1. Dan Wilson

    Dan Wilson Senior Member

    The video shown below shows a doctor (yes, he is an actual M.D.) claiming that cow's milk should not be consumed by humans because it is downright harmful and directly linked to diseases like cancer. It has been rather popular and commonly shared on social medias in the past few months. Here, I'll address both of the main points made in this short video and show why he is wrong in giving out this kind of advice.

    Dr. Michael Klaper starts off the video by claiming that the purpose of cow's milk is to turn a small calf into a 400 lb (181 kg) cow and throughout the video repeats this as if it is strictly designed for calves and should not be consumed by humans. He is right that milk makes a calf grow as fast as possible but how does milk do this? Besides the fact that calves drink very large amounts of it (6-11 quarts, 1.5-2.75 gallons) per day, the contents of milk can also contribute to this growth. Milk is typically rich in nutrients including, as Dr. Kapler says, "hormones, lipids, protein, sodium, growth factors, [and] IGF." Lipids, protein, and sodium are nothing special to milk with each of these on average contributing about 3% (lipids), 3% (protein), and less than 1% (sodium) to milk's total weight. What really seems to be the problem, in Klaper's opinion, are the hormones (growth factors like IGF). Indeed, these growth factors do contribute to the calf's growth but Dr. Klaper is forgetting some basic biology here.

    1) Hormones and growth factors are proteins. These proteins can be destroyed in various ways both before and after consumption. Firstly, milk is pasteurized. The high temperatures these proteins see during the pasteurization process can cause denaturation and subsequent inactivation of the protein. Second, in order for insulin-like growth factor (IGF) or any growth factor to affect you it also has to survive being broken down into its constitutive amino acids during digestion which, like most proteins, they do not.

    1a) If you're wondering how these hormones can possibly affect calves when digestion renders most of them inactive, hormones typically play a role only very early in calf development when the intestinal tract is not fully mature and can allow things like hormones, growth factors, and antibodies to pass into the bloodstream (same with humans, but baby formula does not contain hormones or antibodies). Beyond that, milk's role in a calf's rapid growth is simply that it is a nutrient rich liquid that the calf consumes a very, very large amount of.

    2) As Dr. Klaper keeps saying, this is cow's milk. The hormones in cow's milk is for baby cows. Hormones made by cows for cows simply do not work on humans. In order for a hormone to perform some action on a cell, it must first bind to a receptor and trigger a series of signaling pathways within the cell. Human cell receptors, however, do not bind to bovine growth hormones. So even if some small fraction of the growth hormones consumed survived both pasteurization and digestion and made it into the bloodstream, they can't trigger signals in our cells. (EDIT: Some cow hormones can't trigger human cells but some can. See below for more.)

    The other notable claim that Dr. Klaper makes in this video is that milk consumption is somehow linked to breast lumps in women and "man boobs" in men. The best available data, however, supports the idea that dairy consumption does not increase anyone's risk for any kind of cancer.
    So am I saying everyone should drink milk? No. What I am saying is that arguments like the one made by Dr. Klaper have no basis whatsoever in science and should not be taken as real health advice or used to promote certain agendas. If you don't want to drink milk or consume dairy for your own ethical or personal reasons, that's perfectly fine but doing so will probably not kill or harm you in any way we can measure. It is wrong to say otherwise under the guise of a medical authority.
    Last edited: Dec 18, 2018
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  2. DrKlaper

    DrKlaper New Member


    Regarding your critique of my comments on dairy products in the film, Cowspiracy,

    “…arguments like the one made by Dr. Klaper have no basis whatsoever in science…”


    “Hormones made by cows for cows simply do not work on humans. In order for a hormone to perform some action on a cell, it must first bind to a receptor and trigger a series of signaling pathways within the cell. Human cell receptors, however, do not bind to bovine growth hormones. So even if some small fraction of the growth hormones consumed survived both pasteurization and digestion and made it into the bloodstream, they can't trigger signals in our cells."

    I can only assume you made such comments unaware of the following studies:

    (Most modern dairy cows are pregnant, so their elevated blood estrogens find their way into the milk.)

    Pediatr Int. 2010 Feb;52(1):33-8.
    Exposure to exogenous estrogen through intake of commercial milk produced from pregnant cows. Maruyama K1, Oshima T, Ohyama K. (1)

    In this study, 7 men, 5 women and 6 children were each given 2 cups of milk to drink and their urine collected every 15 minutes. Within 15 minutes, each of their urine samples showed alarming levels of estrone, estradiol, estriol, pregnanendiol, and progesterone. The testosterone levels in the boys and men plummeted.

    If, as you state, “Hormones made by cows for cows simply do not work on humans,” because "they can't trigger signals in our cells," then why did the testosterone levels fall?

    If, as you state, “Hormones made by cows for cows simply do not work on humans,” because "they can't trigger signals in our cells," then why would the researchers state, “The present data on men and children indicate that estrogens in milk were absorbed, and gonadotropin secretion was suppressed, followed by a decrease in testosterone secretion.”

    If bovine hormones have no effect in humans, why would the pediatrician researchers state in their conclusion that, “Sexual maturation of prepubertal children could be affected by the ordinary intake of cow milk.?

    Surely, you accept that estrogens from horses are active in human females - hence the multi-billion dollar drugs like Premarin, made from pregnant mares’ urine, that clearly exert estrogenic effects, which is why doctors prescribe them for women with menopausal symptoms. Why would you expect estrogens of bovine origin to be inert? Horse-produced estrogens can stimulate breast lumps and uterine fibroid growth - as clearly printed on the warning label of the pharmaceutical - why would you think that the cow-produced versions of the same estrogens would not?

    Indeed, the author of the above-cited reference in Dermatoendocrinololgy states in his conclusion:
    “The evidence assembled here suggests that dairy-sourced hormones, not being subject to any innate feedback inhibition, may be the source of the androgenic and mitogenic progestins that drive acne, prostate and breast cancer. This is the most promising unitary hypothesis available to explain the etiology of diverse diseases that blemish, scar, shorten and take the lives of millions.”
    You dismiss my concerns re: milk consumption and elevated levels of tumor-promoting IGF-1 levels - but milk consumption does, indeed, elevate IGF-1 levels, whether by some of the ingested hormone surviving digestion in the stomach and upper GI tract, or by the flood of amino acids in the milk protein inducing a surge of endogenous IGF-1 production by the liver. Either way, milk consumption drives up IGF-1 levels - a good thing if you’re a growing calf; not a good thing if you are an adult woman with a small breast cancer, a man with a strong family history of prostate cancer or someone with acne. (2)

    Sir, the fact is that a growing number of clinicians and nutrition scientists are reconsidering their traditional endorsement of cow’s milk products as desirable components of the human diet for sound scientific reasons. No matter what role dairy products may have played in human history, given the current methods of industrial dairy production - with common usage of antibiotics, pesticide-laced feed grains, cross-contamination with bovine leukemia viruses, etc., and growing recognition of dairy-associated health problems, from acne to ovarian (3) and prostate cancer (4) and chronic sinus congestion - recommendations for dairy-free diets are being made with ever-greater frequency.

    The truth is that we have no more need for the milk of a cow than we do the milk of a giraffe. In view of the dairy-associated health risks listed above, and given the cleaner, more ecologically-sustainable and nutritionally-benign, plant-based milk alternatives now available, defending the place of cow’s milk products in the human diet is becoming increasingly untenable.

    I felt your assertion that “arguments like the one made by Dr. Klaper have no basis whatsoever in science” was unfair and unfounded, given the sound scientific basis these concerns actually have.

    (2) Dermatoendocrinol. 2009 Jan-Feb; 1(1): 12–16. Acne, dairy and cancer: The 5α-P link
    F William (Bill) Danby

    Milk Intake, Circulating Levels of Insulin-Like Growth Factor-I, and Risk of Colorectal Cancer in Men
    Jing Ma Edward Giovannucci Michael Pollak June M. Chan J. Michael Gaziano Walter Willett Meir J. Stampfer

    JNCI: Journal of the National Cancer Institute, Volume 93, Issue 17, 5 September (This article definitively demonstrates that milk-drinking raises IGF-1 levels. Though the study shows lower rates of colorectal cancer in the dairy consumers, the question is the effect of the IGF-1 upon the undiagnosed breast cancer or prostate cancer, ignored by this study.)

    (3) Milk and lactose intakes and ovarian cancer risk in the Swedish Mammography Cohort
    Susanna C Larsson Leif Bergkvist Alicja Wolk
    The American Journal of Clinical Nutrition, Volume 80, Issue 5, 1 November 2004, Pages 1353–1357,


    (4) B C Melnik, S M John, P Carrera-Bastos, L Cordain. The impact of cow's milk-mediated mTORC1-signaling in the initiation and progression of prostate cancer. Nutr Metab (Lond) 2012 9(1):74.(4)
    Last edited by a moderator: Dec 2, 2018
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  3. Dan Wilson

    Dan Wilson Senior Member

    Hi Dr. Klaper, I'm glad you came here for a discussion. I'll address your points as best as I can.
    (See below about cow hormones stimulating human cells) The problem here is that a causative agent for the change in testosterone levels was not searched for in the Maruyama study you posted. In other words, the experiments don't demonstrate that cow hormones are causing the observed effects. This is especially complicated because they have no negative or positive controls in their study. It turns out that serum testosterone levels drop after consumption of a normal meal in healthy men. https://www.ncbi.nlm.nih.gov/pubmed/22524522
    Again, which experiment shows this to be the case?
    I find this hypothesis to be highly speculative. The authors did not present evidence to support this and there is no correlation between milk consumption and the onset of puberty.
    This is why I'm happy that you responded, truly I am, because what I wrote was not correct. Some animal hormones can stimulate human receptors, you are right and I will edit my post accordingly. However, I maintain that your specific warnings about dairy are not supported by science. In this point, the issue lies in demonstrating a causative effect between the amount of hormone in cow's milk and any negative physiological effects. In fact, if the 0.8-2.2 nanograms of estrogen present in cow's milk could cause significant physiological effects, we wouldn't need to prescribe medications (at concentrations of 0.3-2.5mg a day) to treat symptoms of menopause. https://www.ncbi.nlm.nih.gov/pubmed/22561023
    Some of your sources recognize this shortcoming. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2715202/
    Meta-analyses of the literature conclude that there is no concrete association between ovarian cancer and dairy consumption. https://www.ncbi.nlm.nih.gov/pubmed/28665326
    I agree that we don't need milk in our diets.
    Would you warn patients about consuming too much estrogen from soy milk?
    I take issue with warning patients that they are putting themselves at risk of so many diseases from consuming milk and dairy when the science does not support such ideas. Epidemiological studies have failed to reveal a link between milk consumption and diseases like cancer and even obesity. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3267168/
    It is irresponsible to advise patients that they should never drink milk while citing the information you have given here because science does not support it. Science does support the idea that dairy can be more harmful to subpopulations of people but not everyone, and it probably won't be the causative agent of your cancer.
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  4. Rory

    Rory Senior Member

    Carry on, gents: fascinating stuff.

    Just as an aside:
    Not all milk or milk products are pasteurised. And the measurements quoted there are specific to the US; but don't mean much to the rest of the world. Would using litres be okay?

    As a long time non-milk drinker, looking forward to more of this. Thanks for the education. :)