A recent study funded by the National Toxicology Program and conducted by researchers with the Food and Drug Administration’s National Center for Toxicological Research has reportedly found no evidence linking low doses of bisphenol A (BPA) to adverse estrogenic effects in an animal model. K. Barry Delclos, et al., “Toxicity evaluation of Bisphenol A Administered by Gavage to sprague Dawley Rats From Gestation Day 6 Through Postnatal Day 90,” Toxi- cological Sciences, February 2014. To examine the effects of BPA on sprague Dawley rats shown to be sensitive to estrogenic compounds, scientists admin- istered the substance to rat dams from the sixth day of gestation through labor and to their pups from the first day after birth through postnatal day 90. These rats received either a low dose of BPA (2.5-2700 µg/kg bw/day) or a high dose (100,000 and 300,000 µg/kg bw/day), with the lower dose reportedly corresponding to approximately 70,000 times the amount ingested by a typical U.S. consumer. For comparison, the study included a naïve control group as well as a group that received two doses of ethinyl estradiol (ee2) “to demonstrate the estrogen responsiveness of the animal model.”
“Under the conditions of this study, BPA had clear adverse effects at doses of 100,000 and 300,000 µg/kg bw/day, with the majority of these effects observed in females,” noted the study’s authors. “In the study-defined ‘low BPA’ dose range of 2.5-2700 µg/kg bw/day, which was the primary focus of this study, potential effects could not clearly be linked to treatment as they were observed sporadically across the dose groups and did not occur in consistent grouping across organs as did effects of ee2 (0.5 and 5.0 µg/kg bw/day) or ‘high BPA’ (100,000 and 300,000 µg/kg bw/day).” See NPR’s The Salt, February 26, 2014.