Is Milk Really That Good for You?

After recently spending four days in Cleveland at a bioethics conference I came away with several new, and renewed, perspectives on women’s health issues.  The first that comes to mind is something that my roommate, another bioethics graduate student, and I discussed.  That is early menarche in females.

Now, a little personal background:  I was one of the last girls my age at school to begin menstruating.  I was 11 years and 10.5 months old.  Virtually all of my friends started menstruating at 10 years of age, some at 9, and a few at 11.  I really can only think of one friend who began menstruating after me (12 years old).  To men or other folks reading who wonder:  yes, many women really do talk to each other about such things.

Scientists have not conducted any truly conclusive or in-depth studies to determine why women are experiencing puberty (not only menstruation) earlier and earlier. There are several theories, the most supported being that modern food supplies are riddled with steroid hormones.  Most research that has been done along these lines ignores the effects of hormone-filled foods on early onset puberty.  Instead, the research has focused on the effects of these foods on the incidence of cancer:  breast and prostate especially.

A scientist at Harvard has conducted some rather interesting research in this area.  She found that the amounts of hormones in Mongolian milk are tiny compared to those found in Japan.  Mongolians utilize a more traditional mode of milking cows:  milking them only when they are not pregnant or at least only during the early months of pregnancy, which is about five months of the year.  In more developed nations, cows are milked around the calendar and encouraged to bear as many calves as possible, thus increasing the amount of estrogen found in dairy products 33-fold.  It is fairly well established that the greater one’s exposure to estrogen (and other hormones) the higher one’s risk becomes of developing cancer.  That can be the topic of another post another day.

Another source of such extraneous steroid hormones in our diets comes from our meat supply.  It is illegal in the United States to inject poultry and hogs with hormones.  Beef and lamb, however, are treated with hormones.  (Poultry is commonly treated with antibiotics but this rarely poses a threat to gynecological health.)  Scientists say, however, that because the hormones in our meat supply are often artificially derived (such as zeranol, trenbolone acetate, and melengestrol acetate) they do not wreak as much havoc on the human body as the natural hormones produced in cow’s milk.

So, is milk really that good for you?  I lean towards not as good.  However, I will still be eating my bowl of cereal every morning with a heaping serving of 2% milk.  Oh, incidentally, the above-mentioned Harvard scientist found that skim milk has much lower amounts of hormones similar to the milk in Mongolia.  In any event, this topic definitely warrants deeper investigation and my unprofessional opinion is that parents out not allow their children, particularly daughters, to drink milk unless it is skim until after menarche.  Questions?  Comments?  Let ‘er rip!


5 thoughts on “Is Milk Really That Good for You?

  1. I certainly began my period early. It was the week after I turned 9. I was the youngest girl in my class to start and the only third grader that had to go to the nurse’s office to get maxi pads (we weren’t allowed to carry purses yet). Incidentally, my twin sister began her period nearly two years after me. She was ten, but she was turning eleven within a few weeks.

    Do you know anything about organic milks from the US? Would the hormones still be present in that milk? If not, how would you feel about children, particularly daughters, drinking organic milk instead? One great brand is Horizon.

    Also, as a pregnant woman, I have to wonder about how the hormones are affecting my unborn child. I’ve been told repeatedly by my doctor to get at least three servings of dairy a day. Needless to say, I’m consuming a lot of milk through these months.

  2. Oh my. You mean drinking milk could enhance early menstruation? I know hormones are injected into chickens in Australia which is responsible for young girls developping early but didn’t know about milk!!

  3. Ah, yes! Thank you two for commenting. I should have made it extra clear that milk in it self is not bad, the fat in the milk is what can be dangerous. The fat carries the hormones and other chemicals that could be dangerous. And because estrogen in the American milk supply is a naturally occurring hormone in cows, organic milk also contains the same estrogen-related risks as non-organic milk. Organic milk does not contain protein hormones (i.e., bovine growth hormone), which are really not a danger to humans as our digestive tract destroys them before they can do any damage. Additionally, soy milk (surprisingly, to me) contains major amounts of estrogen as well.

    Actually, speaking of babies, nearly 1/4 of baby formula in the US is made from a soy base, higher than most other nations. Soy contains phytoestrogen, the plant equivalent (if you will) of estrogen. Researchers in New Zealand ( found that feeding a baby exclusively on soy-based formula is the equivalent of giving the baby five birth control pills each day.

    The easiest way, I think, of avoiding these high amounts of hormones in dairy would be to buy low- or no-fat milk, cheese, etc. It might taste like dreck, but it is less dangerous in my unprofessional opinion. Actually, one way I supplement my calcium intake (assuming that is why doctors recommend three servings of dairy or more each day) is by eating rolaids/tums/what-have-you. Many now come in delicious flavors, like candy, and they have high amounts of calcium. I have been told the body absorbs the calcium from tums, etc, somewhat better than it does from supplemental pills.

    Honestly, at the end of the day, it sounds increasingly like everything in the world is unhealthy, dangerous, and carcinogenic. So, don’t curb your dairy intake or that of your child unless a doctor specifically recommends it or a future study proves conclusively that American-style milk is very bad for you.

    (PS: The reason, in my opinion, that the levels of estrogen in milk cause more women’s cancers–though I cannot truly speak to men’s cancers–is it hastens menarche therefore hastening self-originating estrogen. The more menstrual periods a woman has in a lifetime greatly increases her exposure to estrogen and, therefore, her chances of developing cancer. Another way to shorten a woman’s exposure to estrogen other than postponing menarche is to have babies! Pregnancy greatly lowers a woman’s exposure to self-originating estrogen and really does have some long-term perks.)

    (PS: Soy milk (and soy-based formula) is not-so-good for boys, either. It can delay their entry into puberty, possibly give them female secondary-sex characteristics such as breasts and lack of facial hair. Other side effects are possible such as low sperm count.

  4. I find it very interesting that the synthetically derived hormones are not thought to have as many adverse effects as those that naturally occur in the milk, and I wonder at the reason for this.

  5. I’m glad you brought that up, Jon. I cannot truly reconcile it myself, not being a scientist. But I think it has something to do with the body recognizing the synthetic hormones as foreign to the body and destroys them more readily that the ones that are naturally present, which the body accepts, processes, and suffers from if too much. Then again, maybe I’m completely wrong. What say you young biologist?

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