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:

The Best Dried Fruit for Osteoporosis

“We are in an epidemic of osteoporosis. There can be no doubt about that.” Ten million Americans have it, and one in three older women will get it. “We urgently need public health strategies to maintain bone health throughout the life cycle and to prevent osteoporosis in later life.” Might fruits and vegetables be the unexpected natural answer to the question of osteoporosis prevention? My video Prunes for Osteoporosis sought to find out.

Evidence from a variety of studies “strongly points to a positive link between fruit and vegetable consumption and indexes of bone health,” such as bone mineral density, and the “size of the effect in the older women [is] impressive: doubling the fruit intake” is associated with a 5 percent higher spine mineralization. The same relationship exists with young women, too. And, eating lots of fruit in childhood may protect bones throughout life—something that was not found for milk intake, as I’ve explored before in my video Is Milk Good For Our Bones?

Bone health isn’t just about calcium. There are several key nutrients found in vegetables, fruits, and beans that are associated with better bone mineral density, but does that translate into lower hip fracture risk? The Singapore Chinese Health Study found that a “diet rich in plant-based foods, namely vegetables, fruit, and legumes such as soy, may reduce the risk of hip fracture.” But, why?

“The underlying mechanism in postmenopausal osteoporosis (PO) is an imbalance between bone resorption [disappearance] and formation,” and oxidative stress may play a role in this balance.

There are two types of bone cells: “the bone-forming osteoblasts and the bone-dismantling osteoclasts.” Osteoblasts are continually laying down new bone, while osteoclasts chisel away old bone, using free radicals as the molecular chisel to chip away our bone. Too many free radicals in our system, though, may lead to excessive bone breakdown. Antioxidant defenses appear “markedly decreased in osteoporotic women,” and “elderly osteoporotic women had consistently lower levels of all natural antioxidants tested than controls.”

“Because excessive [free radicals] may contribute to bone loss, it is important to elucidate the potential role antioxidant-rich fruits play in mitigating bone loss that leads to the development of osteoporosis.” The thought is that fruits up-regulate the bone building cells, and down-regulate the bone-eating cells, tipping the balance towards greater bone mass. So, let’s put a fruit to the test. Which one do we pick? Dried plums were chosen because they have among the highest antioxidant ranking among commonly consumed fruits and vegetables—and because the researchers received a grant from the California Dried Plum Board!

When you think of prunes, you think of bowels, not bones, but, over a decade ago, researchers at Oklahoma State tried giving a dozen prunes a day to a group of postmenopausal women, using a dozen dried apple rings as a control. After three months, only the subjects who consumed the prunes had significant elevations in an enzyme marker of bone formation, although prunes didn’t seem to affect markers of bone breakdown. So, prunes may help more with building bones than preventing bone loss. However, the reverse was found with almonds, so maybe a little prune-and-almond trail mix is in order. 

With this bump in bone formation indices, one might expect that if they did a longer study, we would actually see an impact on bone mineral density. And nine years later, just such a study was done: 12 months on dried plums versus apples. Both dried fruit regimens appeared to have “bone-protective effects,” though the prunes seemed to work better in the arm bone and spine.

So, the dried plum marketing board wants everyone to know that dried plums are “the most effective fruit in both preventing and reversing bone loss,” but only two fruits have ever been tested: plums and apples. If this pans out for other plants, though, “a ‘fruit and vegetables’ approach may provide a very sensible (and natural) alternative therapy for osteoporosis treatment, one that is likely to have numerous additional health-related benefits.” All we have to do is convince people to actually do it.


For more on bone health, see:

What else can prunes do for us? Check out Prunes vs. Metamucil vs. Vegan Diet.

Apple rings have their own benefits. See Dried Apples vs. Cholesterol.

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:

From Adequate Nutrition to Optimum Nutrition

Research in human nutrition over the past four decades has led to many discoveries as well as a comprehensive understanding of the exact mechanisms behind how food nutrients affect our bodies. As I discuss in my video Reductionism and the Deficiency Mentality, however, the “prevalence of epidemics of diet-related chronic diseases, especially obesity, type 2 diabetes, osteoporosis, cardiovascular diseases, and cancers, dramatically increases worldwide each year.” Why hasn’t all this intricate knowledge translated into improvements in public health? Perhaps it has to do with our entire philosophy of nutrition called reductionism, where everything is broken down into its constituent parts; food is reduced to a collection of single compounds with supposed single effects. “The reductionist approach has traditionally been and continues today as the dominant approach in nutrition research.” For example, did you know that mechanistically, there’s a chemical in ginger root that down-regulates phorbol myristate acetate-induced phosphorylation of ERK1/2 and JNK MAP kinases? That’s actually pretty cool, but not while millions of people continue to die of diet-related disease.

We already know that three quarters of chronic disease risk––diabetes, heart attacks, stroke, and cancer—can be eliminated if everyone followed four simple practices: not smoking, not being obese, getting a half hour of exercise a day, and eating a healthier diet, defined as more fruits, veggies, and whole grains, and less meat. Think what that could mean in terms of the human costs. We already know enough to save millions of lives. So, shouldn’t our efforts be spent implementing these changes before another dollar is spent on research such as figuring out whether there is some grape skin extract that can lower cholesterol in zebra fish or even trying to find out whether there are whole foods that can do the same? Why spend taxpayer dollars clogging the arteries of striped minnows by feeding them a high cholesterol diet to see whether hawthorn leaves and flowers have the potential to help? Even if they did and even if it worked in people, too, wouldn’t it be better to simply not clog our arteries in the first place? This dramatic drop in risk and increase in healthy life years through preventive nutrition need not involve superfoods or herbal extracts or fancy nutritional supplements—just healthier eating. When Hippocrates supposedly said, “Let food be your medicine and medicine be your food,” he “did not mean that foods are drugs, but rather, that the best way to remain in good health is to maintain a healthy diet.” (Note: Hippocrates probably never actually said that—but it’s a great sentiment anyways!)

The historical attitude of the field of nutrition, however, may be best summed up by the phrase, “Eat what you want after you eat what you should.” In other words, eat whatever you want as long as you get your vitamins and minerals. This mindset is epitomized by breakfast cereals, which often provide double-digit vitamins and minerals. But the road to health is not paved with Coke plus vitamins and minerals. This reductionistic attitude “is good for the food industry but not actually good for human health.” Why not? Well, if food is good only for a few nutrients, then you can get away with selling vitamin-fortified Twinkies.

We need to shift from the concept of merely getting adequate nutrition to getting optimal nutrition. That is, we shouldn’t just aim to avoid scurvy, but we should promote health and minimize our risk of developing degenerative diseases.

Bringing things down to their molecular components works for drug development, for example, discovering all the vitamins and curing deficiency diseases. In the field of nutrition, “[h]owever, the reductionist approach is beginning to reach its limits.” We discovered all the vitamins more than a half-century ago. When is the last time you heard of someone coming down with scurvy, pellagra, or kwashiorkor, the classic deficiency syndromes? What about the diseases of dietary excess: heart disease, diabetes, obesity, and hypertension? Ever heard of anyone with any of those? Of course we have. Yet we continue to have this deficiency mindset when it comes to nutrition.

When someone tries to reduce their consumption of meat, why is “where are you going to get your protein?” the first question they get asked, rather than “if you start eating like that, where are you going to get your heart disease?” The same deficiency mindset led to the emergence of a multibillion-dollar supplement industry. What about a daily multivitamin just “as ‘insurance’ against nutrient deficiency?” Better insurance would be just to eat healthy food.


Professor Emeritus T. Colin Campbell wrote a Whole book about this issue, and I’m looking forward to doing many more videos on the topic.

So, where do plant-eaters get protein? Check out Do Vegetarians Get Enough Protein? to learn more.

The concept of optimal, rather than merely adequate, nutrition is illustrated well in this video about fiber: Lose Two Pounds in One Sitting: Taking the Mioscenic Route.

Other videos on reductionism include

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: