Features
Babies Have 11 Times More Bisphenol A in Their Bodies
Than Adults Do, Study Finds
U of G toxicologist advises pregnant women to reduce or eliminate exposure to banned substance
BY ANDREW VOWLES
As a mom, Andrea Edginton recalls it was an easy choice. Her son was about 12 months old when she pitched his feeding bottles last year and bought new ones, following Health Canada's announcement of plans to ban plastic bottles containing the chemical bisphenol A (BPA).
Edginton's son is now almost two years old and still BPA-free. Recalling her decision, she says: “The alternatives are there, so why not use them?” But as a scientist who studies how the body gets rid of substances, she had lingering questions. What exactly was the problem with BPA in newborns and youngsters?
“I researched a bit and thought: Let's figure out why I did switch the bottles,” says Edginton, a two-time Guelph graduate who last year joined the faculty at the University of Waterloo's pharmacy school.
Figuring it out led her back to Guelph's Department of Environmental Biology, where she had studied environmental toxicology. There she found Prof. Len Ritter, who studies human health aspects of toxicology.
Their result?
“Mom's” instincts had been correct. They found that, compared with adults, newborns and infants may have up to 11 times as much BPA — reported to be linked to cancer and reproductive and behavioural problems — in their bodies.
Their study appeared late last year in Environmental Health Perspectives, published by the National Institute of Environmental Health Sciences in the United States. The paper, listing Edginton as senior author, supports Ottawa's move to ban the substance in plastic baby bottles and suggests the industry look for replacement products.
“I would advise a pregnant woman to try to reduce or entirely eliminate her exposure to bisphenol A,” says Ritter, who is executive director of the Canadian Network of Toxicology Centres based at U of G.
BPA is found in many everyday products, including baby bottles, liquid formula containers and food cans, as well as reusable water bottles. The substance can leach from containers and be ingested.
Reports have suggested that exposure to BPA can interfere with the normal working of hormones in people and animals. Earlier studies have linked low BPA exposure to cancer, early onset of female sexual maturity, male fertility problems, impaired learning and behavioural problems such as aggressiveness.
Exposure to current levels of the substance does not appear to pose a health risk for most Canadians, but children and infants are considered to be more vulnerable than adults.
Ritter and Edginton used data from adult human and animal studies to estimate how long BPA stays in a baby's body. Their mathematical model includes information about key enzymes that break down the chemical in the body.
Those enzymes are found in much lower amounts at birth than in grownups. Assuming that BPA exposure is identical between babies and adults, the amount in a baby's blood is about 11 times higher than in an adult, says Ritter.
Confirming their results, another Environmental Health Perspectives study published last year using human subjects found that BPA levels in children were 10 times higher than in adults.
“It was exactly what we had predicted,” says Ritter. “Governments need to move quickly to reduce or eliminate exposure as much as possible, especially in sensitive populations. And industry needs to develop alternatives. The target, especially in sensitive populations, is zero.”
Health Canada is currently writing regulations to ban polycarbonate baby bottles containing BPA. Canada is the first country to move to ban the substance in these containers.
Edginton says regulators need to account for physical differences between adults and youngsters in setting standards for substances in blood plasma. She will speak in March at a panel in Germany, where regulators are proposing to follow Canada's lead on banning BPA.
For her PhD at Guelph, she studied the effects of herbicides on frogs.