Eating canned soup may increase consumers’ levels of a chemical linked to obesity and cancer, according to a study published last week by scientists at the Harvard School of Public Health in the Journal of the American Medical Association.
Prior research has linked the substance, bisphenol A (BPA), to weight problems, neurobehavioral deficits in children, and increased risk of breast and prostate cancer.
Results of the HSPH study showed that volunteers who consumed a 12-ounce portion of vegetarian canned soup daily for five days experienced over a thousand percent increase in urinary BPA concentration compared to volunteers who ate fresh vegetarian soup.
Jenny L. Carwile—a doctoral student in epidemiology at HSPH and lead author of the study—said she was not expecting such drastic results.
“The increase in BPA was surprising because we gave the candidates just one 12-ounce serving of soup per day,” Carwile said.
Carwile previously conducted a study on consumption of liquids from polycarbonate water bottles which found that water bottle use caused a 66 percent increase in BPA.
“The results from the tests on the polycarbonate water bottles showed a much more modest association to BPA,” she said. “I was expecting something more on par with that.”
Consumer Reports magazine established a connection between canned food and BPA in a study published in 2009, and Carwile and her colleagues, led by senior author and Harvard professor Karin Michels, sought to build upon that link in this most recent study.
“We extended the study [in Consumer Reports] to look at the association between consumption of canned foods and the BPA levels in the people themselves,” she said.
Though her study focused exclusively on canned soup because of the utility of its preparation, Carwile emphasized that it is not only soups that can increase BPA levels.
“This is not about the brand of canned soup,” she said. “It’s not even about canned soup. It’s about canned foods.”
Carwile said that she believes similar results would have been found had the subjects eaten other canned foods.
According to Harvard University Dining Services spokesperson Crista Martin, Harvard College dining halls do not serve canned soup.