In Wednesday’s post, I introduced the controversial issue of BPA and phthalates in children’s toys. This time, I’d like to explore the medical evidence regarding the chemicals’ effects on the developing human body, and take a look at what doctors have to say about the subject.
Last week, a report on BPA was issued by the National Toxicology Program, working under the National Institutes of Health and the U.S. Department of Health and Human Services. According to their report, BPA has the potential to effect human development and reproduction. BPA functions as a synthetic form of estrogen, and in studies on lab animals it was shown to reduce survival of newborn animals, lower birth weight, and slow growth of offspring early in life, and delay the onset of puberty in males and females. Although the doses given to the animals during the studies were much lower than the estimated levels to which babies and children are exposed, the report still cautions that “the possibility that bisphenol A may alter human development cannot be dismissed.”
Human studies of the effects of BPA remain inconclusive due to “small sample size, cross-sectional design, lack of large variations in exposure, or lack of adjustment for potential confounders.” In English, that basically means that we haven’t done enough in-vitro testing on human subjects to determine what the effects are, or how serious they might be.
As to whether or not the doses we take in are high enough to cause concern, the report concludes that “estimated exposures in pregnant women and fetuses, infants, and children are similar to levels of bisphenol A associated with several ‘low’ dose laboratory animal findings of effects on the brain and behavior, prostate and mammary gland development, and early onset of puberty in females.”
It’s no secret that girls are maturing faster today than in previous generations, with many girls developing breast buds as early as seven years of age and some developing as toddlers in more extreme cases, according to a report by the Breast Cancer Fund. One theory for this is that BPA levels in toys and plastic bottles leach the artificial estrogen compounds into their bodies from the time they are born.
As for phthalates, exposure to these chemicals is much more widespread, and the majority (over 90%) of Americans tested by the Center for Disease Control have shown metabolic evidence of multiple kinds of phthalates in their urine. The CDC issued a report in July 2005 that cited damage to the liver and testes and birth defefcts in rodents given high doses of phthalates, but concluded that further studies needed to be done to determine the risks to humans. In
addition, the doses given to the rodents in the study is much higher than the estimated average exposure rate for humans.
A separate 2005 study showed a link between phthalates and reproductive development in boys, citing a shortened distance between the anal and genital regions in boys born to mothers with high levels of phthalates measured in their urine during pregnancy. However, the National Toxicology Program questioned the science behind this study, stating that “Whether anogenital distance measurements in humans relate to clinically important outcomes, however, remains to be determined.”
So what does all of this mean? Basically, with both chemicals, there is evidence of effects on the human body, but not enough conclusive research to officially state that either chemical is highly toxic on a large scale. More testing needs to be done before we can fully determine how these chemicals could affect us.
That doesn’t mean that these chemicals are harmless, however, or that we shouldn’t be concerned, though. Dr. Maida Galvez, a pediatrician who has been studying the toxicity of BPA, had this to say when interviewed for ABC News: “We know the animal studies raise concerns, but there aren’t human studies showing effects yet … so, when we don’t have the evidence, what we recommend is that parents try to err on the side of caution.” She encourages parents to steer clear of products like containers and bottles in which BPA can leach directly into a child’s digestive system.
Medical evidence for the harmful effects of these chemicals has prompted several pieces of legislation both in the U.S. and abroad. We’ll take a look at the measures that government agencies have taken against BPA and phthalates in next Monday’s post.
