Why Did Doctors Keep Prescribing Cancer?

We’ve known about the role of estrogen in breast cancer going back to the 1800s, when surgical removal of the ovaries seemed to help in some cases. Ovaries were said to send out “mysterious” influences to the rest of the body, which were identified as estrogen in 1923. The medical profession jumped on this discovery and started injecting menopausal women by the thousands, and it was said that “[t]he ‘shot’ gives a ‘respectable’ hook on which to hang the visit to the doctor…” Soon, there were pills and patches, and medical journals like the Journal of the American Medical Association regaled doctors with ads I feature in my video How Did Doctors Not Know About the Risks of Hormone Therapy? on how they can “help the women to happiness by simply prescribing estrogen” and, “[w]hen women outlive their ovaries…,” there is Premarin.

As far back as the 1940s, concerns were raised that this practice might cause breast cancer, noting it would have been nice to figure this out before we started dosing women en masse. But breast cancer risk didn’t seem to matter as much, because heart disease was the number-one killer of women, reviews concluded, and because women taking hormones appeared to have lower heart attack rates, which would outweigh any additional breast cancer. However, women taking estrogen tended to be of a higher socioeconomic class, exercised more, and engaged in other healthy lifestyle changes like consuming more dietary fiber and getting their cholesterol checked. So, maybe that’s why women taking estrogen appeared to be protected from heart disease. Perhaps it had nothing to do with the drugs themselves. Despite the medical profession’s “enthusiasm for estrogen replacement therapy,” only a randomized clinical trial could really resolve this question. We would need to divide women into two groups, with half getting the hormones and half getting a placebo, and follow them out for a few years. There was no such study…until the 1990s, when the Women’s Health Initiative study was designed.

Wait a second. Why did it take the bulk of a century to decide to definitively study the safety of something prescribed to millions of women? Perhaps because there had never been a female director of the National Institutes of Health until then. “Just three weeks after being named NIH Director in 1991, [Bernadine Healy] went before Congress to announce, ‘We need a moon walk for women.’ That ‘moon walk’ took the form of the Women’s Health Initiative, the most definitive, far-reaching clinical trial of women’s health ever undertaken in the United States.”

The bombshell landed in summer 2002. There was so much more invasive breast cancer in the hormone users that they were forced to stop the study prematurely. What about heart disease? Wasn’t that supposed to balance things out? The women didn’t just have more breast cancer—they had more heart attacks, more strokes, and more blood clots to their lungs.

The news that women treated with hormone replacement therapy “experienced higher rates of breast cancer, cardiovascular disease, and overall harm has rocked women and physicians across the country.” Estrogen started out as the most prescribed drug in America before the study, but, after, the number of prescriptions dropped immediately and, within a year, so did the incidence of breast cancer in the United States.

The most important question about this story is why were we all so surprised? There had been “decades of repeated warnings” about the risks of cancer. In fact, the reason breast cancer patients had so much trouble suing the pharmaceutical company was that “the drugs have contained warning labels for decades.” And, with that disclosure, surely any reasonable physician would have included it in their risk and benefit discussions with their patients, right? It’s like the warning labels on packs of cigarettes. If you get lung cancer now, you should have known better. And, so, if you were on hormone replacement therapy and got breast cancer, don’t blame the drug company. They warned you about the risks, right there in the fine print.

Why didn’t more doctors warn their patients? Even after the study came out, millions of prescriptions continued to be dispensed. That’s a lot of cancer in our patients we caused, wrote one doctor. “How long will it take us to discard the financial gains, to admit that we are harming many of our patients, and to start changing our prescription habits?”

“Why did this practice continue in the face of mounting evidence of harm?” Well, it is a multibillion-dollar industry. “Despite an overwhelming amount of evidence to the contrary, many physicians still believe that estrogenic hormones have overall health benefits,” a “non-evidence-based perception [that] may be the result of decades of carefully orchestrated corporate influence on medical literature.” Indeed, “[d]ozens of ghostwritten reviews and commentaries published in medical journals and supplements were used to promote unproven benefits and downplay harms of menopausal hormone therapy…” PR companies were paid to write the articles that were then passed off as having been written by some expert.

What now? “Gynecologists must switch allegiance from eminence-based to evidence-based medicine.” In other words, they must consider what the science says and not just what some so-called expert says. It’s been said that the “current culture of gynecology encourages the dissemination of health advice based on advertising rather than science.”

“Women were placed in the way of harm by their physicians, who acted as unsuspecting patsies for the pharmaceutical companies.” If we really wanted to prevent heart attacks in women, simple lifestyle behaviors can eliminate more than 90 percent of heart attack risk. So, instead of being Big Pharma’s pawns, “recommending a healthful diet, increased exercise, and smoking cessation would truly benefit women’s health.”


The whole Premarin debacle speaks to the importance of putting purported therapies to the test (see, for example, Do Vitamin D Supplements Help with Diabetes, Weight Loss, and Blood Pressure?), as well as to the power of Big Pharma (Eliminating Conflicts of Interest in Medical Research), medical community collusion (American Medical Association Complicity with Big Tobacco), and my most series on mammograms.

What about Plant-Based Bioidentical Hormones and Soy Phytoestrogens for Menopause Hot Flashes? Check out the videos to find out.

In general, patients (and doctors) tend to wildly overestimate the efficacy of pills and procedures. See Why Prevention Is Worth a Ton of Cure and The Actual Benefit of Diet vs. Drugs.

Medical care, in general, may be the third leading cause of death in the United States. See How Doctors Responded to Being Named a Leading Killer.

In health,
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:

The Effects of the Hops Phytoestrogen in Beer on Breast Cancer Risk

Hops have been used for centuries as a flavoring agent in beer, but “[o]ver the years, a recurring suggestion has been that hops”—and therefore beer—may be estrogenic, thanks to a potent phytoestrogen in hops called 8-PN, also known as hopein. Might beer drinking affect our hormones? I discuss this in my video What Are the Effects of the Hops Phytoestrogen in Beer?.

Even just the alcohol in beer can reduce testosterone levels in men, so when beer was tested as a source of estrogens, the alcohol was first removed. Researchers tested the equivalent of one can of beer every day for a month on the hormone levels of postmenopausal women, so as to not confound the results with her own estrogens, and they found significant alterations of hormonal levels during the beer month and then a return to baseline a week afterwards. But does this have any clinical effects, whether good or bad?

A cross-sectional study of about 1,700 women found that beer drinkers appear to have better bone density, perhaps because of the pro-estrogenic effects. They don’t recommend women start drinking beer for bone health, but suggest it may have beneficial bone effects for women who already drink.

What about helping with hot flashes? About half of postmenopausal and premenopausal women in the United States suffer from hot flashes, whereas the prevalence in Japan may be ten times lower, presumed to be because of their soy consumption. What about hops? There have been a few studies showing potential benefit, leading to a 2013 review suggesting that “hop extract may be somewhat effective in treating menopausal discomforts especially against hot flushes,” but that was before a study reported extraordinary results with about a half teaspoon of dried hop flowers. In the placebo group, the women started out having 23 hot flashes a week and continued to have 23 hot flashes a week throughout the three-month study. In the hops group, the women started out even worse with about 29 hot flashes a week, but then got down to 19 at the end of the first month, then 9, and finally just 1 hot flash a week. And similar findings were reported for all the other menopausal symptoms measured.

Animal estrogens work, too. Millions of women used to be on horse hormones—Premarin, from pregnant mares’ urine. That drug also took care of hot flashes, as well as  curtailed osteoporosis, but caused a pesky little side effect called breast cancer. Thankfully, when this was realized and millions of women stopped taking it, breast cancer rates fell in countries around the world.

The question, then, is: Are the estrogens in hops more like the breast cancer-promoting horse estrogens or the breast cancer-preventing soy estrogens? The key to understanding the health-protective potential of soy phytoestrogens is understanding the difference between the two types of estrogen receptors, alpha receptors and beta receptors. Unlike animal estrogen, the soy phytoestrogens bind preferentially to the beta receptors, and in breast tissue, they’re like yin and yang with the alpha receptors signaling breast cell proliferation. This explains why horse hormones increase breast cancer risk, whereas the beta receptors, where the soy binds, oppose that proliferative impact. So, do the hops phytoestrogens prefer beta, too? No. 8-PN is a selective estrogen receptor alpha promoter. “Surprisingly and in clear contrast to genistein [the soy], 8-PN is a much weaker” binder of beta than of alpha. So, that explains why hops is such a common ingredient in so-called breast enhancing supplements—that is, because it acts more like estrogen estrogen. Given the breast cancer concerns, use of such products should be discouraged, but just drinking beer could provide the exposure to the hops estrogen, which could help explain why beer may be more carcinogenic to the breast than some other forms of alcohol.


A phytoestrogen in beer? For more on the background of this issue, see The Most Potent Phytoestrogen Is in Beer.

Other videos on phytoestrogen include:

To learn more about dietary effects on testosterone, see:

What about “natural” hormones for menopause? See my video Plant-Based Bioidentical Hormones.

For more on the risks of alcohol in terms of breast cancer risk, see Breast Cancer and Alcohol: How Much Is Safe? and Breast Cancer Risk: Red Wine vs. White Wine.

In health,
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:

Almonds vs. Rice vs. Potatoes for Osteoporosis

Currently, an estimated ten million Americans suffer from osteoporosis, causing more than a million fractures, including hundreds of thousands of hip fractures, a common reason people end up in nursing homes. Many older women say they’d rather be dead than break their hip and end up in a home.

Bone is a living, “dynamic organ that is constantly renewed through a process of remodeling and modeling” involving bone breakdown by cells that eat bone, called osteoclasts, and bone formation by cells that build bone, called osteoblasts. Osteoporosis is caused by an imbalance between bone loss and bone gain, most often related to hormonal changes that occur during menopause. Is there anything we can do to help tip the balance back in bone’s favor?

There are a number of specific compounds in plant foods that look promising, but, as I discuss in my video Almonds for Osteoporosis, they are based on in vitro studies where researchers basically just drip some plant compound like cranberry phytonutrients on bone cells in a petri dish and see a boost in bone-builder cells or a drop in bone-eater cells. But no matter how much people like cranberry sauce, they’re not injecting it into their veins. For phytonutrients to reach the bone, they first have to get absorbed from the digestive tract into our bloodstream and make it past the liver before they can circulate to our skeleton. So, what we need is a so-called ex vivo study, where you take people, feed them a food—or not, draw their blood a few hours later, and then drip their blood onto bone cells to see if there’s any difference.

Normally, I’m not impressed with studies funded by marketing boards that pay for studies like the one that found that eating almonds improved cycling distance and athletic performance—compared to cookies. But the study I discuss in my video mentioned above was brilliant, not surprisingly, given it was performed in the world-famous lab of Dr. David Jenkins. There was a population study that suggested that eating almonds could protect against osteoporosis. Researchers could have simply dripped some almond extract on bone cells, but that’s not testing the whole food. Instead bone cells could be treated with the blood obtained from donors who had been fed the whole food to directly test the effects of these foods at the cellular level.

So, researchers exposed human osteoclasts, the bone-eating cells, to blood obtained before and four hours after eating a handful of almonds. But, wait. If you ate a handful of almonds every day, wouldn’t you gain weight? That’s almost 200 calories a day. Women in one study added to their regular diet a handful of almonds—like 35 nuts—as a mid-morning snack and were instructed to eat as much as they wanted for lunch and dinner that day. What happened? They ate less. In fact, they ate so much less, they canceled out the nut calories. In the study, the participants all had the same breakfast and then 0, 173, or 259 calories’ worth of almonds as a snack, before eating as much lunch and dinner as they wanted. The nuts appeared to be so satiating that the subjects ate less for lunch or dinner such that, at the end of the day, there was no significant difference in total caloric intake amongst any of the three groups. Part of the reason we don’t tend to gain weight when adding nuts to our diet may be because we end up flushing nearly one third of the calories down the toilet because we just don’t chew well enough. This is why we think there’s so much less fat in our bloodstream after eating whole almonds compared to the same amount of almond oil taken out of the same quantity of nuts.

Back to the study: So, researchers wanted to see if they could suppress the activity of the cells that eat away our bones. What did they find? Blood “serum obtained following the consumption of an almond meal inhibits human osteoclast formation, function, and gene expression…[providing] direct evidence to support the association between regular almond consumption and a reduced risk of developing osteoporosis.” The researchers also tried before and after eating other meals, including rice and potatoes, to make sure there wasn’t just some effect of eating in general. But, no: The protective effect did appear specific to the almonds.


What about dairy products? See my Is Milk Good for Our Bones? video.

And what about calcium supplements? Check out Are Calcium Supplements Safe? and Are Calcium Supplements Effective?.

Surprised by the lack of weight gain from eating all those nuts? You won’t be after watching Nuts and Obesity: The Weight of Evidence. And if you think that’s surprising, Pistachio Nut for Erectile Dysfunction will really shock you.

Want to learn more about ingenious ex vivo studies? See:

One possible mechanism for why nuts may be so healthy for our bones can be found in my video Phytates for the Prevention of Osteoporosis. What about the power of prunes? See Prunes for Osteoporosis.

In health,
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: