This article first appeared in the St. Louis Beacon: October 7, 2008 - More than 50,000 Chinese infants are seriously ill this week because of a failure of Chinese government food safety regulators to do their job. The toxic chemical melamine was being added to baby food milk to disguise the fact that the milk had been diluted to raise milk dealers' profits. Regulators missed this because they were relying upon a cheap and easily fooled test.
Effective regulation of the marketplace serves a serious function, and its failure can have serious consequences. This hard lesson is always obvious in retrospect -- anyone reading about melamine-laced candy from China or the meltdown on Wall Street sees the point clearly. Unfortunately, the need for effective regulation is not always so obvious before the fact.
Nowhere is this sad lesson more clearly illustrated than in the Bush administration's failure to effectively regulate our exposure to the toxic chemical bisphenol A, or BPA. Few manufactured chemicals are more widespread than BPA.
Since the 1950s, BPA has been widely used in plastic food packaging, metal can linings and clear plastic baby bottles. More than 6 million pounds of BPA are produced in the United States each year by Dow Chemical, BASF, Bayer AG and other manufacturers. Because people ingest BPA that leaches from containers into food and drink, everyone of us is exposed to it every day. BPA can be detected in the blood and urine of 95 percent of Americans.
The problem with this almost-universal exposure is an increasing body of evidence that BPA may not be safe. To appreciate what this evidence is telling us, it is best to look at how BPA acquired its dangerous reputation among research scientists.
Let's start by looking at BPA the way a scientist does, as a chemical. What does its structure tell us?
A very important thing: BPA looks a lot like the sex hormone estrogen (more formally, 17b-estradiol). Molecules that mimic natural hormones are called endocrine disruptors. Scientists have known for years that even trace amounts of BPA and other hormone disruptors can disrupt sexual development, as well as alter glucose metabolism.
In recent years, hundreds of studies in laboratory animals and cell cultures have suggesting that BPA poses serious risks to health, particularly to infants, who are exposed to more than 12 times as much BPA per pound of body weight as adults. This month, the National Toxicology Program expressed "some concern" that BPA alters the brain and behavior of infants and small children. Recent studies in laboratory animals have also suggested that BPA may be a cause of breast cancer in women -- this finding alone ought to have been enough to alert the FDA to potential danger.
What the FDA did instead was to issue a report based on three studies funded by the chemical industry. This report, ignoring the large body of research indicating potential danger and many of the studies considered by the National Toxicology Program in its assessment, found instead that BPA doesn't pose a risk at the levels to which people are commonly exposed. The FDA responded that it relied on these chemical industry studies - studies that independent researchers criticize as flawed -- because the industry studies were very large, with lots of raw data to analyze.
After a firestorm of criticism by scientists who had been investigating the potential dangers of BPA, the FDA agreed to have its assessment of BPA's safety reviewed by an independent panel of scientists, which met last week. The independent panel proved to be a little less independent than some might have liked -- a subcommittee of the FDA science board that oversaw production of the draft report. About 20 people spoke to the panel at the hearing, most of them opposed to the use of BPA.
The loudest voice at the hearing, however, was not a person, but a research paper published online that day in The Journal of the American Medical Association, the first large study of BPA in humans. The research team, led by David Melzer of the U.K., used data collected by the Center for Disease Control and Prevention in 2003 and 2004. This study looked at BPA levels in the urine of 1,455 adults aged 18 to 74. They found that individuals with the highest BPA levels were more than twice as likely to have diabetes and heart disease than those with the lowest levels. BPA, this suggests, may cause diabetes and contribute to heart disease.
The result was not really a surprise to the researchers who had suspected there might be a link because of the way BPA disrupts glucose metabolism. Researchers in 2006 had tested BPA's effects on metabolism by measuring glucose and insulin levels in mice treated with BPA, compared with control individuals treated with corn oil. The corn oil had no effect, but BPA caused a rapid oversecretion of insulin! The dose high enough to cause this insulin resistance was in the same range (50 micrograms/kg/day) as claimed safe by the FDA. The scary conclusion: BPA induces diabetes in mice.
Last week's human study was the logical next step in investigating this worrisome possibility. The study's result is important because it establishes that the link between BPA and diabetes is not some kind of fluke.
The FDA is quite right to point out that the result does NOT establish cause and effect. Much more detailed clinical studies will be required to firmly establish a causal link.
What the study DOES do, however, is indicate that such a link is a distinct possibility that should be evaluated. That is how science is supposed to work, one step at a time.
But the FDA's response to the human study -- Well, let's wait and see -- is NOT how regulation is supposed to work. When preliminary studies suggest a serious public health hazard, cautionary steps should be taken while further research is carried out. At the very least, the review panel should recommend in its report that the FDA require a prominent warning on any bottle or can made with BPA, so consumers who wish to can avoid them.
The price of the lack of regulation that has characterized the FDA's unwillingness to regulate BPA is that the American public is kept ignorant of information that may seriously affect the health of each one of us, and our children.
We need leaders in Washington who understand the vital role of truly independent science, of rigorous regulation of the food and drug industries and an administration that carries out its statutory mandate to protect consumers' health first and foremost.
'On science'
George B. Johnson's "On Science" column looks at scientific issues and explains them in an accessible manner. There is no dumbing down in Johnson's writing, rather he uses analogy and precise terms to open the world of science to others.
Johnson, Ph.D., professor emeritus of Biology at Washington University, has taught biology and genetics to undergraduates for more than 30 years. Also professor of genetics at Washington University’s School of Medicine, Johnson is a student of population genetics and evolution, renowned for his pioneering studies of genetic variability.
He has authored more than 50 scientific publications and seven texts, including "BIOLOGY" (with botanist Peter Raven), "THE LIVING WORLD" and a widely used high school biology textbook, "HOLT BIOLOGY."
As the founding director of The Living World, the education center at the St Louis Zoo, from 1987 to 1990, he was responsible for developing innovative high-tech exhibits and new educational programs.