18 September 2008

Bisphenol-A Reveals Flawed FDA (again)

As everyone except those without power has probably heard, bisphenol A (BPA) is one of the most widely used plastic compounds in the world. It is a common element in plastic bottles and the inside of tin cans.

There are three problems with BPA:

1) It leeches out.
2) Experiments demonstrate it has physiological effects at levels currently present in humans.
3) The FDA said BPA is safe.

Let's take the last one first. To be blunt, the FDA is a joke. Henry Waxman ways it better:

The U.S. Food and Drug Administration appears to be giving priority to projects that benefit the pharmaceutical industry rather than helping consumers, a top Democratic lawmaker said on Wednesday.

A 2007 list of top projects includes plans to offer advice to companies on promoting products, as well as guidance on offering reprints of journal articles to physicians...

The agency also planned to change its regulations to protect device makers from lawsuits as long as their products are FDA-approved with a so-called preemption clause.

"All appear to prioritize industry desires over consumer protection," Waxman wrote.

The FDA, like most of government, is more focused on corporate special interests than the public interest. If you back one political issue in your life it should be this: campaign finance reform.

But the FDA's corporate bias does not explain why it deemed BPA safe. After all, it tested the compound. What is the difference between the FDA's science and everyone else's?

The answer is toxicologists' perspective that "the dose makes the poison." If a chemical is dangerous, it will be more dangerous at higher levels. So toxicologists typically test chemicals in a high dosage range.

The problem: many chemicals, especially those that mimic hormones, can have physiological effects at both low and high levels. Sometimes the effect is completely opposite; it will have one effect at low doses, nothing at moderate doses, and the opposite effect at high doses.

So testing at only high doses does not result in a complete assessment. When the FDA tested BPA, they tested it only at levels much higher than what is found in our bodies. And they found nothing. When scientists like UC's Nira Ben-Jonathan studied it, they used it at levels found in humans. And they found something:

The researchers exposed some of the tissue to estradiol, a natural form of human estrogen, and some to bisphenol A. Both treatments suppressed the release of the protective hormone adiponectin. Adiponectin is secreted by fat cells and protects against the suite of conditions that can result in heart attacks and type 2 diabetes.

My plan: In the lab, I remember we had some glass bottles with a plastic coating on the outside. It didn't prevent breakage, but it prevented glass from flying all over the place. I'm going to look for a few of those.

1 comment:

Mark said...

The FDA only refused to endorse thalidomide due to the efforts of one woman. Today she'd be lynched on talk radio for holding up cures and being unfair to drug companies. Thank God, thalidomide wasn't developed during the Reagan administration.