Canned chemicals

As state delays food labels, there’s even more reason to be aware of BPA

Bisphenol A is a carcinogenic chemical used in many plastics and the lining of canned food.

Bisphenol A is a carcinogenic chemical used in many plastics and the lining of canned food.

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It was originally published online by Environmental Health News at

It’s no secret. For some time, California has officially recognized that bisphenol A is harmful to human health. In 2011, Gov. Jerry Brown signed a bill to ban BPA from baby bottles and sippy cups. Last year, the state added BPA to its list of known harmful chemicals under Proposition 65, the Safe Drinking Water and Toxic Enforcement Act of 1986.

The chemical is used in many plastics—including food and drink containers—and exposure to it has been linked to disruptions in the body’s reproductive system and increased risk of cancer, among other conditions.

Even so, it will be some time in California before warning labels appear on grocery store products containing BPA. As required by Prop. 65, the state’s Office of Environmental Health Hazard Assessment had planned to roll out such labels in May, but opted instead for a general notice—a 5-by-5-inch warning sign about the harmful effects of BPA posted at grocery store checkout lines. It warns consumers that jar lids and bottle caps may contain the carcinogen. It reads: “You can be exposed to BPA when you consume foods or beverages packaged in these containers.”

It’s a temporary measure. The state needs a year or so to figure out which products containing the chemical need that type of warning on the label, according to

Meanwhile, new research has found another reason to be wary of BPA. Children in the U.S. with higher levels of BPA in their bodies are more likely to have ADHD, according to a recent study.

The nationwide study of 460 children ages 8 to 15 found that 11 percent of children with BPA levels higher than the median level had ADHD. In contrast, 3 percent of those children with BPA levels below the median had ADHD.

The research, published online in the Environment Research journal, adds to evidence that BPA exposure may alter children’s brain development and lead to behavioral problems such as reduced attention and hyperactivity.

ADHD is the most common behavior disorder among children in the U.S. It’s unclear what causes the disorder, but research suggests a mix of genetics and exposure to some environmental chemicals, such as BPA, which is known to disrupt hormones.

The association demonstrated in the study was stronger for boys than girls, which reflects broader ADHD trends. Nationally, about 10 percent of children between 5 and 17 have had an ADHD diagnosis, with boys having a significantly higher rate, at 14 percent. By comparison, about 6 percent of girls have the disorder, according to the U.S. Centers for Disease Control and Prevention.

“You’d expect to see differences between the two sexes,” said Laura Vandenberg, an assistant professor of environmental health at the University of Massachusetts, Amherst, who was not involved in the study. BPA mimics estrogen hormones. The sexes use hormones differently to influence brain function.

Overall, boys seem to have a higher risk for neurological problems, and “we’re not entirely sure why that is, said Sarah Evans, an instructor at the Icahn School of Medicine at Mount Sinai in New York, who also was not involved in the research. “It’s possible the male brain is maybe more vulnerable to environmental exposures.”

BPA is used to make plastic hard and shatterproof and to extend the shelf life of canned goods. It can leach out of can linings and into food. Studies show that just about everyone has traces of the chemical in their body. For instance, 97 percent of the children who participated in the recent study had BPA in their urine.

The additive has been linked to multiple health impacts in exposed babies and children—including obesity, asthma, low birth weights and genital defects.

A 2014 study on prenatal exposure to BPA found higher levels meant more behavior problems for school-age boys. Evans, lead author of that study, said prenatal exposure to chemicals is a “window of high susceptibility,” but so are the childhood years. The brain keeps developing into the 20s.

Research specifically looking at hyperactivity disorders and BPA exposure has been mixed, with some finding a link and some not. Most of the previous studies, however, have been on children younger than 8 years old, and the symptoms of ADHD often manifest later than that.

“It’s hard to get an idea whether preschoolers have ADHD or not, as it’s normal for preschoolers to have behaviors that in an older child would raise concerns about ADHD,” said Dr. Tanya Froehlich, senior author of the new study and a developmental-behavioral pediatrician in Cincinnati.

Animal studies show that BPA may alter the body’s levels of dopamine—a chemical messenger that helps people think and stay alert and focused. “Dopamine systems are modulated by estrogen and BPA is a synthetic estrogen,” Froehlich said.

There are also indications that BPA can negatively interact with thyroid hormones—“critical in normal brain development,” Evans said.

The study was limited in that the researchers used a single urine test to determine exposure, as BPA is quickly eliminated from the body, and they don’t know what the children’s prenatal or early childhood exposure to the chemical was. “We’d really like to see levels of BPA exposure over time and how they correlate with risk to ADHD; we had this single snapshot with their levels at the time of the study,” Froelich said.

It’s also possible that kids with ADHD happen to have different eating habits and children with hyperactive behavior are eating poor foods with more BPA contamination, Vandenberg said.