Tuesday, May 26, 2009

Harvard study backs bottle concern

Harvard study backs bottle concern

Says plastic used leaches bisphenol A

A Harvard study released yesterday supports what many public health specialists have long assumed: Hard plastic drinking bottles containing bisphenol A are leaching notable amounts of the controversial chemical into people's bodies.

Researchers from the Harvard School of Public Health found that people who drank for a week from the clear plastic polycarbonate bottles increased concentrations of bisphenol A - or BPA - in their urine by 69 percent.

The study is the first to definitively show that drinking from BPA bottles increases the levels of the chemical in urine, researchers said. It was published on the website of the journal Environmental Health Perspectives.

BPA is used in hundreds of everyday products. It is used to make reusable, hard plastic bottles more durable and to help prevent corrosion in canned goods such as soup and infant formula.

"If you heat those bottles, as is the case with baby bottles, we would expect the levels to be considerably higher," said Karin B. Michels, senior author of the report and associate professor at the School of Public Health and Harvard Medical School. "This would be of concern since infants may be particularly susceptible to BPA's endocrine-disrupting potential," she said.

Canada banned the use of BPA in baby bottles in 2008, and Massachusetts health officials are now weighing whether to warn pregnant women and young children to avoid food, drinks, and other items containing the chemical.

Numerous animal studies in recent years suggest that low levels of BPA might cause developmental problems in fetuses and young children and other ill effects. The health effects on adults are not well understood although a recent large human study linked BPA concentrations in people's urine to an increased prevalence of diabetes, heart disease, and liver toxicity.

The Food and Drug Administration has said that products containing BPA are safe and that exposure levels, including those for infants and children, are below those that would affect health. But the FDA's own scientific advisory board criticized agency officials for relying on industry-funded studies to declare the chemical safe.

Michael L. Herndon, an FDA spokesman, said in e-mail to the Globe yesterday that newly appointed chief scientist Jesse Goodman will "provide new leadership and take a fresh look at this important issue from a scientific and policy position, incorporating emerging science and appropriate input from both inside and outside the agency."

Yesterday, an official with the American Chemistry Council discounted any suggestion that the Harvard study underscores a health risk.

In an e-mail, Steven G. Hentges said the study shows that exposure to bisphenol A from use of the bottles is "extremely low" and below the mean BPA amounts reported by the Centers for Disease Control and Prevention for the US population, "indicating that even exclusive use of polycarbonate bottles does not lead to unusually high levels of bisphenol A in the urine."

The Harvard study was sparked by a discussion in Michels's class after she warned students who regularly swigged water from hard plastic bottles that they might want to limit their BPA exposure. The students countered by asking how much BPA they were getting from the bottles - and soon, a study was born.

Led by Jenny Carwile, a Harvard School of Public Health doctoral student, 77 Harvard students in the study drank all cold beverages from stainless steel bottles for a week to wash BPA out of their bodies and minimize exposure. Most BPA is flushed from people's bodies within a matter of hours. During that week, the students gave urine samples.

Then the students were given two refillable polycarbonate bottles made with BPA to drink all cold beverages from for one week. Urine samples taken over that week showed the students' BPA levels spiked the second week to levels normally found in the general population. Because the students did nothing different in their schedules other than drink from the BPA bottles, the researchers determined their urine concentrations largely came from the bottles.

"While previous students have demonstrated that BPA is linked to adverse health effects, this study fills in a missing piece of the puzzle - whether or not polycarbonate plastic bottles are an important contributor to the amount of BPA in the body," said Carwile.

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