January 20, 2008

Back in December, Mountain Equipment Co-op and Lululemon pulled Nalgene plastic water bottles from their shelves amidst concerns over bisphenol A. Also known as BPA, bisphenol A is the building block of polycarbonate, a clear hard plastic.

Everyone joined the outdoor enthusiasts and yoga gurus in panic, because after all, who hasn’t drank water from plastic bottle before?

Did You Know?
Polycarbonate is everywhere. It is found in eyeglass lenses, dental sealant, medical equipment and tubing, DVDs, laptops, lining water pipes, Tupperware and iPods. Though previously perceived to be harmless, there are now oodles of evidence that polycarbonate can leach BPA into water. BPA is also fat-soluble, making it super easy to be absorbed by your body, which is why scientists have detected significant amounts of BPA in human blood, urine, and semen.

Babies are at a particular risk. Not only are baby bottles made of polycarbonate, but BPA has been found in breast milk, amniotic fluid, the placenta, and the umbilical cord. This means most of us have been exposed to BPA from before we were even born!

So what’s all the fuss? BPA is dangerous because it mimics the action of estrogen, the female sex hormone. In the right balance, estrogen is fantastic – it builds strong bones, protects against heart disease, and gives Beyoncé her rocking curves.

However, it’s when there is too much estrogen action, which is what happens with BPA, that things go wrong. Some even blame constant exposure to BPA in the environment for a reason why girls are starting their periods younger than their mothers and grandmothers did.

Did You Know?
Too much estrogen is cancerous. It raises the risk of breast, vaginal, and endometrial cancer in women. For guys, it can lead to testicular and prostate cancer. If the threat of cancer is too far into the future for you to care, then consider this: BPA causes fat cells to grow larger. That’s right, BPA might make you fat! The fat is deposited around visceral organs, which can lead to diabetes and heart disease.

Also, early exposure to BPA abolishes the sexual differentiation of brain structures and neural functions, meaning guys become more feminine and girls more masculine.

Did You Know?
BPA binds the estrogen receptor on the nucleus of cells to change gene expression. Of course there are always two sides to every story, and critics argue that the levels BPA found in humans are too low to cause any real harm, and both Health Canada and the FDA insist that BPA poses no risk to consumers.

However, these harmful effects were observed in studies of mice and rats using the same dose of BPA normally found in people. It may not be exactly the same, humans and mice are pretty different after all, but it looks like a little BPA goes a long way. Both Health Canada and the FDA insist that BPA poses no risk to consumers.

In the meantime, what does this mean for your next trip to the mall? Most retailers are expected to follow the example of MEC and Lululemon, so chances are, you’ll have trouble finding those brightly coloured Nalgene water bottles.

On the other hand, there are stainless steel and polyethylene available on the market. Because regardless of the container that holds your water, it is important to always stay hydrated, and to keep those disposable plastic water bottles out of the landfills!

Learn More:

Plastics Industry BPA Information

Health Canada’s stance on BPA

What the government is doing to address the threat of BPA

Joanne Hsieh is a Ph.D. candidate in the Department of Biochemistry at the University of Toronto. Her research is on matters of the heart (actually, it’s the link between diabetes and cardiovascular disease). She’s been going out with her boyfriend for the past 3 years and thought the research for this article would help her move the relationship along.


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