BPA-Spiked Urine: New Study Points to Polycarbonate Bottles
Drinking from a polycarbonate bottle for just one week can increase the amount of BPA in your body by nearly 70 percent, a new study out of Harvard School of Public Health suggests. Photo by Ben Garney via Flickr.com.
UPDATE: This post was updated from its original version on 6/15/09.
It's hard to miss the focus on bisphenol A (BPA)—we know it leeches from bottles and cans into beverages and foods. But a new study out of the Harvard School of Public Health is the first to make a direct link between urinary BPA levels and drinking from polycarbonate bottles, a material widely used for baby bottles and drinking containers.
The results of the study are unsettling: After just one week of drinking all cold beverages from polycarbonate bottles, BPA concentrations in the participants' urine increased by an astounding 69 percent, from 1.3 μg/L creatinine before using the bottles, to 2.1 μg/L after using the polycarbonate bottles for a week. A 2008 Centers for Disease Control study listed the national geometric urinary BPA mean at 2.6 μg/L.
These findings offer a key piece of evidence in the search for the health impact of BPA. The Harvard doctoral student who led the research, Jenny Carwile, explains:
While previous studies 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.
It is important to note that the study was not looking at how much BPA accumulates in the body, but at the amount of BPA that makes its way through the body before it is expelled.
Critics may automatically think the BPA detected could be linked to other sources of BPA exposure, but it's unlikely.
The study's 77 participants—all students at Harvard—followed a generally uniform routine, week over week, including eating in campus dining halls.
The participants also went through a week-long "washout" phase in which they drank all cold beverages from reusable metal bottles, in this case, new Kleen Kanteen bottles, which are BPA-free. Orally administered BPA has a half-life of about six hours, and it is eliminated from the body after about 24 hours, so a week-long cleanse was deemed sufficient.
The following week, participants drank all cold beverages from the polycarbonate bottles they were provided with. The bottles used in the study were new Nalgene Lexan narrow mouth and Nalgene Lexan wide mouth bottles.
Fruit juices, carbonated beverages and drinks such as Gatorade can increase BPA leeching, but the study did not place restrictions on which beverages students could drink from the bottle. Participants were, however, instructed not to fill their containers with water from coolers placed in the dining halls.
It is also important to note that participants did not drink hot beverages from the bottles and they didn't wash their bottles in a dishwasher, as many people do. Heat from either of these sources could have yielded an even greater increase in urinary BPA, says Karin B. Michels, associate professor of epidemiology at the Harvard School of Public Health and Harvard Medical School and senior author of the study:
If you heat those bottles, as is the case with baby bottles, we would expect the levels to be considerably higher. This would be of concern since infants may be particularly susceptible to BPA's endocrine-disrupting potential.
Each participant provided urine samples on two of the last three days at the end of each week in order to prevent unusually high or low levels from affecting the results.
BPA Bans in Baby and/or Infant Products
With concern over the health impacts on infants and toddlers, governments at all levels have moved toward banning BPA in food-related products geared at infants and toddlers. The areas currently banning BPA include:
MinnesotaChicagoSuffolk County, NYCanada
Similar laws are being considered in California and Connecticut. And according to Renee Sharp, the director of the Environmental Working Group's California office, sweeping change across the country is necessary:
These astonishing results should be a clarion call to lawmakers and public health officials that babies are being exposed to BPA, and at levels that could likely have an impact on their development.
But what about older kids and adults? Should we accept BPA exposure as something we just have to deal with—or go to great lengths to avoid? If nothing else this study shows BPA levels in adults should also be a cause for concern.
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