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Bisphenol-A (BPA): Policies, Plastics, and Pregnancy

Renee Despres
Friday, June 15, 2012 - 20:32

Bisphenol-A (BPA) made headlines again on July 2, when California lawmakers voted to approve a bill that would ban the endocrine-disrupting chemical from food and beverage containers intended for children under three years of age. The bill passed only after a hot debate about the science behind bisphenol-A and its possible health hazards. With the bill, California became the eighth state to restrict or prohibit the use of BPA in food and beverage containers for young children. The California legislation regulating BPA in infant products is the most extensive of these laws.

For supporters of the bill, the fight was hard won. The bill was defeated last September by the lower house (although it passed the California Senate). And no wonder. Plastics and chemical manufacturers, as well as manufacturers and retailers of products that contain BPA (such as grocers) launched a massive campaign to squelch the bill. The San Francisco Chronicle reports that these trade groups spent a whopping $5 million fighting to keep BPA in babies’ products.

Why was it such a fight to pass a bill that seems a no-brainer – after all, what legislator wouldn’t want to come off as protecting infants’ and children’s health? While it’s easy enough to point fingers at industry, the truth is a little more complex. First, studies of BPA are limited and vary widely in quality, design, and outcomes. Second, BPA is used everywhere. And third, we love our plastics.

BPA is an industrial chemical used to make polycarbonate plastic and epoxy resins. BPA was first synthesized in 1891. During the 1930s, it was used as a synthetic estrogen. A few years later, chemists discovered that when BPA is combined with phosgene (used during World War I as a toxic gas) and a few other chemicals, it yields polycarbonate plastic. Suddenly, a whole world of useful, relatively inexpensive products were possible. Nalgene bottles, baby bottles, bulletproof glass, shatterproof eyeglasses, and much, much more.

Commercial use of BPA began in the 1950s and grew rapidly – as did our love for those useful, clear, shatterproof, cheap, lightweight, polycarbonate plastics. By in 2003, approximately 3 million metric tons of BPA was manufactured globally. The Bisphenol-A website, developed by the American Chemistry Council (whose members are those manufacturers of the plastics you use and love every day) reminds us that BPA is “used in countless applications that make our lives easier, healthier and safer, each and every day.” BPA-containing plastics are everywhere, and they’re an easy, attractive alternative to breakable glass or weighty metals, especially when there’s a curious infant or toddler in the house.

During the manufacturing process, most of the BPA is locked into chemical bonds in the plastic. But some of doesn’t bond with other molecules in the plastic and can escape, especially if that plastic is heated (ever put a baby bottle in the dishwasher? Heated up a bowl of food in a plastic microwave container?). And that escaping BPA has some scientists concerned.

Their concern is based on the potential for BPA to interact with substances produced by the body. BPA is one of several widely-used substances that are classified as “endocrine disrupting chemicals.” Endocrine-disrupting chemicals interfere with the way the body makes, processes, and uses hormones – the “messenger” molecules that regulate almost all functions in the body. Disruptions in hormone activity can have tremendous effects on both humans and wildlife, leading to cancers, infertility, neurological problems, problems with the immune system, and more.

Evidence is accumulating that BPA may have long-lasting negative effects on the body. Studies that have examined the effects of BPA, both in laboratory animals and in humans, have raised disturbing questions about the effects of the chemical on human and animal health. Most of these studies have been in animal models, but a growing number have looked at human exposures to BPA and their potential health effects. BPA exposure has been linked to multiple problems, including childhood obesity, breast cancer, early puberty, reproductive problems, and neurological and behavioral problems including autism, attention deficit disorder, and hyperactivity.

The California bill responds to many of these concerns, but it misses a key component of reducing infants’ and children’s exposure to BPA: prenatal exposure to the chemical. Infants and children, with their tiny sizes and fast metabolisms, are more vulnerable to the effects of BPA (and just about any other chemical you can think of). But that vulnerability begins way before Momma pops the first baby bottle into that little mouth. It begins in the womb, with maternal exposure to the chemical, and continues after birth. BPA is found in breastmilk, so if Mom is drinking out an old Nalgene bottle that’s been run through the dishwasher, so is baby.

Geneticist Patricia Hunt sounded the first alarm about prenatal exposure to BPA more than a decade ago, when 40 percent of her laboratory mice developed egg defects after a janitor cleaned their cages and water bottles with an abrasive cleanser – releasing BPA. Since then, multiple studies have probed the health effects of maternal exposure to BPA on both male and female offspring.

Since Hunt’s initial findings, more than 500 studies the impact of prenatal exposure to BPA on offsprings’ health have been published. These include the impact on both males – for example, in a paper presented yesterday at the 92nd Annual Meeting of the Endocrine Society, researchers from Auburn University reported that prenatal exposure to low levels of BPA was linked with low testicular function in adult males.

A second study , published in Hormones & Cancer this past June, bears a little more discussion here, because it demonstrates the complexity of addressing BPA as a public health problem. In this study, researchers found that women whose mothers had been exposed to bisphenol-A (BPA) and/or another endocrine-disrupting chemical (diethylstilbestrol [DES]) during pregnancy were at increased risk of developing breast cancer.

A comparison between DES and BPA is illustrative. DES is a synthetic estrogen that, like BPA, was once used to artificially increase women’s estrogen levels. Between 1938 and 1971, between 5 and 10 million women and their offspring were exposed to DES. In 1971, the U.S. Food and Drug Administration (FDA) advised physicians to stop prescribing DES to pregnant women. Evidence of the health risks of DES was clear and showed that 1) daughters of women exposed to DES during pregnancy were at increased risk of breast cancer, multiple reproductive problems, and cervical and vaginal cancer; and 2) sons born to those women were at increased risk of non-cancerous epididymeal cysts.

The public health solution for DES was simple: Stop prescribing it. But BPA is a much more complex public health problem. First, we still don’t know the health effects of BPA, if it’s harmful for everyone, or just how harmful it might be. So it’s difficult to justify the expense of revamping multiple industries to eliminate it.

Second, BPA is ubiquitous. It’s found in everything from the plastics that line the insides of food cans and water pipes, hard plastic dental fillings, baby bottles, water bottles, plastic containers where we store our foods, sunglasses, medical devices, sports equipment, electronic equipment, automobile parts, construction glazing… the list goes on. Most people have been exposed to it, even in the developing world. Unlike DES, we can’t eliminate exposure to BPA simply by asking doctors to stop prescribing it. BPA can be detected in the urine of more than 93 percent of the U.S. population ages 6 and older, according to data from the 2003-2004 National Health and Nutrition Examination Survey (NHANES).

The California law is a good step. But if we are really going to eliminate our children’s exposure to BPA, we need to include the exposure they receive while still in the womb. To develop good health policies regarding BPA, we need to know much more about the chemical and its health effects. We need more information about how humans are exposed to BPA. We need to know how the metabolism of BPA differs between laboratory animals such as mice, non-human primates, and humans, and how it varies with age. We need the tools to evaluate the outcomes of existing studies, which involve widely varying methods and doses. And we need more studies, especially in humans. Once we have that information, it needs to be communicated effectively, so people can weigh the risks and benefits of using BPA-containing products. Then we can ask lawmakers to develop the policies we need to protect ourselves.

In the meantime, legislators and laboratories aside, you can reduce your family’s exposure to BPA. Here are a few ways to minimize BPA exposure.

  • Use glass, stainless steel, (lead-free) ceramic, or porcelain containers, especially for hot foods.
  • Minimize your use of canned foods. Fresh, frozen, and dried are all good alternatives (but store them in metal or glass containers, not plastics).
  • Avoid plastics marked with the recycling number “7,” which indicates BPA has been used.
  • When you do choose plastics, use BPA-free plastics. But remember the chemicals used to replace BPA may have even less of a safety record.
  • Heat causes BPA to leach out of plastics. Never mix heat, plastics, and food — that includes microwaves and dishwashers.