Chapter 97
Getting Rid of Excess Estrogen
Over the last 50 years, more than half a million women have participated in ten randomized mammography trials, each with ten years of follow-up. What does the science say? Let’s imagine 1000 asymptomatic women at average risk were randomized either not to participate in screening or to be screened every two years starting at 50 in accordance with USPSTF recommendations. Over the next 20 years, we would get 200 false alarms (though these would lead to only 30 biopsies), three cases of cancer would be missed, but 15 false positive cases would be found, which would mean that these women would be incorrectly diagnosed with breast cancer and unnecessarily treated. (A third danger, namely breast cancer from the x-rays used in mammography, is not taken into account in the model, since only indirect estimates exist that assume one to five cancer cases per 10 000 women). In contrast, thanks to mammography two deaths from breast cancer would be prevented, but overall no lives would be saved.
Women who were surveyed believed that mammography halves the risk of dying from breast cancer and saves the life of about every twelfth woman. In fact, over ten years about five thousandths of women without regular mammography screening die of breast cancer, whereas with screening it is only four thousandths. Isn’t the life of one out of 1000 women worth all that? But even that may not even be true. None of the ten randomized trials found an improvement in overall mortality, which means that probably no lives are saved. How can that be? If ten years of screening saves one out of 1000 women from death due to breast cancer, the only way to arrive at a total of zero lives saved is that mammography somehow leads to the death of one out of 1000 healthy women. This is where overdiagnosis comes into play.
The fact is that some tiny tumors discovered through mammography would never have progressed, and some would even have disappeared on their own. Autopsies of accident victims show that 7 to 39 percent of women between 40 and 70 are walking around with tiny breast tumors, 96 percent of which will never grow further or kill them. So if these tumors had not been detected during a preventive exam, these women might never have been affected by them—or even known they had them. But if cancer is discovered on a mammogram, it has to be treated, because you don’t know what it’s going to do. And that treatment comes with all the risks that unnecessary surgery, chemotherapy, and radiation entail.
Unnecessary radiation treatments to the chest increase the risk of dying from heart disease and lung cancer, which could explain why mammography kills as many people as it saves. Those who are cured afterward become the most passionate advocates of mammography because they believe it saved their life. In reality, the more likely scenario—and the two- to ten-times more likely scenario—is that the treatment did nothing because the cancer would not have caused harm. So they endured all the pain and suffering for nothing. That is the irony of mammography: The people who are harmed the most are the ones who most emphatically claim that it helps.
I am not against mammography. But I am against the paternalism that pushes women to get mammograms without being fully informed about the benefits and risks. Some women will still decide to do it, others won’t. The decision is yours.
Getting Rid of Excess Estrogen
There is so much confusion among the public about mammography that most people believe it prevents cancer or at least lowers the risk. Of course, a preventive exam does not change cancer risk. The good news is that the same dietary and lifestyle changes that can protect against breast cancer also protect against the most common cause of death, cardiovascular disease, which ten times more women in the United States die of—about 400 000 each year; for breast cancer it is 40 000 women.
In the Harvard Nurses’ Health Study, in which more than 150 000 women and their dietary habits were observed over decades, researchers found that those who ate more plant and fewer animal foods developed breast cancer significantly less often—even after accounting for factors such as weight, hereditary predisposition, alcohol consumption, and physical activity. In addition, a plant-based diet seemed to protect particularly against the deadliest types of tumors. The California Study with more than 90 000 women came to similar conclusions, including a significantly lower breast cancer risk with a plant-based diet, especially for the tumors that are hardest to treat.
Women’s estrogen levels both before and after menopause are closely linked to breast cancer risk, which may explain the entire association between excess body fat and breast cancer. (Estrogen produced by fat tissue enters the bloodstream.) Does that explain why people eating a plant-based diet, who on average are leaner, have a lower breast cancer risk? Studies found an average lower estrogen level in vegetarian women before and after menopause that cannot be explained solely by their leaner build. It could be due to higher fiber intake.
Our body gets rid of excess estrogen the same way, evolutionarily, that we also get rid of cholesterol—it dumps it into the digestive tract, because that’s where the fiber is that grabs it and takes it out with it. Without fiber, excess hormones (and cholesterol) simply get back into the bloodstream, but our body assumes that the intestines are packed with fiber from morning to night, because that’s how it always was over the course of evolution. We only began eating meat once we built tools, but plants generally don’t run that fast, so the bulk of our diet was fiber. It is estimated that our prehistoric ancestors ate seven times as much fiber as we do today.
Researchers at the university where I studied medicine published a study in the New England Journal of Medicine in which vegetarians and non-vegetarians “were given plastic bags and coolers with dry ice for three 24-hour fecal collections.” Vegetarians excrete two to three times more estrogen every day because they have two to three times greater “fecal output.” So avoiding hormone pills is only one way to reduce breast cancer risk. The other is to get rid of excess estrogen the way nature intended.
The Best and Worst Foods for Menopause Symptoms
The lower estrogen level of women who eat predominantly plant-based can protect against breast cancer, but do the women perhaps suffer from worse menopause symptoms? Quite the contrary, so they enjoy all the benefits. They report significantly fewer bothersome menopause symptoms, including vasomotor symptoms such as hot flashes and night sweats and other physical symptoms such as muscle and joint pain, fatigue, sleep disturbances, reduced strength and endurance, lethargy, skin changes, weight gain, facial hair, bloating, and frequent urination or incontinence. The researchers concluded: “A plant-based diet can help women in menopause if they want to manage their symptoms with natural means.”
Which foods might ease symptoms? Fruit, vegetables, soy, and plant omega-3-containing foods such as flaxseed correlated with milder symptoms, while meat-heavy diets, dairy products, and omega-3 fatty acids from fish were associated with more severe menopause symptoms. Berries, leafy greens, and vegetables overall seemed to be decisive, however. A study from 2020 examined the connection between diet and menopause symptoms. And found that women who ate a higher-quality diet and ate more fruit, vegetables, and whole grains generally suffered less—not only from vasomotor and physical symptoms, but also from psychological symptoms, sleep disturbances, and bladder and genital complaints. On the other hand, diets high in ultra-processed foods, sweets, meat, and saturated fatty acids were associated with more severe symptoms.