Sunday, January 27, 2013

Environmental Chemicals Cause Obesity?

New York Times journalist Nicholas Kristof led off a recent article with this photo:

He said:
"[The mice are] genetically the same, raised in the same lab and given the same food and chance to exercise.

The only difference is that the top one was exposed at birth to just one part per billion of an endocrine-disrupting chemical. The brief exposure programmed the mouse to put on fat, and although there were no significant differences in caloric intake or expenditure, it continued to put on flab long after the chemical was gone."
Here's the study:
Developmental Exposure To Estrogenic Compounds And Obesity, Birth Defects Research, 2005

The endocrine-disrupting chemicals used in this study were:
  • DES (Diethylstilbestrol, a synthetic estrogen prescribed in the 1950s-1960s to prevent miscarriage. Was withdrawn in 1971 after it was found to cause cancer in offspring.)
  • Estrodial (Estradiol is the predominant estrogen in premenopausal women.)
  • Genistein (A phytoestrogen found in some plant foods, notably soybeans. Has antioxidant and antiinflammatory properties.)

All of them resulted in overweight mice. Exposure was during the first 5 days after birth. The authors concluded:
"Our data support the idea that brief exposure to low levels of environmental estrogens early in life increases body weight as the mice age."
Some other environmental estrogens are PCBs (bioaccumulate and end up in animal food), BPA (found in can linings, register receipts) and phthalates (found in plastics). You can do a search on "xenoestrogens" for more.

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