(CBS) Talk about stirring up controversy. A new study shows that the urine of people who consume canned soup can contain surprisingly high levels of bisphenol A (BPA), a hormone-disrupting compound linked to health problems including heart disease, diabetes, and obesity.
People who consumed one serving of canned soup a day for five days had a more than 1,000 percent increase in urinary BPA over people who consumed fresh soup for five days, the study showed.
"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," study author Jenny Carwile, a doctoral student at Harvard School of Public Health, said in a written statement. "This study suggests that canned foods may be an even greater concern, especially given their wide use."
BPA is used in the linings of metal food and beverage cans as well as in certain plastic bottles and dental sealants.
Seventy-five volunteers were recruited for the study. Every day for five days, one group consumed 12 ounces of canned vegetarian soup and another consumed 12 ounces of fresh vegetarian soup. After a two-day "washout period," the groups switched soups and spent another five days slurping away.
The researchers found that urine samples collected from the canned soup group spiked 1,221 percent over BPA levels over samples collected from the fresh soup group.
The study used Progresso brand canned soup, but the researchers told WebMD that "it's not about the brand of soup or canned soup, it is about the cans."
The researchers noted that the high levels of BPA might be transient and called for more research - but said that the time may have come to get BPA out of cans. As study author Karin Michels, associate professor in the school's department of epidemiology, put it in the statement, "It may be advisable for manufacturers to consider eliminating BPA from can linings."
A spokesman for General Mills, the company that makes Progresso soups, wasn't buying it.
"Scientific and governmental bodies worldwide have examined the science and concluded that the weight of evidence support the safety of BPA, including comprehensive risk assessments in Japan and in the European Union," Kirstie Foster, told Bloomberg Businessweek in an email.
A member of a conservative think tank in Washington, D.C. echoed those sentiments. Jeff Stier, a senior fellow at the National Center for Public Policy Research, told WebMD that the study "does nothing to substantiate claims that trace levels of BPA - even from daily canned soup consumption - have any effect on health."
The study was published online Nov. 21 in the Journal of the American Medical Association.