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Why you may want to avoid canned food this Thanksgiving

Cranberries in their natural state, jelled and in a can
CC/Flickr/Purple Slog
Cranberries in their natural state, jelled and in a can.

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.

Kathleen Schuler
Kathleen Schuler

“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.

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Comments (5)

  1. Submitted by Bill Gleason on 11/23/2011 - 10:10 am.

    Very good article.

    I would emphasize here, though, right up front that it is the can linings that are responsible. Although this is in the article, it is the take home message that the average consumer should be made aware of.

    I first noticed these plastic linings in cans of tomato based products that are acidic. They got the bright idea of making the linings white so that they would be obvious. I hope the white color is not due to TiO2 – that would be another bad idea.

    It should be noted that including BPA in the canning process is a relatively new development and obviously should be reversible.

    BPA and estrogen/androgen mimicking phthalate esters have been known as problems for some time. Too bad that this late in the game people are finally becoming aware of their dangers.

    And some folks want to do away with the EPA/FDA. God help us.

  2. Submitted by Ray Schoch on 11/23/2011 - 11:04 am.

    “…And some folks want to do away with the EPA/FDA. God help us.” Indeed. That said, however, I don’t see any change on the horizon regarding my belief that jellied and canned IS the “natural state” of the cranberry…

    As a consumer, I certainly hope General Mills’ example is, as you say, “accelerated.” I’d especially like to see it accelerated for brands and foods that are not typically high-end products. I don’t know many people who are eager to revert to the common winter diet of the mid-19th century, when Minnesota was being settled. My own tolerance for root vegetables and dried fruit to ward off scurvy is fairly low.

  3. Submitted by Ray Marshall on 11/23/2011 - 07:26 pm.

    This article brings back very fond memories of the beginning of the “You’re all going to die if you eat this movement.”

    About 1957-8, I was the president of the Eager Eaters [I wasn’t the most popular, I was the fattest] club at my high school, a bunch of nerds who sat together each day at lunch.

    That Thanksgiving the newspapers were filled with stories about how we were all going to die if we ate cranberries. A closer examination of the articles in the newspapers showed that if we ate three cans of cranberries a day for 13 years there was a 23% probability that we would get cancer.

    The cranberry growers of Massachusetts and Wisconsin (it’s always puzzled me why cranberries grow in no other states than those two) were aghast at this attack on their livelihoods.

    I don’t believe that anyone ever died from eating cranberries. But I do believe that this was the first “food scare” to hit the U.S. media. And from this article today on Minn Post, food scare articles are still with us.

  4. Submitted by Carol Koepp on 11/24/2011 - 12:41 pm.

    Other research that relates to this article was printed in the August 2010 issue of Environmental Health Perspectives and in the January 2007 issue of Environmental Research.

    In a cohort study by Joe Braun, MSPH, PhD Dept. Environmental Health, Harvard School of Public Health and published in the Dec. 2009 issue of Environmental Health Perspectives, it was found that gestational BPA exposure was linked with increased hyperactivity and agression scores in girls at age 2.

    At age 3 increased depressive and anxiety symptoms in girls was linked and increased when there was gestational exposure to BPA

  5. Submitted by Bill Gleason on 11/26/2011 - 10:30 am.


    No one ever died from eating cranberries.

    This is the kind of blow-off of serious problems often perpetrated by the right.

    At least ten years ago, before all the fuss about phthalate esters and BPA I stumbled on a paper that showed that the serum concentration of these compounds in Puerto Rican girls was the highest in the US. These are estrogen mimicks. It also noted that premature onset of menarche was a big problem there…

    For a general intro see: http://bit.ly/uVLGPH and check out links.

    It disappoints me very much that people will try to blow off these types of problems by implying that they are comparable to the danger of eating 13,000 cans of cranberries…

    Do you realize how ridiculous this looks, Mr. Marshall?

    William B. Gleason, Ph.D.
    Associate Professor
    University of Minnesota Medical School

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