The Most Potent Phytoestrogen is in Beer

Image Credit: Quinn Dombrowski / Flickr. This image has been modified.

Beer Phytoestrogens

Why do alcoholic men develop so-called man boobs and other feminine traits? We know estrogens produce feminization, and our liver clears estrogens from the body. As such, the original theory was that alcohol-induced liver damage led to the retention of excess estrogens. The problem was that when researchers measured estrogen levels, they weren’t elevated. What’s more, even those with cirrhosis of the liver appeared to clear estrogens from the body normally, and men’s testicles started shrinking even before serious liver disease developed.

So, alternative explanations were considered. If it’s not due to estrogens produced endogenously, meaning within the body, maybe alcoholics are being exposed to “exogenous estrogenic substances from dietary sources”—perhaps from phytoestrogens in the plants that alcoholic beverages are made from. The discovery that plants could contain hormonal compounds was made back in 1951 by two Australian chemists charged with finding out the cause of an “epidemic of infertility in sheep that was ravaging their nation’s wool industry.” It took them ten years, but they finally figured out the cause: a compound called genistein, present in a type of clover, and the same phytoestrogen found in soybeans.

You can read about the dreaded clover disease on scare-mongering websites, but you’ll note they never talk about the difference in dose. To get as much as the sheep were getting from clover, you’d have to drink more than 1,000 cartons of soymilk a day or eat more than 8,000 soy burgers or about 800 pounds of tofu a day.

This is not to say you can’t overdo it. There are two case reports in the medical literature that describe feminizing effects associated with eating as few as 14 to 20 servings of soy foods a day. But at reasonable doses, or even considerably higher than the one or two servings a day Asian men eat, soy phytoestrogens do not exert feminizing effects on men.

So, back in 1951, we realized plant compounds could be estrogenic. Two German researchers realized that perhaps that’s why women who handle hops start menstruating, and, indeed, they found estrogenic activity in hops, which is the bittering agent used to make beer. They found trace amounts of the soy phytoestrogens, but in such tiny quantities that beer would not be expected to have an estrogenic effect. In 1999, however, a potent phytoestrogen called 8-prenylnaringenin was discovered in hops, which I discuss in my video The Most Potent Phytoestrogen Is in Beer. In fact, it’s the most potent phytoestrogen found to date, fifty times more potent than the genistein in soy, “provid[ing] an obvious explanation for the menstrual disturbances in female hop workers in the past.” Today, we have machines to pick our hops, so our only exposure is likely via beer consumption, but the levels in beer were found to be so low that they shouldn’t cause any concern.

Then in 2001, a study on a hops-containing “dietary supplement for breast enhancement” raised the concern that another phytoestrogen in hops called isoxanthohumol might be biotransformed by our liver into the more potent 8-PN, which would greatly augment the estrogenic effect of hops. This study was conducted on mice, though. Thankfully, a study using human estrogen receptors found no such liver transformation, so all seemed fine…until 2005. “[T] he liver is not the only transformation site inside the human body.” The human colon contains trillions of microorganisms with enormous metabolic potential. It’s like a whole separate organ within our body, with a hundred livers’ worth of metabolizing power. So, let’s effectively mix some beer with some poop and see what happens.

Indeed, up to a 90 percent conversion was achieved. Up to then, “the concentration of 8-PN in beer was considered too low to affect human health. However, these results show that the activity of the intestinal microbial community could more than 10-fold increase the exposure concentration.” This can explain why you can detect 8-PN in the urine of beer-drinkers for days: Their gut bacteria keep churning it out. Obviously, the amount of straight 8-PN in beer is not the only source of estrogen effects given this conversion. So, a decade ago, the question remained: Might drinking too much beer cause estrogenic effects and feminize men? See my video What Are the Effects of the Hops Phytoestrogen in Beer? for the update.

Other videos on phytoestrogen include:

What about GMO soy? See GMO Soy and Breast Cancer.

For menstrual health videos, 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:


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, 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.

23 responses to “Beer Phytoestrogens

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  1. As a hormone-positive breast cancer survivor taking tamoxifen and wanting to minimize cancer recurrence, should I avoid drinking beer?

  2. Another hidden endocrine disrupting chemical hidden in today’s beers is glyphosate containing weedkillers which are now sprayed on hops before harvesting. Glyphosate inhibits cytochromome P450 and deplete minerals such as zinc… which disrupting sex hormone metabolism …xenoestrogen dominance and microbiome disruption ….

    1. Yeah, same here.
      I suppose one should brew their own beer, and leave out the hops; maybe adding an herb for bitterness like heather.
      Supposedly if the hops are not included, then the government regulations state that it can’t be called beer.
      A new enterprise for someone to undertake for the future?

      1. Not a new enterprise really. Actually that is how beer always used to be made. Originally it was called ‘ale’ It only became ‘beer’ once hops bgan to be added to the brew in the Middle Ages

        Where I grew up in Liverpool, people still commonly referred to pubs as alehouses

        However the modern stuff called ale is usually just beer brewed using a warm fermentation processs

    1. I was thinking the same thing. This may be a another/safer? way to maintain some anti-aging estrogen in the post menopause woman!

      1. Amy and Lynn, alcoholic drinks are NOT a safe way to raise estrogen,
        All alcoholic drinks raise breast cancer risk. See my post in answer to Kerry.
        Much better is to consume some soy. Also Dr. Barnard article cited in Deb’s post has some suggestions,

  3. Maybe this explains the Pharaoh Akhenaten’s feminine appearance.
    He must have been a big beer drinker, having plenty of beer at his disposal, and the ultimate man cave.

  4. Wonder if something like a Bock beer or Ale could be less dangerous? I used to drink Bock beer and thought the darkness of the brew suggested it was healthier. Is there an anti-estrogen one could take when drinking beer?

    I do remember from my drinking days that there would be some who would become all gushy-best-friendsy and others would become belligerent at the drop of a hat. I think in the latter group the testosterone way outweighed the added estrogen. ‘-)

      1. Oh good… an expert. Let me pick your brain.

        The Bock Beer I drank was brewed by the Pearl Brewery in San Antonio and the ones I drank were brewed some 50+ years ago (yes, I studied bock beers for a number of years, but I’m no expert ‘-)

        I bought a six pack of Shiner Bock Beer 5 or 6 years ago (still haven’t drank one of them.) The Shiner Bock looks a lot clearer and lighter than the very heavy Pearl Bock of my youth. In fact, it was so heavy a couple of beers would last me the whole night (a fellow Bock drinker said it came from the “mother” in the bottom of the vat and that was why it was so heavy) while my friends would drink 4 or 5 of their Coors or whatever they could lay their hands on.

        I know you are a teacher but I’m assuming you weren’t born at the time I’m talking about (or else you would probably be retired, living in Mexico, drinking some of those Mexican beers that used horse piss for brewing water ‘-)

        So, if you know any retired Bock brewers personally or professionally, please ask them about Pearl Bock Beer and ascertain if it truly was the “mother” from the bottom of the vat? ‘-)

        1. still haven’t drank one of them
          for clarity, should have read: “still haven’t drank *even* one of them.”

    1. Hello T,

      I’m a family doctor and a volunteer for Dr. Greger on this website. You have a reasonable question, and I don’t have a definite answer for you. However, as Dr. Greger mentions above, soy consumption in moderation is associated with decreased rates of breast cancer and decreased menopausal symptoms in women, and I just don’t know of any studies that demonstrate any sort of health problems from moderate soy consumption. (See also the video Dr. G refers to, above):

      So, although it’s certainly possible (and even likely) that our gut bacteria metabolize phytoestrogens, there’s no evidence that those metabolites cause any problems.

      Dr. Jon
      Health Support Volunteer for

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