News Stories Archive | Page 10 of 11 | Facts About BPA

USA Today reporter Liz Szabo has long rung the alarm bells on bisphenol A (BPA), devoting an entire full page article to promoting the repeatedly discredited claims of University of Missouri researcher Frederick vom Saal. Now, she has turned to vom Saal’s longtime collaborator, University of Tufts researcher Ana Soto to advance the claim BPA increased the risk of mammary cancers in rats and therefore might pose a risk to humans.

That question is particularly relevant this week in light of numerous media articles reporting that exposure to a common chemical is linked to obesity in children and adolescents.  Underlying the articles is a new study on bisphenol A (BPA) published this week in Pediatrics.  The key question is that of causation versus statistical association. The new study is a cross-sectional epidemiology study in which the data analyzed is all collected at the same time.  The data are from the NHANES (National Health and Nutrition Examination Survey) database, which collects extensive health and nutrition information on a nationally representative sample of about 5,000 people each and every year.  Also collected is biomonitoring data from analysis of blood or urine samples for more than 300 chemicals, including BPA.  To be more precise, the analysis measures metabolites of BPA, the significance of which is discussed below.

Furthermore, it may alert us to the danger when a paper deals with a topic that has received enormous publicity and caused public alarm, as is the case with BPA.  This may have lowered the threshold for publication.  In other words, to the extent that the reviewers and editor were aware that the paper was weak and its results dubious, they may have over-ridden these reservations on the grounds that the paper was on a topic of great interest.  Finally, publication of this paper may be symptomatic of a lower level of scientific rigor and overall quality prevailing in the area of environmental health, an area where there is great public and media interest, as opposed to other research areas that do not evoke so much interest.

Using vegetables canned at their peak freshness can be a way to enjoy your favourite produce out of season, but most of them will be in cans lined with BPA. There are growing concerns about Bisphenol A's estrogenic properties, and it was recently found that most Canadians have BPA in their blood. Avoid it by using frozen veggies instead.

Last week, a study published in the journal Human Reproduction reported that bisphenol-A (BPA), a compound widely used to make polycarbonate plastic and epoxy resins, altered maturation of human oocytes in vitro.  Specifically, at high concentrations of BPA, oocyte maturation decreased while the incidence of oocyte degeneration increased. In an accompanying press release, the authors suggested that BPA “may cause a significant disruption to the fundamentals of the human reproductive process and may play a role in human infertility.” 

FDA acknowledges the interest that many consumers have in BPA. FDA has performed extensive research and reviewed hundreds of studies about BPA’s safety. We reassure consumers that current approved uses of BPA in food containers and packaging are safe. Additional research is underway to enhance our understanding of BPA. FDA will take these studies into account as it continues to ensure the safe use of BPA in food packaging.

“Chemical” is not a dirty word. Nor is it a synonym for “poison” or “toxin.” Chemicals are the basic building blocks of all matter and classifying them as “safe” or “dangerous” is inappropriate. But of course there are safe or dangerous ways of using chemicals. In any case, chemicals are not to be feared or worshipped, they are to be understood. And perhaps the most important point to understand is that the presence of a chemical does not equate to the presence of a risk.

Thanks to our analytical capabilities, we can now routinely detect substances down to the part per trillion (ppt) level. That’s not finding a needle in a haystack; it’s finding a needle in a world full of haystacks. At that level, we can detect a myriad of chemicals should we choose to look for them! And by selectively referencing the scientific literature, the spectra of risk can be readily raised.

Forbes interviewed Professor Richard Sharpe, a leading expert on male reproductive health, who is directing a research team at the UK’s Medical Research Council (MRC) Centre for Reproductive Health at the University of Edinburgh in Scotland. Sharpe argues that the controversy on BPA stems not in the in chemical posing a threat, but in the refusal of a small group of scientists to accept that their basic research, consisting of small studies with questionable methodologies and limited statistical power, could not be replicated by much larger studies using larger sample sizes and more sophisticated and careful methods.

Toxicologist Justin Teeguarden’s investigation of 150 studies on BPA, which included 30,000 people in 19 countries, including infants and children, concluded that concentrations of BPA in the blood were not high enough to result in “estrogenic” activity, as some other scientists claimed. When BPA is taken in orally, it is rapidly converted to a substance with no known biological activity as it is absorbed into the body, leaving very little BPA to enter the bloodstream. Professor Richard Sharpe of the Medical Research Council’s Centre for Reproductive Health in Edinburgh also cast doubt on studies linking BPA to obesity at the American Association for the Advancement of Science (AAAS) conference where Teeguarden presented his findings.

BPA in the blood of the general population is many times lower than blood levels that consistently cause toxicity in animals, according to a meta-analysis of almost 150 BPA exposure studies by toxicologist Justin Teeguarden of the Department of Energy's Pacific Northwest National Laboratory, Richland, Wash. According to Teegauarden, people's exposure may be many times too low for BPA to effectively mimic estrogen in the human body. His analysis was presented at an annual meeting of the American Association for the Advancement of Science.