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 Healthiest Way to Eat Paleo

There have been about a half dozen studies published on Paleo-type diets, starting around 20 years ago. For example, in what sounds like a reality TV show: ten diabetic Australian Aborigines were dropped off in a remote location to fend for themselves, hunting and gathering foods like figs and crocodiles.

In Modern Meat Not Ahead of the Game, my video on wild game, I showed that kangaroo meat causes a significantly smaller spike of inflammation compared to retail meat like beef. Of course, ideally we’d eat anti-inflammatory foods, but wild game is so low in fat that you can design a game-based diet with under 7 percent of calories from fat. Skinless chicken breast, in comparison, has 14 times more fat than kangaroo meat. So you can eat curried kangaroo with your cantaloupe (as they did in the study) and drop your cholesterol almost as much as eating vegetarian.

So, how did the “contestants” do? Well, nearly anything would have been preferable to the diet they were eating before, which was centered on refined carbs, soda, beer, milk, and cheap fatty meat. They did pretty well, though, showing a significantly better blood sugar response—but it was due to a ton of weight loss because they were starving. Evidently, they couldn’t catch enough kangaroos, so even if they had been running around the desert for seven weeks on 1,200 daily calories of their original junky diet, they may have done just as well. We’ll never know, though, because there was no control group.

Some of the other Paleo studies have the same problem: They’re small and short with no control groups, yet still report favorable results. The findings of one such study are no surprise, given that subjects cut their saturated fat intake in half, presumably because they cut out so much cheese, sausage, or ice cream. In another study, nine people went Paleo for ten days. They halved their saturated fat and salt intake, and, as one might expect, their cholesterol and blood pressure dropped.

The longest Paleo study had been only 3 months in duration, until a 15-month study was conducted—but it was done on pigs. The pigs did better because they gained less weight on the Paleo diet. Why? Because they fed the Paleo group 20 percent fewer calories. The improvement in insulin sensitivity in pigs was not reproduced in a study on people, however. Although, there were some benefits like improved glucose tolerance, thanks to these dietary changes: The Paleo group ate less dairy, cereals, oil, and margarine, and ate more fruits and nuts, with no significant change in meat consumption.

A follow-up study also failed to find improved glucose tolerance in the Paleo group over the control group, but did show other risk factor benefits. And no wonder! Any diet cutting out dairy, doughnuts, oil, sugar, candy, soda, beer, and salt is likely to make people healthier and feel better. In my video Paleo Diet Studies Show Benefits, you can see a day’s worth of food on the Standard American Diet, filled with pizza, soda, burgers, processed foods, and sweets, versus a Paleo diet, which, surprisingly, has lots of foods that actually grew out of the ground.

But the Paleo diet also prohibits beans. Should we really be telling people to stop eating beans? Well, it seems hardly anyone eats them anyway. Only about 1 in 200 middle-aged American women get enough, with more than 96 percent of Americans not even reaching the minimum recommended amount. So telling people to stop isn’t going to change their diet very much. I’m all for condemning the Standard American Diet’s refined carbs, “nonhuman mammalian milk”, and junk foods, but proscribing legumes is a mistake. As I’ve noted before, beans, split peas, chickpeas, and lentils may be the most important dietary predictor of survival. Beans and whole grains are the dietary cornerstones of the longest living populations on Earth. Plant-based diets in general and legumes in particular are a common thread among longevity blue zones around the world.

The bottom line may be that reaching for a serving of kangaroo may be better than a cheese danish, “but foraging for…[an] apple might prove to be the most therapeutic of all.”


I’ve reported previously on Paleo’s disappointing results in Paleo Diets May Negate Benefits of Exercise.

The underlying philosophy behind “caveman” diets may be flawed in the first place. See:

So, What’s the Natural Human Diet? Watch the video!

The wild game video I mentioned is Modern Meat Not Ahead of the Game. Kangaroo is kind of the Australian version of venison. Note that it also matters how the animals are killed. See Filled Full of Lead and Lead Contamination in Fish and Game.

And, for more on the musical fruit, see:

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:

What About Canned Fruit?

Food cans used to be soldered with lead compounds—so much so that people living off of canned food may have died from lead poisoning. Thankfully, this is no longer a problem in the United States. Lead contamination was one of the first priorities of the Food and Drug Administration back in 1906, before it was even called the FDA. Newspapers now have online archives going back a century so we can read about landmark historical events like “FDA Proposes Lead-Soldered Cans Be Banned” from way back yonder in…1993. So even though it was a priority in 1906, the ban didn’t actually go into effect until 1995. Evidently it was complicated because lead solder was “grandfathered” in as a “prior-sanctioned” substance.

Now that the lead is gone, though, are canned foods healthy? It depends primarily on what’s in the can. If it’s SPAM or another processed meat product, for instance, I’d probably pass.

What about canned fruit? We know fruits and vegetables in general may help protect us from dying of cardiovascular disease, and, when it comes to preventing strokes, fruit may be even more protective. But whether food processing affects this association was unknown, as I discuss in my video Is Canned Fruit as Healthy? One study found that unprocessed produce, mostly apples and oranges, appeared superior to processed produce. But that study focused mainly orange and apple juice. It’s no surprise whole fruit is better than fruit juice.

What about whole fruit when it is in a can? Dietary guidelines encourage eating all fruit whether it’s fresh, frozen, or canned, but few studies have examined the health benefits of canned fruit…until now. Canned fruit did not seem to enable people to live longer. In fact, moving from fresh or dried fruit to canned fruit might even shorten one’s life. Therefore, perhaps dietary guidelines should stress fresh, frozen, and dried fruit rather than canned.

Why the difference? While there’s no longer lead in cans these days, there is bisphenol A (BPA), the plastics chemical used in the lining of most cans. BPA can leach into the food and might counterbalance some of the fruits’ benefits. Recently, for example, blood levels of this chemical were associated with thickening of the artery linings going up to the brains of young adults. Canned fruit is often packed in syrup, as well, and all that added sugar and the canning process itself may diminish some nutrients, potentially wiping out 20 to 40 percent of the phenolic phytonutrients and about half of the vitamin C.

Maybe one of the reasons citrus appears particularly protective against stroke is its vitamin C content. It appears the more vitamin C in our diet and in our bloodstream, the lower the risk of stroke. And the way to get vitamin C into the bloodstream is to eat a lot of healthy foods, like citrus and tropical fruits, broccoli, and bell peppers. “Therefore, the observed effect of vitamin C on stroke reduction may simply be a proxy for specific foods (eg, fruits and vegetables) that causally lower stroke” risk. How could the researchers tell? Instead of food, they gave people vitamin C pills to see if they worked—and they didn’t.

This might be because citrus fruit have all sorts of other compounds associated with lower stroke risk, proving that the whole is greater than the sum of its parts. You can’t capture Mother Nature in a pill. It’s like the apocryphal beta-carotene story. Dozens of studies showed that people who ate more beta-carotene-rich foods, like greens and sweet potatoes, and therefore had more beta-carotene circulating in their system, had lower cancer risk. What about beta-carotene supplements instead of whole foods? Researchers tried giving beta-carotene pills to people. Not only did they not work, they may have even caused more cancer. I assumed the National Cancer Institute researcher who did this study would conclude the obvious: produce, not pills. But, no. Instead, the researcher questioned whether he should have tried lower dose pills, alpha-carotene pills, pills with other phytochemicals, or maybe multiple combinations. After all, he said, “[i]t is likely that neither the public nor the scientific community will be satisfied with recommendations concerned solely with foods…”


Check out my other videos on the can-lining chemical BPA, including:

Is fresh fruit really that healthy? See:

Is it possible to get too much of a good thing? See How Much Fruit Is Too Much?.

Now that there’s no more lead in the cans, are there any other ways we’re exposed to the toxic heavy metal? I did a whole series on lead, which you can watch. See also:

I close with yet another screed against reductionism. For more on that, see my videos Why Is Nutrition So Commercialized? and Reductionism and the Deficiency Mentality.

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: