In light of the news that concerns about potential health risks associated with the chemical bisphenol A have encouraged the makers of Nalgene water bottles to pull their product off of retail shelves, it seems like a good time to remind readers of my notoriously headlined HTWW post, "Does Plastic Make Us Fat?" originally published in July 2007.
Here's how that post started.
The basic story line of "The Toxic Origins of Disease," a superb exposé in the June issue of PLoS Biology by science writer Liza Gross, fulfills a classic archetype. Publicly funded scientists determine that a commonly used substance may be harmful to human health. The industry that produces said substance responds in an all-out assault to undermine their data. Cue a lobbying firm that cut its teeth representing tobacco companies and the cast of characters is perfect.
In this case, the chemical at issue is bisphenol A, a basic building block of polycarbonate plastic, and, according to Gross, "one of the highest-volume chemicals in commercial production." A bevy of publicly funded researchers have found evidence that low doses of bisphenol A interfere with embryonic development in animals by exposing them to higher levels of hormones, such as estrogen, than normal. The chemical industry has fought back by commissioning scores of studies that find exactly the opposite. This leads to some lovely statistical info-nuggets: A survey conducted in 2005 found that of "115 published studies concerning effects of low doses of bisphenol A in experimental animals, 94 percent of publicly funded studies found evidence of harm while 100 percent of chemical industry studies found no evidence of harm."
Funny, that. This week, the National Toxicology Program released an extremely carefully worded 69-page "brief" on bisphenol A, in which, after much hemming and hawing, it acknowledged that "the possibility that bisphenol A may alter human development cannot be dismissed."
But perhaps the most startling part of Liza Gross' PLoS story was the revelation that some researchers had connected bisphenol A to obesity. Again, I quote myself:
There appears to be evidence that the damage done by bisphenol A during embryonic development may be scrambling the signals that fat cells normally receive during prenatal and neonatal development. After the initial distortion, the affected fat cells never work properly again. Affected animals are unable to properly metabolize their normal diets, leading to obesity. And guess what? The introduction of bisphenol A into the human environment in significant quantities tracks pretty closely, in timing, to the advent of the so-called obesity epidemic in the United States
The National Toxicology Program brief concludes that "There is currently insufficient evidence to conclude that bisphenol A exposure during development predisposes laboratory animals to develop obesity or metabolic diseases such as diabetes, later in life."
"More research in this area is warranted."
Fine. Just as long as that research isn't funded by the chemical companies that produce and sell the substance.
UPDATE: I am remiss in not noting that Salon also published a much more in depth look a bisphenol A shortly after my blog post. "Two Words: Bad Plastic."