Estrogen in Meat, Dairy, and Eggs

Image Credit: Nakhorn Yuangkratoke © This image has been modified.

Estrogen in Animal Products

Estrogen hormones can be thousands of times more estrogenic than typical endocrine-disrupting chemicals. Dietary exposure to natural sex steroids (in meat, dairy, and eggs) is “therefore highly relevant in the discussion of the impact of estrogens on human development and health.” And chicken estrogen is identical to human estrogen—they’re the same molecule. So, it doesn’t matter if it ends up in our drinking supply from women taking birth control pills excreting it in their urine, or cows excreting it into their milk. The source doesn’t matter; the quantity does.

If you check out my video Estrogen in Meat, Dairy, and Eggs, you can see that a child’s exposure to estrogens in drinking water is about 150 times lower than exposure from cow’s milk; so, our day-to-day estrogen exposure levels are more likely determined by whether or not we happen to eat dairy products that day.

Human urine is “often cited as the main source of natural and synthetic estrogens in the aquatic environment,” but the level of estrogen even in the urine of heavy meat-eaters, who have significantly higher levels, pales in comparison to the estrogen excreted by the farm animals themselves. Pigs, sheep, cattle, and chickens produce literally tons of estrogen every year.

Women may excrete 16 mg every day, but farm animals may release ten times more, or in the case of pregnant cows, thousands of times more. Animal waste may contribute an estimated 90% of total estrogens in the environment. Five gallons of runoff water contaminated with chicken manure may contain a birth control pill’s worth of estrogen.

Estrogen levels in poultry litter are so high that when farmers feed chicken manure to their animals to save on feed costs, it may trigger premature development. Poultry manure has among the highest hormone content, quadruple the total estrogens, and nine times more 17-beta estradiol, the most potent estrogen and a “complete” carcinogen, as it exerts both tumor initiating and tumor promoting effects.

From a human health standpoint, do we really care about feminized fish, or the appearance of “intersex roaches”? The problem is that the hormones get into the food supply. Endogenous steroid hormones in food of animal origin are unavoidable as they occur naturally in these products. It’s not a matter of injected hormones, which are banned in places like Europe in order to protect consumers’ health. Sex steroid hormones are part of animal metabolism; and so, all foodstuffs of animal origin contain these hormones, which have been connected with several human health problems. (See Why Do Vegan Women Have 5x Fewer Twins?)

What effects might these female hormones have on men? See Dairy Estrogen and Male Fertility.

The implications of this relatively new practice of milking cows even when they’re pregnant is further explored in:

More on xenoestrogens in:

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—2013: Uprooting the Leading Causes of DeathMore Than an Apple a Day2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

Image Credit: BruceBlaus


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.

68 responses to “Estrogen in Animal Products

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    1. Really? It makes so much sense. People will let me know that me eating soy beans is a concern because of the plant hormones. When I respond that eating meat or drinking milk contains hormones obviously they can’t even argue with that. Animals contain hormones. Not even considering the added hormones these animals consume.

      1. I mean.. not only that but about the complexity of the issue, the enviroment, animals getting transformed because of it. you know.. sometimes the reality seems crazier than conspiracy theories!

        1. Have you seen Cowspiracy? A must see. The general population just doesn’t know this stuff. I think that if they did it would be more mainstream and change can/will happen. I feel we are almost at that tipping point. But….I am the eternal optimist!

          1. Yeap Im aware of this things really but I feel most people only care about tv shows, eating, booze and everyday life. Really hard to have a complex conversation and when you do, good things can happen: 1) they get offended or 2) you are the crazy one or 3) they are already diluded into other even crazier ideas!

            1. I try to keep a positive outlook, and for the most part I do, but yes, I completely agree with what you are saying, and I’ve had the same responses. These are largely interactions with my family which is more upsetting because some are obese and in very poor health and they just don’t care. But I do, and I can’t just dismiss them as I would a stranger.

    2. It can be lonely. I wish I could carry around stacks of “How Not to Die” and hand them out when people start talking. Last week I had a close friend tell me that everything I believed about food was just a bunch of bull. She was so nasty and condescending. This from a person taking meds for her diabetes and hypertension. It’s just so sad.

      But when you hear what the professionals have to say about animal products, aren’t you glad that you’;re not eating the poison. Every day I look at all of the people carrying around the layers of fat on their bodies from all the junk they consume and I feel so sorry for what we are allowing to happen to ourselves and our planet.

      1. brrr because we are social beings, sometimes I feel so lonely thinking I have no one to talk to about the REAL THINGS. I feel like Im in a kind of show that I have to act oblivious to this things that are so important to me and have to do the everyday stupid talk and I put on a show of a different person than who I really am. Gets me crazy really!

        1. Alexandre: I’m totally following what you are saying. You are probably already aware of this, but just in case it would be helpful: You can’t easily dump your family, work or existing friends and probably don’t want to. But you can add to your social circle and get some support by joining groups who already “get” WFPB diets. It is wonderful moral support. If you are not already familiar with the the site, I recommend it as you can use it to find vegetarian and vegan groups in specific areas. You might also ask at local

          Also, some people find that checking in here on the forum and making the occasional comment to be helpful/makes them not feel so alone. :-)

          1. Thea: “Also, some people find that checking in here on the forum and making the
            occasional comment to be helpful/makes them not feel so alone. :-)”

            Ditto to that comment!

            1. Yes, in many ways I feel this group of regular commenters is my tribe. Compared with people who comment on other blogs and web videos, people here are so much better educated, curious, and intelligent. We all have our differences, as in any tribe or group, but there is a core of understanding about many important things, especially diet, that we share.

              My old friends are kind and put up with me, lovingly, but they don’t subscribe to my notions and usually aren’t interested in learning more. But when they have a friend with cancer they often refer her or him to me to learn what they can do to get through the ordeal as best they can.

              I live in a smaller city, without any vegetarian restaurants, but there are meetup groups here which I’ve been thinking about looking into. It would be nice to have an understanding group locally.

              1. “Compared with people who comment on other blogs and web videos, people here are so much better educated, curious, and intelligent.”

                And don’t forget, better looking, to too. ;-)

    3. The problem is that the majority of people hate change and will fight it tooth and nail. Most people think that they are eating a healthy diet, but for the most part appear to driven more by pleasure than health.This is why it is so easy for food companies to “health-wash” what ever hyper-palatable, pleasure optimized crap they are selling. By discussing actual nutrition with them, especially as it relates to the unhealthfulness of animal products, you are holding a mirror up and they are uncomfortable with what their reflection says about the healthfulness of their diet. They know that if they accept what you are saying and if they really do care about their health they will have to change their diet. Change, even good change, is stressful. The natural defense mechanism is deflection and so you become the one that has a problem and they are the normal ones. That allows them to discount what you are saying and continue deluding themselves about how healthy their diet is.

      1. Which is probably also why even doctors who have heard about the benefits of WFPB aren’t informing their patients…practicing what you preach and all that…so just ignore it. Talk about an uphill battle.

    1. There are a lot of videos on the subject here. If you haven’t already searched for the topic you should. Here is one on soy and breast cancer.

      One thing I do remember is that it is a good idea to try to consume organic soy because by doing so you avoid the consumption of GMO soy which has been found to have some problems. I must admit I do sneak into the Tofu House in Albuquerque to order a fried tofu sandwich every once in a while, it probably isn’t made from organic beans, but oh my fresh tofu is yummy!

      1. In the past, I was told that beans suitable for tofu or tempeh haven’t been engineered, just what’s grown as animal feed.
        Maize is a bit more complex than that.

    2. There are two estrogen receptors in humans, alpha and beta. Animal estrogen preferentially binds to alpha and soy phytoestrogens preferentially binds to beta. When estrogen binds to alpha it stimulates cell proliferation and when it binds to beta it suppresses proliferation. Also it is my understanding that when an estrogenic molecule is bound to either receptor, it blocks estrogen binding to both alpha and beta. So this would indicate that soy phytoestrogens would suppress cancer proliferation by binding to the beta receptor and while doing so block any alpha binding estrogen. The observations that breast cancer rates are much lower in cultures that eat the most soy lends support to the idea that soy actually suppress breast cancer growth. In this video, Dr. Greger reviews a study of women with estrogen positve cancer that shows that consuming soy reduced their risk of dying from their cancer by 50%.

      But not all phytoestrogens bind to the beta receptor. Interestingly back in July Dr. Greger had a video on about the very potent phytoestrogen 8-PN in hops used to flavor/preserve beer that binds to the alpha receptor. And that is really sad because a study of post-menopausal women showed that hops had a very powerful and immediate effect on the rate of hot flashes. However as an alpha binding estrogen, hops would be expected to have the same cancer promoting effect as does hormone replacement therapy with animal estrogen. This is also definitely something to think about as one enjoys their double hopped imperial IPA.

      1. Jim, thank you for your clear explanation about alpha and beta receptors, etc. Somehow a lot of that had escaped me. And darn! I do like a good amber ale now and then!

        I suppose using hops tea to promote sleep is a bad idea, too.

    1. Use of manure imported from conventional farming operations is allowed. The FDA wants to limit the use of animal manure but the organic farmers are up in arms about it. Obviously those that are up in arms about the FDA are either ignorant or greedy!!!

  1. It is said that 1 out of 7 are addicted to dangerous drugs but 67% are addicted to dangerous foods. Guess which one the government is spending great amounts of resources to change?

  2. I read things like this related the our eating habits and think of how many people rely on their Dr. for health advise and then read that one of the most prestigious medical schools in the country, Harvard Medical School, is discontinuing all nutrition classes. AMAZING!

    Colorado Gene

    1. J: I believe it does. I think quote shows that the information applies as much to Canada as the USA (just substitute “Canada” where you see Europe mentioned):

      “It’s not a matter of injected hormones, which are banned in places like Europe in order to protect consumers’ health. Sex steroid hormones are part of animal metabolism, and so all foodstuffs of animal origin contain these hormones, which have been connected with several human health problems. (See Why Do Vegan Women Have 5x Fewer Twins?)”

        1. WFPBRunner: Very sad to hear about the sister.

          Thanks for sharing though. I think some of the laws in say Canada and Europe which are enacted to provide some protection to people (ex: no added hormones to the animals) have had the disadvantage of providing a false sense of security/safety in the people. This is the second time in a very short time someone has asked if a problem applies to Canada too. It is an understandable question. I just think the question points to an underlying problem those countries will have to address.

          Or put another way: In some way, the USA disaster of a system is an advantage, because it is easier for people to see how much of a mess our food supply is in.

  3. I eat no meat, dairy, or eggs. I eat a lot of produce from my garden, so I assume that I am not getting any estrogen from what I eat. My water comes from an underground aquifer, so I guess it is free of estrogen. However, I am wondering if it possible to get estrogen in the air that we breathe.

    1. Interesting question. The amount of estrogens in dairy cow manure (since dairy cows are not kept nearly continuously pregnant) and especially chicken manure could be such that you might not want to breath a lot of it when it dries out and gets blown about by the wind. As such people who work in dairy and chick CAFOs might be breathing enough poo dust to be an issue. Even people who live downwind of such facilities could be breathing in enough poo dust to be an issue. Probably worth testing if nothing else. Even smallish amounts for long enough period of time could make a difference.

  4. Clearly shows the wisdom of avoiding animal based proteins as meat or milk products and the superiority of vegan diets as eaten by healthy Chinese peasants according to the largest ever epidemiological study in The China Study by Campbell. Similarly cardiologist Esselstyn effectively used a vegan diet and lifestyle changes to reverse advanced heart failure in numerous terminal cases. Literally food for thought and better health!

  5. Is Dr Greger message getting to the last mile? Almost every video now talks about the same old stuff, either animal food is harmful or we should eat whole food plant based, things that we already know. Long gone is how to eat or cook cruciferous vegetables to get the max benefits, or the benefits of certain nuts, seeds, vegetables, legumes. etc. Dr Greger needs to bring more life and excitement to his videos.

    1. I find it strange the way you put this..not a regular reader here but i seem to understand that the purpose of this website is to put forth all the facts proving that a
      a whole plant-based diet is the best for human health..i guess it is a cycle depending on his area of research but for now he has not come up or is not focused on the plant-based receipes you are talking about..

      1. stefan seya: You wrote, “…i seem to understand that the purpose of this website is to put forth all the facts proving that a a whole plant-based diet is the best for human health.” I personally disagree with this sentiment. From my perspective, this site is about explaining what the body of scientific evidence shows regarding what is the best diet for the general population.

        It just so happens that the answer right now is a Whole Food Plant Base (WFPB) diet. But NutritionFacts is not trying to “prove” WFBP is best. NutritionFacts is just showing what proof we already have backing WFPB diets over other diets.

        It may seem like a small distinction, but I think it is an important one.

    2. I love this site, the community, its great staff, and of course Dr. Greger! I do have to agree with you Broccoli though that there hasn’t been a lot of new material lately. A lot of the videos and blogs seem to be repeats of research Dr. Greger has already covered.

      Did a quick change to compensate for autocorrect.

  6. Hello to all,
    I am very much in agreement with the WPBF diet but in the meantime when you check articulate and very reknown websites like Mercola, Josh Axe, Dr Jockers etc..they all include animal protein in their regimen plus they look very much healthy themselves..if anyone has an explanation regarding this paradigm please let me know!!

    1. Thanks for your comment Stefan.

      I think appearances are not the best tool to judge someones diet. For example, competitive bodybuilders have the best body, yet according to this publication they have 34% higher chance of dying than a sedentary McDonalds eating overweight/obese standard American male.

      And the other point is, we can not take data from single individuals and apply to the rest of the world. That is why we have epidemiological evidence that analyses the broad populations. And in here, as well as RCT and mechanistic data, everything point towards plant based diets being optimal for health. That is something that no one can deny because these are facts acknowledged by majority of health authorities in the world. The other thing is whether their personal eating habits leads them to cherry pick and ignore research that suits their cause but that’s a whole different topic – with all the respect to them.

      Hope this answer helps.

  7. In the first paragraph, I think the phrase ‘cows excreting it in their milk’ was meant to read ‘cows secreting it in their milk’. Cows excreting anything into their milk would be a whole other problem!

  8. This is one of my favorite pieces you’ve written because I’m so frustrated by the irony that non-vegs get up in arms about phytoestrogens in soy when true estrogens in meat are orders of magnitude worse for consumption. I’m part of a women’s healthcare startup and we commissioned an in-depth articled by two notable registered dietitians to address this topic. The title of the article ended up being “Phytoestrogens—friend, not foe”, from which you can infer the conclusion!

  9. Hope I was of help Stefan. I think regardless of what diet one may follow, encouraging exercise, not smoking and not drinking alcohol are always good things to encourage. Dr Greger talks about the dangers of animal protein extensively in this summary. I highly recommend you to read and explore the topics linked on there, it will give you a different perspective on animal protein that not may professionals know about or choose to ignore.

  10. This is a deceptive analysis.

    Distinction is not made between Organic pasture raised (no hormone added) animal products vs Factory farmed, GMO fed, hormone added animal products.

    There is negligible amount of estrogen hormone in organic milk where the cow is not subject to synthetic hormone injection. In fact there is a 100x more estrogen (considering Phyto-estrogen is 1000x less potent than animal estrogen) in Soy than Cow’s milk.

    How do you like it, if some one did an analysis on Vegetables without making a distinction between Organically grown vegetables vs Industrialized GMO farmed vegetables?

    1. That chart only measures phytoestrogens which are by definition plant-derived estrogens, so naturally they will be more prominent in plant foods. The only phytoestrogens in animal foods likely come from the plants in their diet. You are correct that there is a huge difference between grain-fed and/or GMO-fed cattle and grass fed or organic cattle and a distinction should be made. What is important though is that most of the animal products you buy in stores are not organic or grass-fed, so farmers most likely use synthetic hormones and practices such as feeding chicken feces to their cattle. Eating animal products with added estrogen from birth could cause unwanted side effects so consumers should be aware of the source of their food.

  11. Animals on natural grass based drug free, not grain based drugged diets would be the preferred study. The CAFO’s have so adulterated what it means to raise a healthy animal for decades that is impossible to find anyone in a civilized country that wasn’t or isn’t impacted negatively by their practices. Feminized fish is a big deal and you can’t blame it on chicken manure runoff when in fact the Puget Sound study certainly has no chicken manure in it. Hormone disruptors such as BPA and birth control pills are causes the scientists found. The huge amount of toxic chemicals we use yearly is the issue and the fact it only takes a tiny infinitesimal amount of a substance to change the body chemistry. If chemicals such as BPA and birth control pill runoff in the water supply at small doses can have that much of an effect(obviously since we re-ingest it), I doubt anyone eating a clean diet has anything to fear from animal products raised properly without garbage.

  12. Dietary estrogen quantities are on the order of 1/10000th of endogenously produced estrogen. In adults, does that really make a difference?

  13. Julie,

    There is no single easy answer as there is a ton of conflicting data, most of which is relative to which of the hormone replacement regimens your discussing.There is a significant difference between the various synthetics, which clearly do have a higher level of concern vs so called bio-identical hormone regimens and there are many options for both.

    In my experience, there appears to be a much safer and potentially beneficial effect from use of the bioidentical hormone therapies. After using the compounded bio-identical therapeutics with my patients for ~35+ yrs I have seen a decrease in expected CV disease and no increase in cancers among this population. Life satisfaction is enhanced and frequently reported for many, both in terms of cognitive function, sexual health and tissue integrity. Please keep in mind that these patients typically also have other lifestyle interventions taking place.

    Also keep in mind that there is a substantial difference between the available prescription vs compounded hormone products. This includes both price and delivery methods along with excipients and there’s plenty more to consider.

    Read about many of the options and see your health care provider as there is no single answer and any hormone replacement should be individualized. When you test your hormones, which should be one of the first steps, you might consider that there is good data suggesting that you use urine or salivary sampling, not blood.

    Dr. Alan Kadish moderator for Dr. Greger

  14. You realize that plants have a much higher content of these estrogenic horomones than animals do? Soy. Horrible. Maybe you should include this in your article. Also, no one feeds chicken shit to their animals. Ludacris.

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