Are you using any canned food this Thanksgiving? Creamed corn? Canned pumpkin? Or maybe cream of mushroom soup for that old family favorite, the green bean casserole?
I hate to dampen anyone’s holiday spirits, but two new studies suggest that if you’re cooking with canned foods this weekend (or at any other time of the year), you’ll be ingesting something you hadn’t counted on: significant amounts of the toxic chemical bisphenol A (BPA).
In fact, one of the studies, published online Tuesday in the Journal of the American Medical Association (JAMA), found that eating a canned food item just once a day can increase your levels of BPA by more than 1,200 percent.
It’s not clear what that spike in BPA levels means in terms of health consequences, but the fact that it was so high raises concern.
As I’ve noted here before, BPA is a chemical compound used to make certain plastics and resins — including the epoxy resin that lines many metal-based food and beverage cans. Identified in laboratory studies as a hormone disruptor, BPA has been linked, mostly in animal studies, to a variety of medical conditions and brain-development problems, including cancer, heart disease, diabetes, obesity, early puberty, enlarged prostate glands, learning disabilities, hyperactivity and aggression.
More than 90 percent of Americans have detectable levels of BPA in their bodies at any given time, according to the Centers for Disease Control and Prevention. And much of that BPA enters our bodies by leaching into the canned food and drinks we consume.
Fresh vs. canned soup
For the JAMA study, a team of Harvard University researchers recruited 75 undergraduate and graduate students (median age 27), who were then randomly assigned to two groups. One group was served 12 ounces of a common brand of canned vegetarian soup for lunch for five straight days. (Each day featured a different “style” of vegetarian soup.) The other group was served a fresh vegetarian soup made without any canned ingredients. None of the participants were given any restrictions on the type of foods they could eat at other meals during the experiment.
After a two-day “washout” period (research suggests the human body tends to break down and excrete BPA within two days), the groups reversed their lunch fare. The “canned soup” group switched to fresh soup, and vice versa.
Urine samples taken during each week of the experiment found that BPA levels increased by 1,221 percent during the week that the participants had canned soup for lunch.
“The magnitude of the rise in urinary BPA we observed after just one serving of soup was unexpected and may be of concern among individuals who regularly consume foods from cans or drink several canned beverages daily,” said Karin Michels, senior author of the study and an associate professor of epidemiology at Harvard, in a prepared statement. “It may be advisable for manufacturers to consider eliminating BPA from can linings.”
Common Thanksgiving foods
The other study was released last week by the Breast Cancer Fund (BCF), which is a San Francisco-based nonprofit organization that focuses on environmental causes of breast cancer. The group has long advocated for removing BPA from all food packaging.
For the study, BCF researchers gathered four samples each of seven different types of canned food — including one set of samples collected here in Minnesota — and sent them to an independent laboratory in San Francisco to be tested for BPA.
The canned foods were ones that families frequently turn to at Thanksgiving: creamed corn, cranberry sauce, turkey gravy, green beans, cream of mushroom soup, pumpkin and evaporated milk (these last two for pie-making).
The study found that the BPA levels of the canned food varied widely — from non-detectable to 221 parts per billion (ppb) — even among samples of the same products. For example, a can of Campbell’s Turkey Gravy bought in New York was found to have 5 ppb of BPA, while the same product bought in Minnesota had 125 ppb.
But half of the cans had levels that have been linked in animal studies to adverse health effects, according to the authors of the report.
“We’re really concerned about pregnant women and young children,” said Kathleen Schuler, a senior policy analyst for the Minneapolis-based Institute for Agriculture and Trade Policy (IATP) and co-director of that organization’s Healthy Legacy project, which assisted the BCF in releasing the report. “Early life exposures [to BPA] are linked in animal studies to hormone disruption and very serious health effects later in life.”
A need for alternative packaging
Schuler, like the authors of the Harvard study, would like to see food companies find other, safer ways of protecting their canned food from bacterial contamination.
“There are a few manufacturers that have phased it out,” she noted. Eden Foods is one, she said, and Minnesota-based General Foods announced last year that it was switching to non-BPA packaging for its Muir Glen tomato-based products.
“I know that General Mills in general is looking at safer alternatives,” Schuler added. “They’re probably one of the companies that’s actually a leader on this, but we’d like to see that accelerated.”
Right now, BPA-free packaging is found only among more expensive brands — a factor that Schuler finds troubling. Many families, she noted, can’t afford those brands, and they may also have limited access to healthy alternatives, especially fresh produce.
“I’m really concerned about low-income communities,” said Schuler. “If somebody goes to a food shelf or if they don’t have a food co-op in their neighborhood so they have to shop at the supermarket and can only afford canned food, they may be getting a higher exposure [to BPA]. So there’s a social justice issue here as well.”
Schuler would like the government to become more pro-active about regulating the chemicals used in the processing and packaging of food.
“What we really need to do is review our regulatory system,” she said. “We need to reform the way chemicals are regulated through the Toxic Substances Control Act to prevent some of these chemical from getting [into the food supply] in the first place.”
“It’s not like the companies are trying to harm people,” she added. “It’s just the unintended consequences of normal industrial processes. We need to prevent that by upfront testing. We need to require companies to prove that these chemicals are safe.”
In the meantime, consumers — particularly pregnant women and young children — may want to minimize their exposure to canned products, she said.
To help you and your family go BPA-free this Thanksgiving, the BCF is offering some no-can recipes at its website.