Canned soup manufacturers market their product as everything from a quick, nutritious meal for kids, to instant flavor for recipes, to an easy food option for dieters counting calories. But regular consumers of canned soups, and other canned products, could be paying for that convenience with their health.
A small study by the Harvard School of Public Health found regular consumption of canned soup may lead to an increase in levels of bisphenol A (BPA), an endocrine-disrupting chemical that has been linked to diabetes, obesity, cardiovascular disease, developmental deficits in children and an increased risk of breast and prostate cancer. BPA is used in the lining of metal food and beverage cans, and in the production of polycarbonate bottles (those with recycling number 7) and some dentistry composites and sealants.
"It's about canned foods."
Urine samples of volunteers who consumed 12 ounces of canned soup daily for five days revealed more than a 1,200 percent spike in BPA levels, compared to eating fresh soup. In a previous study on the consumption of beverages from polycarbonate bottles, lead author Jenny Carwile found a 66 percent increase in BPA among volunteers.
"We've known for a while that drinking beverages that have been stored in certain hard plastics can increase the amount of BPA in your body. This study suggests that canned foods may be an even greater concern, especially given their wide use," wrote Carwile, a doctoral student in the HSPH epidemiology department, in a university news release. He later told The Harvard Crimson: "This is not about the brand of canned soup. It's not even about canned soup. It's about canned foods."
"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. It may be advisable for manufacturers to consider eliminating BPA from can linings," senior author Karin Michels, an associate professor in the epidemiology department, said in the news release.
The researchers added that the elevated levels may be temporary and that more research is needed.
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In its September/October 2010 issue, Mother Jones magazine explained why BPA lines our canned food, what some state regulators are doing to change that, and what consumers can do to avoid BPA in canned products.
The magazine cites a 2009 study by Consumer Reports that tested the BPA levels of various canned goods, and found some levels especially high, even in organic brands. Significant levels were even found in products packaged in containers manufacturers said were BPA-free. Consumers Union, the publisher of Consumer Reports, recommends consuming no more than .0011 micrograms of BPA daily per pound of body weight.
Whole Foods Market says it is working with suppliers to eliminate the use of BPA in canned food, and 27 percent of the sales of Whole Foods' store brand canned good sales are currently of non-BPA cans.
And if all this information doesn't make you wring your hands, this should: A study by the Environmental Working Group found some cash register receipts contain BPA which could rub off on your hands. To remedy that problem, follow your mom's advice and always wash your hands before you eat.