NPR recently ran a story about how the average onset of puberty in girls is coming at younger and younger ages. I caught the tail end of the conversation, and since that time have had at least 4 or 5 people ask me about my thoughts – specifically whether I think it’s due to the increasing quantity of hormones in the foods we eat. It is alarming – girls as young as 6 and 7 are developing breasts and beginning menstruation, and the average age of puberty onset had dropped to only 10 years old, down an entire year in just one generation. Not only does this pose emotional challenges for these girls, but there is also an associated risk in developing breast cancer and other potential health problems later in life.
The NPR story notes research from Cincinnati Children’s Hospital which associated the puberty age change with the increase in obesity in children, as well as potential environmental and genetic factors (thanks, that’s specific). This explanation barely scratches the surface.
So what about hormones in food? It seems like pretty straight-forward logic to me that consuming estrogen-like hormones in food, essentially taking a hormone supplement, could contribute to earlier puberty. And we are consuming more hormones than ever before – in meat from animals fed growth hormones, in dairy from cows fed hormones to increase their milk production, and probably most significantly as a result of the now common-place practice of milking cows while they’re pregnant, which did not used to be the case. Dairy coming from cows that are milked while pregnant contain up to 33 times more estrogens than milk from non-pregnant cows. Thanks to USDA recommendations and marketing (Got Milk?), kids eat and drink a [...]