Study Links BPA to Lower Thyroid Function
French researchers say they have uncovered new risks
Sunday, November 18, 2012
Ever since a study showed bisphenol A (BPA), a major molecule used in the plastic industry, was an endocrine disruptor that could exert negative effects on human health, it has been the focus of even more health studies.
The latest, by researchers in France, has found that an unborn child exposed to BPA can be at increased risk of lowered thyroid function. The findings are based on a study of newborn sheep.
Hypothyroidism is characterized by poor mental and physical performance in human adults and in children can result in cognitive impairment and failure to grow normally.
A new direction
The French study is actually a departure from more recent investigations, that have focused on reproductive functions. It points to evidence that BPA might have negative effects on other endocrine systems including thyroid function.
The current study used sheep, which researchers said was a relevant model for human pregnancy and thyroid regulation and ontogeny. It analyzed the internal exposures of the fetuses and their mothers to BPA and determined to what extent those exposures may be associated with thyroid disruption.
“Our study is the first to show that BPA can alter thyroid function of pregnant animals and their offspring in a long-gestation species with similar regulation of thyroid function as humans,” said Catherine Viguié, PhD, of Toxalim, Research Centre in Food Toxicology in Toulouse, France and lead author of the study.
Because of the potential consequences of maternal/fetal thyroid disruption on neural and cognitive development, Viguié thinks her study warrants the need for further investigations on the effect of BPA on thyroid function.
Though BPA once was in nearly every kind of plastic container, it's being found in fewer these days. In the wake of studies raising health questions, many manufacturers have eliminated their use of the substance, even though the food industry continues to back it.
Most recently many beverage companies have begun using plastic bottles made without BPA, which is a hardening agent. Other manufacturers have also removed it from many brands of infant formula bottles.
Most of the recent studies point to BPA’s ability to interfere with the body’s hormone system, potentially leading to a variety of health problems, including damage to the reproductive system and the brain, particularly in children. Eleven states have banned the chemical’s use in certain products, typically baby bottles and other children’s goods; Canada, China and the European Union have similar restrictions.
An industry group, the American Chemistry Council, says BPA has been used safely for decades and there is no evidence that it causes harm as it is currently used. A key component of many plastic products, BPA is found in everything from the lining of food cans to the paper used in store receipts.