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 lot of dairy.  Many studies have shown a positive correlation between high dairy consumption and estrogen-driven cancers, so is it really surprising that dairy consumption in particular could be related to early-onset puberty?  Not to me.

There’s another factor to consider, as well.  Plastics and other chemicals, which have become so ubiquitous these days, frequently contain certain chemicals that can mimic the role of estrogen in the body.  Chemicals that act this way are called endocrine disruptors, and they’re extremely common in everything from water bottles to cosmetics.  This article discusses research conducted at the Mount Sinai School of Medicine, which found that endocrine disrupting chemicals are partly to blame for early onset puberty.  Phthalates are one of the most common classes of these chemicals, and are found extesively in cosmetics, detergents, and soft plastics, among many other products. 

So what can you do to limit your and your childrens’ exposure to these hormones and chemicals?  Regarding food, try eating more plant-based proteins (nuts, seeds, legumes), instead of animal proteins (meat and dairy) a few times a week.  When you do eat milk and dairy, try to find food sources that raise animals the old-fashioned way.  This probably means a trip to your farmer’s market.  Ask the farmer questions, I promise you’ll have a fascinating conversation!  Regarding chemicals – try to reduce and avoid your exposure wherever possible.  Buy organic and phthalate-free cosmetics and cleaners, and reduce your use of plastic food containers.  Heating plastics makes their chemicals more volatile, so never put plastic or plastic wrap in the microwave or oven.  Glass tupperware, by the way, is a fantastic alternative and is widely available – even at Target

If you have any other good tips, email me at and I’ll post them!