We eat alike, talk alike and exercise alike. Yet, for reasons not yet known to scientists, a new survey has found that Americans are vastly different from Canadians when it comes to chemical exposure. Especially when it comes to BPA, or bisphenol A, an estrogen-mimicking chemical that is used in many plastics.

Laura Vandenberg is the U.S. researcher who first noticed the unusual disparity. The postdoctoral fellow at Tufts University in Massachusetts reviewed surveys done by U.S. and Canadian governments into the levels of common contaminants in their respective populations. In sifting through the data, Vandenberg uncovered that typical Americans have about twice as much BPA in their bodies as Canadians. Details of Vandenberg's research were published this week in the Canadian Medical Association Journal.

But even more worriesome than Vandenberg's findings is that health experts have absolutely no clue as to the cause.  “It’s a huge mystery,” said Vandenberg.  

BPA is used in the lining of canned foods, so scientists initially guessed that canned food consumption was the cause for the difference. But Americans and Canadians eat roughly the same amount of canned foods, and the cans themselves come from the same brand-names and often the same processing plants.

Is another dietary factor at work? Is it the five BPA manufacturing plants that are based in the U.S.? Is it some other source that scientists have yet to identify?

The plain and simple answer is that they just don't know — and that's bad news for Americans.

[via The Globe and Mail]

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