Exposing the Risks of Hormone Inhibitors : OUR STOLEN FUTURE: Are We Threatening Our Fertility, Intelligence, and Survival? by Theo Colburn, Dianne Dumanoski, and John Peterson Myers; Dutton; $24.95, 306 pages
Public health officials and EPA bureaucrats are not doing their jobs informing the public of potential risks from what we now know to be hormone-inhibiting chemicals in the environment.
This book shows how, since the 1950s, scientists have pursued a variety of clues in mammals all over the world, learning that “hormonally active synthetic chemicals can damage the reproductive system, alter the nervous system and the brain, and impair the immune system. Animals contaminated by these chemicals show various behavioral effects, including aberrant mating behavior and increased parental neglect of nests.”
Four questions come immediately to mind: What are the effects of hormone inhibitors? Do humans suffer the same effects as other mammals? What kind of exposures/dosages are we talking about? And, if the risks are indeed grave, what are we going to do about them?
In the 1950s, the synthetic chemical DES (which can mimic the hormone estrogen) was routinely prescribed to prevent miscarriages and even to produce “bigger, stronger babies.” Researchers in the 1970s found signs that DES had in fact “interfered with hormone messages during development.” DES not only altered genital development in fetuses (affecting their subsequent ability to reproduce), researchers also found that it increased rates of depression and affected subsequent sexual orientation later in life.
In 1992, a team of Danish scientists released a 1940-1990 study of 15,000 men from 20 countries that showed how “some prenatal event” (such as exposure to hormone-inhibiting chemicals) had reduced the male sperm count an average of 45%.
We live with an increasing number of hormone inhibitors in our environment. The authors explain how chemicals like DES insinuate themselves into the process of hormone reception and cellular response, either mimicking a hormone or blocking that hormone’s message. Synthetic chemicals that mimic estrogen are often able to “circumvent a mechanism that protects a developing fetus from excessive estrogen exposure, which can disrupt its development.” As for the value of animal studies, scientists now understand that the endocrine system varies little among mammals, and that “hormones guide development in basically the same way in all mammals.”
In his introduction, Vice President Al Gore likens “Our Stolen Future” to the work of Rachel Carson in “Silent Spring,” written more than 30 years ago. Carson’s book was also a warning about the effects of man-made chemicals on mammals. By establishing links between these chemicals and cancer, Carson effectively alerted the public to the dangers of DDT; since then, PCBs and dioxin, among others, have been added to the toxic list. But while Carson focused on cancer, she also mentioned that “‘something more sinister’ than straightforward poisoning was occurring,” never pursuing the “clues that pesticides might impair reproduction by disrupting hormones.”
Unfortunately, the authors write, the EPA, still focusing on cancer, assumes that in the case of “noncancer hazards such as reproductive and developmental damage . . . a chemical may pose no hazard in low concentrations beneath some threshold level.” But hormone inhibitors scramble chemical messages, and the ultimate effect depends as much on the point in development at which this occurs, as well as the combined effect of other environmental factors, as it does on dosage.
“Never assume a pesticide is safe,” the authors warn. Again, the EPA “has never screened most of the pesticides on the market for hormone-disrupting activity, and U.S. Environmental Protection Agency registration is no measure of safety.”
We can only hope that more research is forthcoming, pay attention to potential risks and advocate better access to information. This book is a good start.
