September 21, 2009

Plastics, the Silent Obesogens

Hmm... That title doesn't quite seem to capture the seriousness of the issue, does it? But despite rampant skepticism, the data continue to pour in -- chemicals in some of the most common plastics and household products, things that surround us every minute of the day, are major culprits in the obesity epidemic. At least now that fact is now getting some well-deserved attention. From Newsweek:
Evidence has been steadily accumulating that certain hormone-mimicking pollutants, ubiquitous in the food chain, have two previously unsuspected effects. They act on genes in the developing fetus and newborn to turn more precursor cells into fat cells, which stay with you for life. And they may alter metabolic rate, so that the body hoards calories rather than burning them, like a physiological Scrooge. "The evidence now emerging says that being overweight is not just the result of personal choices about what you eat, combined with inactivity," says Retha Newbold of the National Institute of Environmental Health Sciences (NIEHS) in North Carolina, part of the National Institutes of Health (NIH). "Exposure to environmental chemicals during development may be contributing to the obesity epidemic." They are not the cause of extra pounds in every person who is overweight—for older adults, who were less likely to be exposed to so many of the compounds before birth, the standard explanations of genetics and lifestyle probably suffice—but environmental chemicals may well account for a good part of the current epidemic, especially in those under 50. And at the individual level, exposure to the compounds during a critical period of development may explain one of the most frustrating aspects of weight gain: you eat no more than your slim friends, and exercise no less, yet are still unable to shed pounds.
Note that this phenomenon really hits kids hardest (as does the obesity epidemic), both because of fetal and childhood exposure, and also because of the fact that these products have only become truly ubiquitous since the eighties. Indeed, to my mind, the clincher comes in the fat babies. Or as Newsweek puts it:
...[T]hese [other] causes cannot explain the ballooning of one particular segment of the population, a segment that doesn't go to movies, can't chew, and was never that much into exercise: babies. In 2006 scientists at the Harvard School of Public Health reported that the prevalence of obesity in infants under 6 months had risen 73 percent since 1980. "This epidemic of obese 6-month-olds," as endocrinologist Robert Lustig of the University of California, San Francisco, calls it, poses a problem for conventional explanations of the fattening of America. "Since they're eating only formula or breast milk, and never exactly got a lot of exercise, the obvious explanations for obesity don't work for babies," he points out. "You have to look beyond the obvious."
And what's beyond the obvious? Plastics.

Children's Health Magazine recently did a story on "Your Big Fat House" that uncovered just how common these -- as one scientist has dubbed them -- "obesogens" are in your home:
Carpet (PBDEs), vinyl flooring (PVC), mattress (PBDEs), toys, (BPA), waterproof clothing (Phthalates, PFOA)

Raincoats (phthalates), rain boots (phthalates), faux leather coats, shoes, purses, and briefcases (phthalates)

PVC pipes, detergents, and dryer sheets (phthalates)

Carpet (PBDEs), air fresheners (phthalates), furniture (PBDEs), electronics (PBDEs)


Toothbrush (BPA), toothpaste, vinyl shower curtain, water from the shower comes through PVC pipes, soaps, shampoos, deodorants, creams, powders, and makeup (Phthalates), nail polish (Phthalates, PFOA)

Produce in the fridge (pesticides), meat in the freezer (PBDEs, PCBs, pesticides), canned food in the pantry (BPA), jars of peanut butter (phthalates), jars of tomato sauce (phthalates), jarred baby food (BPA), plastic cups, baby bottles, plates, and utensils (BPA)
Now you can probably find a way to eliminate some of these, especially in the bathroom and the kitchen. But are people going to rip up their vinyl floors and throw out ALL their children's toys (not to mention those precious consumer electronics). And for many products how are you even supposed to find out if they contain these chemicals? In theory, you have to seek out products that declare their "status." But really. Are we seriously expected to junk the entire contents of our houses? The advice that comes with the article tries to make this into one of those issues that can be solved by a good spring cleaning. Clearly, we're way beyond that.

In June, the NYT's Nick Kristof had an article about this class of chemicals and the danger they pose to ourselves and the environment. And he lamented the EPA's "glacial pace" in addressing them -- truly glacial if you realize that, though the connection to obesity is new, scientists have been aware of the existence of endocrine disrupting chemicals for decades. But the reason is obvious, isn't it? These chemicals are in EVERYTHING. Truly everything. The "disruption" to manufacturers at every level is mind-numbing. We're not talking about phasing out Freon here. This is about reformulating some of the fundamental ingredients to just about every major consumer item.

Plus, to go ahead and ban them would not only force our friends in industrial chemicals and the oil industry (most of these products come from oil, remember) to find safe alternatives, which in some cases might be impossible. But all these suppliers (and the consumer products companies that incorporated these poisons into their offerings) would also be open to massive liability lawsuits.

But the Newsweek piece concludes with the suggestion that even the EPA understands that the issue can't be ignored for much longer:
This fall, scientists from NIH, the Food and Drug Administration, the Environmental Protection Agency, and academia will discuss obesogens at the largest-ever government-sponsored meeting on the topic.
For this to lead to real change, of course, it will take more than articles in Newsweek and expert panels (and immunity from lawsuits which all these companies will inevitably be granted). What we need is outrage and consumer revolt. Anyone know where to find that?

Photo by tuppus used under a CC license

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Blogger Marc said...

For the story of how Europe is responding to the threats of BPA / Pthalates / etc by reinventing products, doing innovative chemistry, dumping the toxic junk on the U.S., and not going bankrupt, check out the book "Exposed" by Mark Schapiro. I wrote about his work at the Ethicurean last year and included links to a few of his radio appearances.

Living on Earth had an interesting segment about the toxicology of low doses a few weeks ago. The Living on Earth website has the full transcript and MP3 version for download. Here's an excerpt from the transcript:

[Dr. J. Peterson]MYERS [CEO and chief scientist of the non-profit Environmental Health Sciences]: Our regulatory safety net, the FDA or the EPA, the all depend upon a core assumption – that when they test at high doses those tests will reveal what's happening at low doses. The problem is that when you're dealing with contaminants that behave like hormones, it doesn't work that way.

They do one thing at high doses and potentially something completely different at low doses. So if you are dependent upon high dose testing which is the way our system works, you will never see the low dose effects. And what that means is all of the high dose testing that we've done for decades have been blind to this type of effect.

[Jeff] YOUNG [of Living on Earth]: Why is it that these chemicals can start to show problems at low doses instead of at high doses?

MYERS: What hormones and these contaminants do is at very low doses they turn on and off genes. Genes are being turned on and off trillions of times a second throughout your lifetime. And the orchestration of that is absolutely vital to life. If the genes get turned on or off at the wrong time, that's gonna lead to a problem. You're gonna lack a protein that might be important for example in suppressing a tumor or in controlling the growth of your heart. And the body's control system for these genes is designed to function at really, really low levels.

YOUNG: How low are we talking about?

MYERS: We're talking parts per trillion to parts per billion to low parts per million.

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