The two separate developments came as the US Food and Drug Administration (FDA) continued to delay delivering its decision on the safety of the substance that is used in food packaging such as polycarbonate bottles and the epoxy linings of food cans.
A study by the French National Institute of Agronomic Research (INRA) found BPA caused a negative reaction in the intestine of rats – even at low doses. The report was published in the Proceedings of the National Academy Sciences and focused on the digestive tract as the first organ the chemical comes into contact with after being consumed.
INRA said its team orally administered doses of BPA to the rats that were equivalent to about 10 times less than the daily amount considered safe for humans. The Toulouse-based body’s research was also carried out on human intestine cells and revealed the chemical lowered the permeability of the intestines and the immune system's response to digestive inflammation. They also found that newborn rats exposed to BPA in the uterus and during feeding have a higher risk of developing severe intestinal inflammation in adulthood.
“These findings illustrate the intestine's great sensitivity to Bisphenol A and open new research paths for characterising and evaluating the effects of endocrine disruptors from food,” said a statement from the researchers.
It added: “They may also contribute to risk assessment and the determination of new acceptable exposure thresholds for these molecules.”
Concern about the substance grew further when the director of the National Institute of Environmental Health Sciences (NIEHS) and the National Toxicology Program warned people - particularly pregnant women and children - not to consume the substance.
Linda Birnbaum told the Milwaukee Journal Sentinel that people should be worried about BPA and should avoid it where possible. While admitting she was not a qualified doctor, the federal official said numerous studies on the chemical had made her concerned about its health effects.
"It's simple enough to avoid," she said. "So, why not avoid a problem?"
The NIEHS has recently launched a $30m research programme to investigate the effects of BPA.
Consumer anxiety about BPA continues to increase even though the FDA and the European Food Safety Authority maintain the chemical is safe for use in food packaging. The FDA was scheduled to deliver a review on the chemical by the 30 November but failed to meet its own deadline. The body has refused to give a reason for the delay or provide a new date for publication.