Doctor's Note

Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on dairy. Also, there are 1,686 other subjects covered in the rest of my videos--please feel free to explore them as well!

Please also check out my associated blog posts for some more context: Mad Cow California: Is the Milk Supply Safe?, Breast Cancer and DietCow's Milk Casomorphin, Crib Death, and AutismStool Size and Breast Cancer Risk,  Protecting Our Babies From PollutantsWhy Are Children Starting Puberty Earlier?, and Avoiding Dairy to Prevent Parkinson's

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  • Eric Needs

    great research

  • sagefemme

    Dr. Greger, are there studies about early puberty and non-milk dairy (yogurt, cheese, etc)? I assume there would be as much bovine endocrine debris in these products as the milk they were made from, but do we know?

    • Michael Greger M.D.

      The study showing the connection between premature puberty and animal protein consumption in general did indeed include all dairy items. More at http://nutritionfacts.org/topics/puberty/

  • beedub8

    Hi Dr. Greger – My husband has prostate cancer and after two unsuccessful surgeries (brachytherapy and cryosurgery) he is now being given hormone treatments in a drug called Lupron. If prostate cancer is an estrogen-dependent disease, as you state in this video, why would the docs be feeding it to him to slow down the cancer growth?

    Here’s a partial definition of estrogen in the American Heritage Dictionary: “. . . substances that. . . are used to . . . ameliorate cancers of the breast and prostate.”

    What am I missing?

    Thank you so much for the excellent work you do!

  • psiscobr
  • Vallis

    Many people probably saw the story about Jeremy Pevin the actor where he said:

    (snipped)

    “…”I was the guy that dabbled in soy milk, but now I’ve found out soy milk has enough estrogen for me to grow breasts,” he told STV (via Digital Spy). “I had to put the soy milk down. It was a very confusing time.”

    Turns out Piven was drinking 12 cups of soy milk a day! ….”

    Is it 100% conclusive that soy does not have unwanted estrogen for men? I have heard from more than one source that it was not good to drink too much of it if you are a guy.

    I do not drink regular cow’s milk (for decades) either and have switched to almond milk. I could not find any commentary on almond milk on this website.

    Perhaps you could direct me to a place where almond milk is mentioned on the site , if it is.

    • YoungNHealthy

      I can’t answer your exact question but would just like to state that no matter how healthy anything is for you everything must be taken in moderation even moderation. (I.E. If you drink too much water at a time you can wind up drowning your liver and killing yourself.)

  • Lizzette Jimenez

    Is there any difference in the levels between a grass fed, pasture raised cow and that from a cow in a “Factory Farm” or “CAFO”? 

    • Toxins

       The only difference may be in contamination level but this is not the issue here. What this video is looking at is the nutritional composition of milk itself which is relatively unchanged whether it be organic or conventional. Milk is indeed used to grow a baby calf and this is a completely unnatural substance for adult humans to be consuming.

  • Michael Greger M.D.
  • Michael Greger M.D.

    Please also check out my associated blog post, Mad Cow California: Is the Milk Supply Safe?!

  • Kerem Avital

    Thank you for this interesting video (as usual) ,I’m a vegan dietitian and I have 2 question about this topic:
    1. I can’t remember where I read it, but I think that the half life of Estrogen is only 50 hours, I’m not sure if that’s correct and I also don’t know to what exactly does this Estrogen break up to… do you know about any research that deal with this question?
    2. About soy, I know that soy have a protective effect from Estrogen related cancer. But I’m not sure that this is the same with sexual development. most of the researches I found had been focus on infant formulas. And they found that soy formulas may also precede sexual development. I also found a research that claim that high Isoflavone in the serum may be connected to early puberty:
    http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2265.2011.04127.x/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=falseWhat's your opinion about this subject?
    Sorry in advance for my bad grammar… (I’m from Israel)

  • Toxins

    jojo, the article is obsessed with phytic acid, when all beans, not just soy, and many grains contain phytic acid. Phytic acid is neutralized by cooking, and I do not know many people who eat raw beans. Trypsin is also deactivated with cooking. Soy does not affect hormonal levels either as shown by this video. Nitrosamines are forms not from high temperature cooking but when nitrites are exposed to fat. Nitrates and ntirites are different substances. Nitrates are found in plant products.
    http://nutritionfacts.org/video/when-nitrites-go-bad/

    The article is filled with flawed information.

    • Kathryn McMorrow

      What about eating raw legume sprouts? Is the phytic acid diminished at all through germination?

  • rob

    Does this also apply to fermented milk such as yogurt and kefir?

  • Skeptic

    This is one of the most helpful websites I’ve ever seen. I’ve been studying it for several months now and even down loading some of the journal articles it references. I feel so much better informed and able to take care of my family members better! Great work!

    • Thea

      Welcome aboard Skeptic. I agree that is feels great to be informed and self-empowered. This is a great site.

      Thanks for posting.

  • Elisabeth

    I’ve searched the (excellent and helpful) site for information about uterine/endometrial cancer but haven’t found much. Is there a lack of research to report? I’d love to be able to find more information.

    • Tommasina

      Elisabeth, is there something specific about uterine cancer that you’re looking for? I’ll see if I can help. :)

  • Rachel Cummings

    Hello Dr. Gregor, there’s a history of uterine cancer in my family, my grandma and her sister both had it and my aunt had it. My mom is paranoid about soy foods and thinks that they cause cancer and since I became vegan is hyper aware of my soy intake. I was curious about what you’ve found out about soy intake and uterine cancer. Is it something I should be worried about or is it actually good to have soy like it is for breast cancer?

    • Thea

      Rachel: This website has a *bunch* of information about traditional soy products and cancer. Usually the videos discuss soy vs breast and prostate cancer. But I would think (though I’m no doctor or expert) that the same information would be applicable to uterine cancer.

      I highly recommend checking out the videos and articles in the link below. But I’ll give the bottom line summary here: 2-3 servings a day of traditional soy products like tofu, tempeh, and soy milk are healthy foods that likely help prevent cancer and/or help prevent cancer recurrence. It’s most likely to provide preventative benefits for women if you eat it your whole life, but I still think there are studies Dr. Greger highlighted that show benefits at any age. I certainly do not see how it could hurt you or your family.

      HOWEVER, note that “isolated soy protein” which comes in many processed packaged foods, does *not* count as a traditional soy product. And note that many commenters have posted on this site that isolated soy protein may be as bad for you as dairy in terms of how it affects IGF-1 (another NutritionFacts video I highly recommend).

      I’ll also add that some people think that it is important to get organic soy. That way you avoid pesticides and the GMOs. (Other people think that GMOs are not a concern.) Luckily it is easy to get organic soy products – or at least those labeled as GMO-free.

      http://nutritionfacts.org/index.php?s=soy

      Hope that helps.

    • http://www.DonForresterMD.com/ Don Forrester MD

      There are many factors associated with increased uterine cancer as Dr. Greger points out estrogen intake is one factor. Obesity and diabetes are also associated with uterine cancer… I’m assuming you speak of uterine cancer and not cervical cancer which has other associated risk factors. Overweight and obese women are at more risk for uterine cancer… hard to say if it is from the foods such as dairy or from the estrogen that is produced by fat cells. As Thea points out whole soy products are fine. Good luck.