Researchers have conducted hundreds of studies of the potential health effects of exposure to bisphenol A (BPA), a chemical compound found in some plastic food containers, cash-register receipts and resin coatings in food-storage cans. Because it is a hormone mimic, a key concern is that exposure to BPA disrupts normal reproductive function. University of Illinois comparative biosciences professor Jodi Flaws recently co-wrote a review of the latest findings. She discussed the results with News Bureau life sciences editor Diana Yates.
Even after years of study, many of the findings on the effects of BPA on human reproductive health appear to be limited or inconclusive. Is there compelling evidence for any ill effects in humans?
Limited studies have been conducted in humans, but the studies that have been conducted consistently show, for example, that BPA reduces the quality of eggs in women undergoing in vitro fertilization procedures. A few human studies also suggest that BPA exposure may be associated with abnormal hormone levels in women and men. However, we need additional studies to examine the link between BPA exposure and adverse health outcomes in humans.
What are the most reliable findings to come from animal studies?
The most reliable findings in female animal models indicate that BPA exposure affects the development and function of the ovary. Specifically, it interferes with normal development of the eggs and normal production of hormones. BPA exposure also alters the function of the uterus by decreasing its ability to implant an embryo. The most reliable findings in male animal models indicate that BPA inhibits the ability of the testes to make sperm and to produce hormones. BPA exposure also may affect the development and function of the prostate.
Why is this subject so difficult to study?
The effects of BPA differ depending on the timing of exposure, the dose, the tissue/organ and species. This makes it very difficult to determine the exact effects of the chemical and to make general conclusions that apply to all exposure scenarios.
Are there other findings in humans that are worthy of attention?
Some studies suggest that BPA exposure is associated with polycystic ovarian syndrome in women and with infertility in women and men. These findings need to be verified in additional studies.
Where is the science inconclusive?
The science is inconclusive when it comes to determining the impact of BPA exposure on human reproductive outcomes. Very few studies have examined whether BPA exposure is associated with adverse reproductive outcomes in men and women. The science is also inconclusive when it comes to determining the mechanisms by which BPA causes reproductive toxicity in animal models. If we understand the underlying mechanisms of BPA toxicity, we might be able to develop ways to prevent or treat BPA-induced toxicity.
Do you have any advice for those concerned about exposure to BPA in their daily lives?
BPA is found in polycarbonate plastics, canned foods and as a coating on thermal receipt paper. Thus, those people who want to reduce their exposure to BPA can reduce their consumption of products in polycarbonate plastics and canned foods and minimize their exposure to thermal receipt paper.
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