Elizabeth Weil writes in the New York Times, asking Puberty Before Age 10: A New ‘Normal’?, concluding that it is happening, but what are the contributing causes? They appear to include obesity:
As Robert Lustig, a professor of clinical pediatrics at the University of California, San Francisco’s Benioff Children’s Hospital, explains, fatter girls have higher levels of the hormone leptin, which can lead to early puberty, which leads to higher estrogen levels, which leads to greater insulin resistance, causing girls to have yet more fat tissue, more leptin and more estrogen, the cycle feeding on itself, until their bodies physically mature.
Also of concern are endocrine disrupting chemicals, including flame retardants and Bisphenol A. (TreeHugger would add phthalates to the list). Parents are trying everything with their kids:
Some trained with them for 5K runs (exercise is one of the few interventions known to help prevent early puberty); others trimmed milk and meat containing hormones from their daughters’ diets; some purged from their homes plastics, pesticides and soy.
In the end, Weil cannot come up with any good recommendations or pin down any specific causes. With respect to chemicals, she quotes an author:
Even if we could read every label and scrutinize every product, our kids are in schools and running in and out of other people’s homes where there are brominated flame retardants on the furniture and pesticides used in the backyard.
But there are choices one can make to reduce exposure that everyone should be taking, and not just for girls but for boys too. TreeHugger and Parentables have covered some of these issues:
Brian wrote two years ago:
One of the reasons that earlier puberty rates concern scientists is that it puts women at a higher risk of breast cancer, due to a longer "lifetime exposure to the hormones estrogen and progesterone". Early puberty can also be emotionally and psychologically damaging to girls. Furthermore, researchers worry that if the change is being triggered by an environmental factor, like exposure to a chemical, then there may be an additional cancer risk therein.
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Buy in bottles, not cans. Many products, like tomato sauces, are available in bottles as well as cans. Does that white epoxy on the inside of the metal lid have BPA? Probably, but there is a lot less surface area than the whole inside of a can. Start cooking instead of just heating. The fact that 17% of the American diet comes out of cans is just a scandal when we are surrounded by fresh food. Cook it from scratch and avoid the problem altogether.
So now we know what happened; Mom ate too much canned tomato sauce and drank out of an old polycarbonate bottle. According to a new study, prenatal exposure to Bisphenol A (BPA) makes little girls as mean and aggressive as little boys.
Our chemist Christine explains how such small quantities of endocrine disruptors make such a big impact. More in TreeHugger
Is it the obesity, or the Bisphenol A, or are they related?
Phthalates are a plasticizer for vinyl or PVC; it is not chemically bound but mixed in, so it can leach out easily. It has been linked to hormonal changes, genital abnormalities, early puberty and even claims of reduced penis size. More in TreeHugger
Chemist Christine lists the chemicals that may cause obesity, suspected of being one of the causes of early puberty:
- Atrazine, banned in Europe but still one of the most widely used herbicides in the world
- Breakdown products of DDT - the Silent Spring insecticide, widely restricted but still used to control insect-transmitted diseases and still present in the environment due to past use and contamination from disposal sites.
- Organotins, including dibutyl tin which is used as a stabilizer in PVC (vinyl, or fake leather)
- Phthalates, which stabilize plastics and are also commonly found in products with fragrances, such as air fresheners, laundry products, and lots of items on the bathroom shelf.
- Bisphenol-A (BPA), found in plastic bottles, cash-register receipts, and tin can linings
- Perfluorooctanoic acid (PFOA), used in coatings for non-stick and water repellent properties
- Even dietary sources such as soy phytoestrogens or monosodium glutamate (msg) are implicated in weight gain.
More in Parentables
Flame retardants are even in our cute baby polar bears.
Flame-retardants are in widespread use in both the U.S. and Canada, primarily in carpet padding, foam cushions, polyester bedding and clothing, wallpaper, and the plastic housings for computers, faxes and other electronics. Most are made from variations of a chemical known as PBDE, which stands for polybrominated diphenyl ether.
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Finally, I should point out that our building materials are just full of this stuff. Our insulations and foams are full of fire retardants, our vinyl floors are full of phthalates, and every can of pop or tomatoes is lined with BPA. Every time you take a receipt at the store, the thermal paper is made with BPA. It is almost impossible to avoid these chemicals. I am not sure that I agree completely with what Sandra Steingraber said in the New York Times,
This idea that we, as parents, should be scrutinizing labels and vetting birthday party goody bags — the idea that all of us in our homes should be acting as our own Environmental Protection Agencies and Departments of Interior — is just nuts.
But we can start reducing the amounts of it in our kids by reducing our consumption of canned foods and drinks; by building healthier houses; by cooking our own food instead of heating it and by demanding European style chemical regulation in America.