MELISSA BLOCK, Host:
A chemical commonly found in water bottles, baby bottles, and food cans might cause cancer, early puberty, and neural and behavioral changes. That's the conclusion of a draft report by a federal health agency, The National Toxicology Program. The report was based on studies of animals.
The chemical is Bisphenol A, or BPA. And the report says the possibility that BPA may alter human development cannot be dismissed.
Dr. Michael Shelby oversaw the report, he's director of the Center for the Evaluation of Risks to Human Reproduction.
Dr. Shelby, welcome to the program.
D: Thank you.
BLOCK: When we say that BPA is a common chemical. How common is it?
D: Well, it's a very common chemical. It's used in a wide variety of consumer products, and results from the Centers for Disease Control and Prevention show that more than 90 percent of people in the U.S. have metabolites of Bisphenol A in their urine.
BLOCK: The water bottles that I mentioned - this would be clear hard plastics and the recycle number seven on the bottom, is that right?
D: That's correct.
BLOCK: And also I've read cans of instant formula that might have BPA in the lining.
D: That's also correct.
BLOCK: Your studies seems to show that its fetuses, babies, and children who are potentially most at risk here, is that right?
D: That's correct.
BLOCK: And why is that?
D: Well, it's because that age group undergo a tremendous amount of development much of that development is influence by hormones in the body. And Bisphenol A has been shown to have weak hormonal effects.
And so, they're in a susceptible period of their lives. In addition the evidence that we have today suggests that infants and children are exposed to higher level of Bisphenol A that the rest of the population.
BLOCK: Let's talk about some of those effects that were shown in your study. This was - this were studies done on rats. What turned up, what effects did you see?
D: Some researchers report changes or alterations in tissues in the prostate gland. Other people who study the mammary gland have detected cellular changes in the breast. And still other researchers have found that exposure to Bisphenol A early in development can accelerate puberty in female mice.
BLOCK: These changes in the prostate and mammary glands that you mentioned, these were changes that seem to be headed toward cancer or pre-cancerous, I think.
D: They - some people interpret those as pre-cancerous allegiance. Although there's not the hard link between the presence of those lesions and the ultimate development of cancer.
BLOCK: You know, a lot of people listening to this conversation will be looking around their kitchens and thinking what should I do? Should I throw out my plastic baby bottles? Should I figure some other way to get instant formula? What do you tell them?
D: Well, again, we don't make recommendations to the public but its pretty clear what the sources of Bisphenol A exposure are - either drink containers or food cans. So if people are concerned they have the option of eliminating the use of those products.
BLOCK: Dr. Shelby, do you find you've changed your own behavior knowing what you know? Do you still drink from plastic water bottles? Number seven bottles?
D: Yes, I do.
BLOCK: You do. Do you have qualms about it?
D: Nope. But I'm a 64-year-old man, so I'm not much worry about doing any more reproducing or - I'm certainly past my developmental years.
BLOCK: And if you had a grandchild who is being bottle fed, would you say, hmm, maybe don't use that plastic bottle, how about a glass one, would you say that?
D: I don't have that situation to face right now. So I would have to take that under consideration. I think, if used properly, these bottles may well be safe. I mean, we just can't say whether they are or not.
BLOCK: That's a fair amount of uncertainty here.
D: That's right. Its a complex issue with a great deal of uncertainties associated with it. So, you know, boiling it down to some simple conclusion and recommendations is not an easy thing to do.
BLOCK: Well, Dr. Shelby, we appreciate your talking to us. Thanks so much.
D: You're welcome.
BLOCK: Michael Shelby oversaw the draft report on Bisphenol A for The National Toxicology Program. You can find a link to that report at our Web site, npr.org.
MICHELE NORRIS, Host:
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