The National Dairy Council denies that milk intake causes acne. In my 3-min. video National Dairy Council on Acne and Milk, I profile what a study of 47,000 women supported by the National Dairy Council and performed by the Harvard Nurse’s Health Study found on the matter. As published in the official Journal of the American Academy of Dermatology, the conclusion reads: “We found a positive association with acne for intake of total milk and skim milk. We hypothesize that the association with milk may be because of the presence of hormones and bioactive molecules in milk.”
Association does not necessarily mean causation, though. From the accompanying editorial in the Journal of the American Academy of Dermatology:
“The papers… from the Harvard School of Public Health establish an association between milk consumption and acne. But how could milk cause acne? Because, drinking milk and consuming dairy products from pregnant cows exposes us to the hormones produced by the cows’ pregnancy, hormones that we were not designed to consume during our teenage and adult years. It is no secret that teenagers’ acne closely parallels hormonal activity…So what happens if exogenous hormones are added to the normal endogenous load? And what exactly is the source of these hormones? Consider that, in nature, milk is consumed from a mother, whether human or bovine, until weaning occurs. Normally, the mother then ceases lactation before the next pregnancy occurs—so that consuming milk from a mother pregnant with her next offspring is not a common occurrence. We’ve all seen nature films of animals chasing their offspring away to encourage weaning at the appropriate time. Further, in nature the offspring consumes only the milk of its own species—but both of these natural rules are broken by humans. Viewed objectively, human consumption of large volumes of another species’ milk, especially when that milk comes mainly from pregnant cows during the human’s normally post-weaned years, is essentially unnatural.”
The Harvard Nurse’s Health Study found that the association between milk intake and severe physician-diagnosed teenage acne was even more “marked for skim milk than for other forms of milk.” This may be because there is so much more estrogen in skim milk. Researchers found 15 steroid sex hormones in commercial milk right off the shelves, and the highest levels were found in skim milk, compared to 2% and whole (see my 4-min. video Hormones in Skim vs. Whole Milk).
As detailed in my 2-min. video Skim Milk and Acne, further studies of both adolescent girls and boys found the same link between milk intake and acne. This doesn’t appear to be an issue with bovine growth hormone injections or added steroids; it’s just what milk contains naturally. As a commentary in the Journal of the American Academy of Dermatology noted: “It should surprise no one that milk contains such a heavy complement of growth-enhancing hormones. Milk is, after all, specifically designed to make things grow.”
The restriction of cow’s milk consumption could have a beneficial effect on more serious epidemic diseases as well, concludes a recent review I profile in my NutritionFacts.org video pick–see above.
Michael Greger, M.D.
Image credit: Lotus Carroll / Flickr