Remember the backlash against the use of recombinant bovine growth hormone (rbGH)? Many commercial dairies now market their milk as free of this synthetic hormone, but that label may not tell you everything you need to know. Thanks to the way it is produced nowadays, milk from a commercial dairy is likely to contain much higher levels of natural sex hormones than you’d find in milk from a traditional (pre-industrial) dairy herd. And that could pose an rbGH-type problem. Some research suggests that elevated levels of these hormones may affect childhood development and raise a person’s cancer risk.

“The milk we drink today is quite unlike the milk our ancestors were drinking,” Harvard researcher Ganmaa Davaasambuu, an expert on milk-related illnesses, said during a 2006 talk at the Radcliffe Institute for Advanced Study. It “may not be nature’s perfect food.”

In the early 2000s, Davaasambuu began investigating why the rate of prostate cancer in Japan, while much lower than that of the United States, had increased 25-fold over the past 50 years. She and a colleague, the Japanese doctor Akio Sato, examined 36 years of dietary data in Japan and found that the incidence of, and mortality from, prostate cancer correlated most […]