by Harvard Health Publications
May 20, 2008 02:38 PM EDT
By: Claire McCarthy MD


In the late 1970's, when I was in high school, a study showed that rats fed large amounts of saccharin developed bladder tumors. I was a diet soda junkie at the time, and my father was understandably concerned. "You're getting to rat levels, honey," he'd say to me as he watched me down yet another glass of the stuff. Whenever he'd say that, I'd cut back (for a while, anyway, and then he'd have to say something again). I figured that if I took in less than the rats, I'd be fine.

It turned out that the study was flawed, and in 2000 saccharin was "delisted" from the US National Toxicology Program's Report on Carcinogens. But now, as a doctor, I look back on my strategy of limiting rather than eliminating my carcinogen intake and realize that it was a crapshoot at best. Carcinogens are carcinogens; while a large exposure is bad, no exposure can be guaranteed to be truly safe. The same goes for any chemical in food or the environment that has been shown to cause harm. Less is better; with less you may be fine. But less is never better than none.

It's pretty hard to avoid all toxins these days, and sometimes doing so makes our lives less convenient or less pleasant. For example, avoiding all seafood is the best way to avoid mercury—but if you're a seafood lover like me, you might choose instead to have small amounts every once in a while. So we choose to take certain risks. That's okay; we're adults, we can make those choices for ourselves. But is it okay for us to play the odds for our babies?

That's the question parents have to ask themselves these days about phthalates and bisphenol-A in baby products. There's been a lot of media coverage recently, but the concern isn't new; scientists have worried for years about the health effects of these ubiquitous chemicals.

Phthalates are "plasticizers," chemicals added to plastic to make them more flexible and strong. They are found in all sorts of products, such as plastic wrap, pacifiers, shower curtains, plastic food storage containers, cleaning products, baby bottles, lotions, baby wipes, perfumes, raincoats, and garden hoses. They are not "chemically bound," so they leach out easily into fluids, onto skin, into the air.

Bisphenol-A is added to plastics to make them clear and shatterproof—which makes it an attractive ingredient for baby bottles and water bottles. It is also used to line cans and to make tableware, toys, food containers, and even some dental sealants.

Both phthalates and bisphenol-A have hormonal effects in rodents, interfering with normal growth and development. One study showed that phthalates have an effect on human development, but we don't know if it's an effect that makes a real difference in health or well-being. Both chemicals are linked to increased cancer risk in rodents—and bisphenol A caused behavioral changes in rodents as well.

I'm saying "in rodents" a lot, and that's because scientists tend to test potentially toxic chemicals on animals before they consider testing them in humans for obvious ethical reasons. And they tend to use high doses— those "rat levels" my father used to warn me about. Which begs the obvious question: does this data mean anything for humans? Does the fact that these chemicals are bad for rodents at high doses mean they will do anything to humans at low doses?

The answer is that we don't know. Studies are ongoing, but it may be years before we have answers. In the meantime, we need to make decisions for ourselves and for our children. Children, especially infants and toddlers, are at higher risk when it comes to environmental toxins. They are small, which means that small amounts of toxins can have bigger effects. Infants and toddlers put everything in their mouth, which increases their exposure. And children are still developing—meaning that a. they are at particular risk from anything that interferes with development, and b. toxic chemicals have years and years to cause problems, a particular concern with carcinogens.

So what should parents do while we wait for scientists to sort this out? There's no clear answer—for now, every family is going to have to figure out how they want to play the odds. Avoiding all phthalates and bisphenol-A is nearly impossible, but there are ways to lower exposure:

Look for phthalate- and bisphenol-A-free baby bottles, or use glass ones (with caution, obviously).
Use powdered formula instead of concentrate or ready-to-feed, which are sold in cans that may be lined with plastic containing bisphenol-A.

Look for phthalate-free ointments and personal care products. When you're home, consider using a washcloth instead of baby wipes.

Don't let your child suck or chew on plastic toys; if your baby uses a pacifier, make sure it's phthalate-free.
Look for toys made of wood or cloth (or, for older children, metal) instead of plastic.

Read the numbers on the bottom of your plastic products (the ones with triangles around them). 1,2,4 and 5 are better to use; avoid 3, 6, and 7. Avoid vinyl products, as well.

Rethink your plastic use in general. Use wax paper instead of plastic wrap, use things made of glass or ceramic for serving and storing food,

Use natural cleaning products. You can actually make your own from things like white vinegar, baking soda, and lemon juice; recipes are available at the Children's Health Environmental Coalition website.

Talk to your doctor—and read as much as you can, from reputable sources such as the Centers for Disease Control, the Environmental Protection Agency, and the National Institutes of Health. The more you know, the better odds player you'll be.



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