Consumers wary of the dangers of bisphenol A (BPA) are cautious to avoid the endocrine-disrupting chemical. And in recent years some food companies have responded by eliminating it from their packaging. However, it appears more work needs to be done to keep it out of the human body.
That’s because scientists have developed more accurate measuring of BPA levels and it shows exposure is far higher than previously thought.
Researchers at Washington State University, the University of California at San Francisco (UCSF) and the University of Missouri published their findings in the journal Lancet Diabetes & Endocrinology. They explained how measurements relied upon by regulatory agencies such as the U.S. Food and Drug Administration (FDA) are inaccurate. They said the exposure levels have been underestimated by as much as 44 times.
"This study raises serious concerns about whether we've been careful enough about the safety of this chemical," said Patricia Hunt, Washington State University professor and corresponding author on the paper. "What it comes down to is that the conclusions federal agencies have come to about how to regulate BPA may have been based on inaccurate measurements."
BPA is found mainly in plastic packaging such as food and drink containers. It has been shown in studies to interfere with hormones and fetal exposure has been linked to a wide range of health problems related to growth, metabolism, behavior, fertility and even cancer.
The FDA has relied on previous studies and determined human exposure to the chemical is very low and considered to be within safe levels. Researchers at Washington State believe the previous method of indirectly measuring BPA is inaccurate and also calls into question the levels of other chemicals previously thought to be at safe levels.
UCSF researcher Roy Gerona developed a direct way of measuring BPA that is more accurate. Both methods rely on testing human urine for levels of BPA metabolites, the compounds created as the chemical passes through the body.
The old way relied on an enzyme solution made from a snail that transformed the metabolites back into whole BPA so it could be measured. The new method gives researchers the ability to directly measure the metabolites without the enzyme solution.
The research team compared the methods by testing synthetic urine spiked with BPA and 39 human samples. The direct method of testing yielded results of exposure as much as 44 times the mean reported by the National Health and Nutrition Examination Survey (NHANES). They also found the greater the level of BPA exposure the greater the disparity in old and new testing results.
"I hope this study will bring attention to the methodology used to measure BPA, and that other experts and labs will take a closer look at and assess independently what is happening," Gerona. "BPA is still being measured indirectly through NHANES, and it's not the only endocrine-disrupting chemical being measured this way," Gerona said. "Our hypothesis now is that if this is true for BPA, it could be true for all the other chemicals that are measured indirectly."