumors, which normally have twice the mortality… unless, you eat a few fruits and veggies, and taking a few strolls. The “high” should really be in quotes, I mean you could eat 5 servings in a single meal and certainly walk more than like 2 miles a day.

Imagine, for a second, you have been diagnosed with breast cancer. Imagine sitting in that chair, in the doctor’s office, as your doctor gives you the news… But, there’s a new experimental treatment that can cut your chances of dying in the next few years from like 16% down to just 4%. To quadruple their survival rate many women would re-mortgage their homes to fly to some quack clinic in Mexico, would lose all their hair to chemo, but most, apparently, couldn’t stand the thought of eating broccoli.

And indeed that’s what the latest report from the Women’s Healthy Eating and Living Study found, fruits and vegetables may be good, but cruciferous vegetables may be better. For women on tamoxifen, for example, if one of their 5 daily servings of fruits and veggies was broccoli or cauliflower/collards/cabbage or kale, the risk of cancer recurrence may be cut in half.

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.

4 Things To Help Prevent Most Disease

White House Garden Goes Organic For Healthy LifestyleBy: Dr. Michael Greger, Director of Public Health and Animal Agriculture at the Humane Society of the United States.

Though I was trained as a general practitioner, my chosen specialty is lifestyle medicine. Most of the reasons we go see our doctors are for diseases that could have been prevented. But lifestyle medicine is not just about preventing chronic disease—it’s also about treating it. And not just treating the disease, but treating the causes of disease.

If people just did four simple things
Stop Smoking For Your Health

#1 No Smoking

The Obama Family Exercising

#2 Exercise A Half Hour A Day

Michelle Obama Shopping At A Farmers Market For Fruits & Vegetables

#3 Eat a Diet That Emphasizes Whole Plant Foods

Eat Diet That Emphasizes Whole Plant Foods

#4 And Not Become Obese

they may prevent most cases of diabetes and heart attacks, half of strokes, and a third of cancers. Even modest changes may be more effective in reducing cardiovascular disease, high blood pressure, heart failure, stroke, cancer, diabetes, and all-cause mortality than almost any other medical intervention.

The key difference between conventional medicine and lifestyle medicine is instead of just treating risk factors, we treat the underlying causes of disease, as Drs. Hyman, Ornish, and Roizen describe in their landmark editorial Lifestyle medicine: treating the causes of disease. Doctors typically treat “risk factors” for disease by giving a lifetime’s worth of medications to lower high blood pressure, elevated blood sugar, and high cholesterol. But think about it: high blood pressure is just a symptom of diseased and dysfunctional arteries. We can artificially lower blood pressure with drugs, but that’s not treating the underlying cause. To treat the underlying cause, we need things like diet and exercise, the “penicillin” of lifestyle medicine (See Lifestyle Medicine: Treating the Causes of Disease).

As Dr. Dean Ornish is fond of saying, disregarding the underlying causes and treating only risk factors is somewhat like mopping up the floor around an over-flowing sink instead of just turning off the faucet, which is why medications usually have to be taken for a lifetime. As Dr. Denis Burkitt described, “if a floor is flooded as a result of a dripping tap, it is of little use to mop up the floor unless the tap is turned off. The water from the tap represents the cost of disease, and the flooded floor represents the diseases filling our hospital beds. Medical students learn far more about methods of floor mopping than about turning off taps, and doctors who are specialists in mops and brushes can earn infinitely more money than those dedicated to shutting off taps.” And the drug companies are more than happy to sell rolls of paper towels so patients can buy a new roll every day for the rest of their lives. Paraphrasing poet, Ogden Nash, modern medicine is making great progress, but is headed in the wrong direction.

When the underlying lifestyle causes are addressed, patients often are able to stop taking medication or avoid surgery. We spend billions cracking patients’ chests open, but only rarely does it actually prolong anyone’s life. Instead of surgery, why not instead wipe out at least 90% of heart disease through prevention? Heart disease accounts for more premature deaths than any other illness and is almost completely preventable simply by changing diet and lifestyle, and the same dietary changes required can prevent or reverse many other chronic diseases as well.

So why don’t more doctors do it?

One reason is doctors don’t get paid to do it. No one profits from lifestyle medicine, so it is not part of medical education or practice. Presently, physicians lack training and financial incentives, so they continue to do what they know how to do: prescribe medication and perform surgery.

After Dean Ornish proved you could open up arteries and reverse our number one cause of death, heart disease, with just a plant-based diet and other healthy lifestyle changes (see Resuscitating Medicare and Our Number One Killer Can Be Stopped), he thought that his studies would have a meaningful effect on the practice of mainstream cardiology. After all, he had found a cure for our #1 killer! But, he admits, he was mistaken. “Physician reimbursement,” he realized, “is a much more powerful determinant of medical practice than research.”

Reimbursement over research. Salary over science. Wealth over health. Not a very flattering portrayal of the healing profession. But if doctors won’t do it without getting paid, let’s get them paid.

So Dr. Ornish went to Washington. He argued that if we train and pay for doctors to learn how to help patients address the real causes of disease with lifestyle medicine and not just treat disease risk factors we could save trillions of dollars. And that’s considering only heart disease, diabetes, prostate and breast cancer. The Take Back Your Health Act was introduced in the U.S. Senate to induce doctors to learn and practice lifestyle medicine, not only because it works better, but because they will be paid to do it. Sadly, the bill died, just like millions of Americans will continue to do with reversible chronic diseases.

By treating the root causes of diseases with plants not pills, we can also avoid the adverse side effects of prescription drugs that kill more than 100,000 Americans every year, effectively making doctors a leading cause of death in the United States. See One in a Thousand: Ending the Heart Disease Epidemic and my live presentation Uprooting the Leading Causes of Death.

For those surprised that policy makers wouldn’t support such a common sense notion as preventive health, check out my video The McGovern Report. What about medical associations? Medical Associations Oppose Bill to Mandate Nutrition Training.

There is another reason that may explain why the medical profession remains so entrenched. See my video The Tomato Effect.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations More Than an Apple a Day and From Table to Able.

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.

Video Sources

Photo Sources: Obama Eating Fruit, Michelle Obama Shopping, Obama Family Exercising

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