Dietary Estrogens and Male Fertility

Image Credit: Taber Andrew Bain / Flickr. This image has been modified.

Dietary Estrogens & Male Fertility

In my video, The Role of Diet in Declining Sperm Counts, I discussed the association between high saturated fat intake and reduced semen quality. But what’s the connection? One of the most recent papers on the topic found that a significant percentage of the saturated fat intake in the study was derived from dairy products. Residues of industrial chemicals may bioaccumulate up the food chain into animal fat, and some of these lipophilic (fat-loving) chemicals may have hormone-disrupting abilities.

The U.S. Environmental Protection Agency performed a national survey of persistent, bioaccumulative, and toxic pollutants in the U.S. milk supply (highlighted in my video, Dairy Estrogen and Male Fertility). The EPA team noted that since milk fat is likely to be among the highest dietary sources of exposure to these pollutants, it’s important to understand the levels in the dairy supply. The team tested milk from all over the country and found a veritable witches brew of chemicals. They estimate that dairy products alone contribute about 30% to 50% of our dioxin exposure. And “like dioxin, other toxic pollutants tend to be widely dispersed in the environment, bioaccumulated through the food chain and ultimately result in low-level contamination in most animal fats.”

This may explain higher pollutant concentrations in fish eaters. Xenoestrogens like polychlorinated biphenyls (PCBs) are associated with the fats of fish or animal flesh and cannot be fully removed by washing and cooking, and so can accumulate in our fat, too. Xenoestrogens are chemicals with demasculinizing or feminizing effects. But even in a non-polluted world, animal foods also have actual estrogens, which are unavoidable constituents of animal products. All foodstuff of animal origin contains estradiol, which is at least 10,000-fold more potent than most xenoestrogens. Dietary exposure—meat, dairy products and eggs—to these natural sex steroids is therefore highly relevant, as the hormones in these animals are identical to our own.

Estrogens are present in meat and eggs, but the major sources are milk and other dairy products. By drinking a glass of milk, a child’s intake of estradiol is 4,000 times the intake of xenoestrogens in terms of hormone activity. Modern genetically-improved dairy cows can lactate throughout their pregnancy. The problem is that during pregnancy, estrogen levels can jump as much as 30-fold.

Cheese intake has specifically been associated with lower sperm concentration, whereas dairy food intake in general has been associated with abnormal sperm shape and movement. Lower sperm concentrations by themselves may just represent a potential suppression of sperm production due to higher estrogen levels, but abnormal shape and movement suggests that dairy intake may be implicated in actual direct testicular damage.

While milk products supply most of our ingested female sex steroids, eggs are a considerable source as well, contributing about as much as meat and fish. This could be expected, as eggs are produced directly in the hens’ ovaries.

Meat may also contain added hormones. In the U.S., anabolic sex steroids may be administered to animals for growth promotion, a practice banned in Europe twenty-five years ago. A study in New York found progressively lower sperm counts associated with processed meat consumption. However, similar studies in Europe after the ban found the same thing; so, it may not be the implanted hormones, but rather a consequence of other meat components, such as the saturated fat raising cholesterol levels.

We’ve known for decades that men with high cholesterol levels show abnormalities in their “spermiograms”: decreased sperm concentration, about a third of the normal sperm movement, and half the normal sperm shape. Twenty-five years later, we’re finding the same thing. In the largest study to date, higher blood cholesterol levels were associated with a significantly lower percentage of normal sperm. Cholesterol was also associated with reductions in semen volume and live sperm count. These results highlight the role of fats in the blood in male fertility, and should be of concern given the rising prevalence of obesity and cholesterol problems. Although a healthier diet may be associated with healthier sperm counts, cholesterol-lowering statin drugs do not seem to help.

What about the phytoestrogens in soy? See The Effect of Soy on Precocious Puberty.

More on hormones in dairy in:

Neurotoxic chemicals in the dairy supply have been blamed for neurological conditions as well. See my video Preventing Parkinson’s Disease with Diet.

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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.


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.

31 responses to “Dietary Estrogens & Male Fertility

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  1. Does all this apply to Whey protein? Is it just in the dairy fats, and not the proteins? Also, what about 100 percent organic grass-fed cheese, dairy, etc.? Same issues?

    1. Probably not but why consume whey protein anyway? Why whey you might say.
      “Among the different types of macronutrient restriction, reduced intake of proteins and amino acids is the most effective pro-longevity intervention 35, 36. Simply reducing protein intake can deliver an equally potent impact on lifespan as dietary restriction in multiple model organisms 35. A recent analysis of the National Health and Nutrition Examination Survey (NHANES) showed that low protein intake was associated with reduced overall mortality for those under 65 years of age 37. Also, a high-carbohydrate, low-protein diet resulted in longer lifespan and improved cardiometabolic health, despite increased food intake and body fat 38, 39”

        1. Ah, OK. I have not looked into this much but there was a monkey study some years ago which may throw some light on this. Interestingly, there was no effect in the first two months but
          “During the next 60 days of the investigation, sustainable plant and animal protein diets had differential effects on a number of sperm quality indices. When compared to the plant-based diet, the monkeys that were given the animal protein diet containing milk solids had lower sperm counts (p < .04), reduced sperm motility (p = .04), higher sperm midpiece abnormalities (p < .05), and a trend (p = .10) towards increased sperm head defects."

  2. I have so many questions about estrogen. Men’s own bodies make estrogen too, right? How much more estrogen does a woman make than a a man, three times, 10 times? I mean naturally, excluding the dietary estrogens, and xenoestrogens.. They give transexuals estrogen so that they can transition, grow breasts, etc, right? So how many times more than a man’s natural estrogen level does it take. Do they riaise the man’s estrogen levels to that of a woman, or does it take more to counteract his natural testosterone? Now how much dietary estorgen does an average American take in, what percentage of his circulating estrogen is natural and what percent is dietary?

    1. Then there is this:

      Stanford University researchers Ben Dulken and Anne Brunet argue that it’s time to look at differences in regenerative decline between men and women. This line of research could open up new explanations for how the sex hormones estrogen and testosterone, or other factors, modify lifespan.

      It’s known that estrogen has direct effects on stem cell populations in female mice, from increasing the number of blood stem cells (which is very helpful during pregnancy) to enhancing the regenerative capacity of brain stem cells at the height of estrus. Whether these changes have a direct impact on lifespan is what’s yet to be explored. Recent studies have already found that estrogen supplements increase the lifespan of male mice, and that human eunuchs live about 14 years longer than non-castrated males.

      So if you are male…maybe driving your estrodial levels down might not be the best move?

      I recently stopped most if not all dairy/eggs…making my own salad dressings not involving milk products. This is partially due to the casein in milk interfering with the phyto-chemicals in plant foods.

      Instead of ice cream…I much on frozen strawberries/blueberries.

      After stopping most meat except for wild-caught salmon….when visiting relatives that still focus meals around meat…I notice that the chicken that is cooking stinks to high heaven…the pulled pork they eat is pretty raunchy.

      I do take some supplements that include amino acids…assuming that I’m missing some of the xenoestrogens and so forth in meat.

  3. Great blog entry! These seem like points to raise when confronted with the new “saturated fat and cholesterol are good for you” argument.

  4. Although I agree that dioxins are are toxic, likely carcinogen and interfere with hormones, the number for milk fat being 30% of exposure is contradicted by your reference’s abstract and discussion. Dioxin levels are dropping since the 80’s and likely a bit more as the general chemicals have been banned although they are still produced as byproducts in other industries. From the abstract it’s closer to 15% for adults, not sure what it is for children as it’s not stated further but might be higher as the average child probably drinks more milk. I’m not sure if the overall exposure to dioxins (the 55pg/l) has decreased as the article is not clear on that point.

    “Average adult daily intakes from total milk fat ingestion were computed for all detected compounds and compared to total intakes from all pathways: CDD/CDF/PCB TEQs: 8 vs. 55 pg/day…”

    “This study found CDD/CDF/PCB TEQ levels in milk to be about 50% lower than those reported in a similar study conducted in 1996 Lorber et al., 1998). If this difference is truly indicative of declining milk levels and assuming exposure levels from nondairy pathways have remained the same over this time period, this would result in an overall decrease in adult background CDD/CDF/PCB TEQ exposure of 15%. Several factors could account for these apparent changes in dioxin levels in milk including uncertainties in the approach as discussed earlier, reduced emissions, and changes in agricultural practices.”

  5. I have a question: If the above were indeed the case, how bodybuilders who are consumers of copious amounts of eggs and dairy are not getting effeminated – quite the opposite is observed in fact.

    1. Body builders do look bigger and stronger, but their sperm count and sex drive is often reported to be lower. That’s even without taking anabolic steroids.

    2. Modern body builders are getting bigger bellies – you don’t see the slim waist line that Arnie had any more. The pregnant belly on someone with paper thin skin has been put down to using excess growth hormone – I wonder if whey protein concentrate stimulates IGF-1 and causes the excessive intestinal growth as well?(since many who swear they don’t take GH still have the big belly). I have a body builder friend who ingests enormous quantities of whey protein, olive oil, supplements, injects peptides, and eats small amounts of broccoli and beef (heard him say once about his protein powder, coffee and coconut oil shake – I don’t have to eat food – it keeps me full!). A look in his medicine chest reveals several blood pressure medications, cholesterol lowering pills, erectile dysfunction pills, and so much more its scary. Yet he has well defined abs on his big belly, and no fat under his skin at all. He believes he is healthy and in better shape than me (since I’m a little plump) and that I will go to hell on my low protein diet! (I’m 58 and my blood pressure is 105/70 and I don’t take anything except a monthly B12).This belief that protein is a god and can do no harm is a big worry…….

  6. Organic milk is the only animal product I consume. I use it only to make kefir. Usually, a couple of cups a day. I’M 63, athletic and lean. The above research is making me question if I should continue making/consuming kefir. What do you think?

    1. I am a French medical doctor, I was used to have home made Kefir in my family since I was born, my grand mother was making a kefir drink without milk but dried fruits and citrus. Here in the US I stopped to get any dairies , no milk at all , I stopped kefir and yogurt . since I banned all milk, goat sheep cow, all organics, I am better. I stopped to try to know what is in the milk in this country I just change my diet: dairy free gluten free no sugar , no salt added. all organic. I am old, no treatment and same size 4 as in my 20s . I can walk 3 miles a day when I am not too busy.

      1. Coconut milk may be less healthy than cow’s milk; it is one of the rare plant sources with a lot of saturated fat, which probably means it is not a good idea for daily use. But of course there’s no cholesterol in coconut milk.

        There are plenty of cultures that will work on anything with sugars though, and turn it into something sour (lactobacilli, acetobacter) or alcoholic (yeasts). A good read on the topic is Wild Fermentation, though that focusses on ferments with wild/airborne rather than explicitly added cultures.

        In general, I found that the opinions on ferments vary drastically on this site. Taste and personal experience seems to play a large role in that :)

        1. vanrein: Coconut milk does have a lot of saturated fat, but does that make it worse than dairy? Coconut milk would not only be missing the cholesterol, but also the contaminants typically found in dairy, the hormones, and the animal protein. Also, coconut milk would not have the puss. (Even if puss isn’t a health issue, I just have to mention it. Because, ewww.)
          Thanks for your post, though. It’s great that you mentioned that cultures can work on other liquids. I was using coconut milk as an example because people love it (it seems like a good transition liquid for someone used to dairy milk) and it was the first recipe I found to provide as an example. Another poster mentioned that he knows someone who uses soy milk as the liquid. Given all the benefits of soy (that are explained on this site), I would guess that soy kefir would be especially healthy compared to other kefir options.
          Also, thanks for the book recommendation. Looks great!

    2. I’m not sure why organic milk should be any lower in dioxins that any other milk. Dioxins are ingested by the animals from the grass or grain. Dioxins are the result of human activity, burning trash, forest fires, industrial pollution. Organically fed cows are not protected from these airborne chemicals that deposit on the soil, plants and waters.

  7. The French Food regulation started in the 60s to forbid hormone to feed chicken because the medical survey observed male new diseases with these new chicken on the market. When I worked in Urology for cancers ED and infertility , 20 years later, we prescribed with also asking to stop all dairies, eggs and chicken except raw cheeses. Most of the time after 2-3 months we had excellent results. I have seen microvascular cysts in the bowls , improved after diet and we were doing lighter surgery after a serious diet. Here in the US I have seen children reducing their breast, when stopping to eat conventional eggs chicken and dairies. I am French so I am used to prescrive a different diet with gender.

    1. Thank you for your question,Cesar. I’m glad you are monitoring your estrogen level and now that you know it is “very high” you certainly want to do what you can control it. Fortunately, diet is under your control and considering the research on meat and poultry, even organic, you may make the decision to reduce exposure by eliminating those foods. There are several videos on that will help provide the motivation you need to replace meat and poultry with better choices If you search “estrogens and males” Organic may reduce but still allow hormone exposure and alas as points out even if estrogen levels are lowered, there are other health concerns with meat and poultry which switching to organic will not resolve. It sounds giving up meat and poultry will be difficult for you. Have you tried non-animal alternatives? More and more products are available that you may find not only tasty but healthy, if they aren’t overly processed (seitan, tempeh, etc).

  8. Why when I went to the doctor a year ago , he handed me some health recommendations type pamphlets clearly recommending increasing milk consumption?

    1. Thanks for your comment Esben!

      While there a number of reasons why your doctor may have made that recommendations, the great majority of doctors get little to no training in nutrition and even if they do, it is possible that they are simply unaware of such information has they have multiple things to worry about & this is why is such a great tool to keep you well informed – thanks to Dr Gregers & the whole NF staffs work.

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