Ganmaa Davaasambuu is a physician (Mongolia), a Ph.D. in environmental health (Japan), a fellow (Radcliffe Institute for Advanced Study), and a working scientist (Harvard School of Public Health).

On Monday (Dec. 4), she drew on all those roles during a lunchtime talk to most of her fellow fellows.

Ganmaa’s topic was lunch-appropriate: the suspected role of cow’s milk, cheese, and other dairy products in hormone-dependent cancers. (Those include cancers of the testes, prostate, and breast.)

The link between cancer and dietary hormones – estrogen in particular – has been a source of great concern among scientists, said Ganmaa, but it has not been widely studied or discussed.

The potential for risk is large. Natural estrogens are up to 100,000 times more potent than their environmental counterparts, such as the estrogen-like compounds in pesticides.

“Among the routes of human exposure to estrogens, we are mostly concerned about cow’s milk, which contains considerable amounts of female sex hormones,” Ganmaa told her audience. Dairy, she added, accounts for 60 percent to 80 percent of estrogens consumed.