If you attended class today, you’ll know that we discussed the issue of bisphenol-A (BPA) in food packaging and plastic bottles/containers. It was concluded that the study featured in the article we read only actually tested whether eating canned soup causes BPA levels in humans to rise, NOT the affect, if any, BPA has on human health (despite the author talking about it in the write-up.) This left me wondering, what actually are the effects of BPA on human health, and should I be concerned about it? I headed to the internet in search of the facts.

What is it?

Bisphenol-A (BPA) is a chemical used for its qualities of durableness and impact resistance in plastics such as beverage containers, toys, car parts, CDs, food packaging, and many other frequently-used objects. BPA was first used commercially in the 1950s, and it it still used heavily worldwide with an estimate of 2.2 metric tons being created each year.

Why should we be worrying about it?

In a 2008 study from the CDC of over 2,500 U.S. citizens, it was discovered that 93% of participants had detectable levels of BPA found in their urine samples. With BPA being such an omnipresent part of consumer products, many are concerned about the potential health effects, but what those are exactly is still unclear.  Despite this, the Environmental Protection Agency currently recommends a tolerable daily intake (TDI) of BPA as 50 μg/kg/day. In 2012 and 2013, the U.S. Food and Drug Administration banned the use of BPA in baby bottles and other infant food packaging/ containers due to public concern and uncertainty on the effects of BPA, however the ban has since been lifted because producers of such goods have stopped using BPA. A fact sheet from the U.S. Center for Disease Control simply says, “Human health effects from BPA at low environmental exposures are unknown. BPA has been shown to affect the reproductive systems of laboratory animals. More research is needed to understand the human health effects of exposure to BPA.”

What does the research say?

BPA is known as an endocrine disruptor, which means it can interfere with hormones found in the human body. In 2013, the journal Reproductive Toxicology published a meta-analysis of 91 studies on BPA and human health. The analysis found that in 70% of the studies, “significant adverse effects” were found in averagely-exposed populations. A total of 16 of the studies found that BPA had no effects on the factors in question.  Factors studied included fertility, infant developmental effects, metabolic disease, and others. The meta-analysis found the following: “strong evidence that adult exposure to BPA is associated with cardiovascular diseases and adverse cardiovascular health, in many populations,” “on the whole… the studies strongly suggest that BPA is associated with neurobehavioral problems in children,” “there is some evidence that BPA may contribute to infertility in humans,” among others. Some rumored effects of BPA, however, were invalidated, such as: “a link between BPA and breast cancer cannot be determined”, and “…the literature does not support a clear-cut link between prenatal BPA exposure and altered birth weight of the offspring.” The analysis clearly listed many correlations between BPA and negative human health effects that were found to be significant, but also listed several cases in which no correlation was found between BPA level and human health. The comprehensive study concluded with data from several studies in which participants (men, women, and children) exposed to much lower BPA levels than the nationally recommended amount of 50 μg/kg/day had shown “significant” adverse health effects. Although it is unclear to me exactly what “significant” means, this knowledge suggests that perhaps that recommendation level should be reevaluated, in the interest of public safety.

On the other hand, some scientists argue that BPA does not pose significant health risks. In a 2012 NPR feature, senior research scientist Justin Teeguarden from the Pacific Northwest National Lab stated that the human body can “inactivate dangerous chemicals like BPA in the intestine and liver”, rendering the trace amounts that make it into the body harmless.

Research chemist Dan Doerge completed studies in infant monkeys, mice, and rats to see if newborns were able to deactivate BPA as well as adults. He found that monkeys had ten times less toxic BPA in their bloodstreams that the mice or the rats, because they have better metabolic ability to detoxify the chemical. Because of this, Doerge argues that since humans are similar to monkeys than rodents, we should also have this increased ability to detoxify BPA.

Conclusion:

With conflicting opinions within the scientific community, clearly more research needs to be done on the subject of BPA and its effects on human health. There are many studies that show negative effects due to BPA, but is the exposure level high enough to be of concern to the public? More large-population, long-term studies should be carried out in order to have more complete information on the issue. In the mean time, it is up to individual consumers to decide if the exposure is worth the possible risks to themselves. Many products are now labeled if they are BPA-free, and consumers can choose alternatives to plastic bottles and canned foods. We will hopefully hear more about this issue in the future.