Harvard Health Letter

Ask the doctor: Should I worry about health effects from BPA?

Q. Is the chemical BPA just another health scare, or is it really something we should be worried about?

A. BPA, which stands for bisphenol A, is estrogenic. That means that in some respects it behaves like the hormone estrogen. Although BPA was first developed as a synthetic estrogen, it was never used as a pharmaceutical because diethylstilbestrol (DES), another synthetic estrogen, was more potent. DES was pulled from the market in the 1970s after it was discovered that the daughters of the women who took it (extra estrogen was thought to reduce the risk of miscarriages and premature births) were more likely to have a rare type of vaginal cancer, and later studies found they also had a variety of fertility and other health problems.

But BPA turned out to have a second career, so to speak, as a compound that would be polymerized — made into long chains — to make a plastic known as polycarbonate. While not as clear as some plastics, polycarbonate is sturdy and resists shattering, so it's a great material for water bottles and baby bottles. It's used in some dental sealants and composite white fillings. BPA has proved useful as an ingredient in an epoxy resin applied to the insides of cans so the metal of the can is not in direct contact with the food or beverage. BPA is also used as an ingredient in the powdery coating found on the thermal paper that many receipts are printed on these days.

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