In a finding that contradicts longstanding claims by the American Dairy Council, the Harvard Nurses health study has found an association between milk, particularly skim milk, and acne. The most likely explanation is the hormone content in the milk, which is present in both organic and conventional milk.
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.”