BPA Hinders Learning, Memory, Study Shows
Chemical in common plastic products impairs synapse formation in brain
BY DEIRDRE HEALEY
The controversial chemical Bisphenol A (BPA) commonly found in hard plastic food and drink containers may impair the brain's ability to learn and remember, according to a groundbreaking study conducted by researchers at Guelph and Yale University.
The study reveals that continuous low doses of BPA hinder the formation of brain synapses, which allow neurons to communicate with one another and are critical to how we interpret and remember experiences.
“It dramatically impairs the formation of synapses in the regions of the brain important to learning,” says Prof. Neil MacLusky, chair of the Department of Biomedical Sciences. “These findings are worrisome because BPA is one of the most widely used chemicals in the world.”
BPA is used in plastic water bottles and some baby bottles, dental prostheses and sealants, and in the lining inside food cans. It's been proven that this chemical can leach from these products and be absorbed through human consumption.
Although previous research has been done on the harmful effects of BPA, MacLusky's study, published last week in the Proceedings of the National Academy of Sciences, is the first to mimic continuous environmental exposure levels.
Using the dose level declared safe by the U.S. Environmental Protection Agency for daily consumption by humans, the researchers exposed African green monkeys living on the Island of St. Kitts to BPA for a month.
Results showed that even at this low dose, BPA turns off increases in synapse density in the brain normally induced by estrogen, says MacLusky.
“Estrogen is more than just a female reproductive hormone. It enhances the rate at which some types of synapses are formed and is vital in maintaining normal neuronal structure in regions of the brain that control learning, memory and mood state. When we have BPA in our system, it seriously impairs this process.”
Although further research is needed, these results support the possibility that BPA is involved in human neurological conditions such as Alzheimer's disease, depression and schizophrenia, which all feature aberrant synapse formation and are also sensitive to sex hormone levels, he says.
This research was funded by the U.S. National Intitutes of Health and the Natural Sciences and Engineering Research Council of Canada.
Since hitting the news last week, this study has been covered by media outlets across Canada and around the world, including the Globe and Mail, National Post, Ottawa Citizen and Toronto Star, Canadian Press, GlobalTV and CTV News, the Washington Post, U.S. News, Britain's Medical News Today and the Times of India.