well.blogs.nytimes.com - August 29th, 2012
A new study by Harvard researchers may provide another reason to skip the canned pumpkin and cranberry sauce this Thanksgiving. People who ate one serving of canned food daily over the course of five days, the study found, had significantly elevated levels — more than a tenfold increase — of bisphenol-A, or BPA, a substance that lines most food and drink cans.
Most of the research on BPA, a so-called endocrine disruptor that can mimic the body’s hormones, has focused on its use in plastic bottles. It has been linked in some studies to a higher risk of cancer, heart disease, diabetes and obesity, and health officials in the United States have come under increasing pressure to regulate it. Some researchers, though, counter that its reputation as a health threat to people is exaggerated.
The new study, which was published Tuesday in The Journal of the American Medical Association, is the first to measure the amounts that are ingested when people eat food that comes directly out of a can, in this case soup. The spike in BPA levels that the researchers recorded is one of the highest seen in any study.
“We cannot say from our research what the consequences are,” said Karin Michels, an associate professor of epidemiology at Harvard Medical School and an author of the study. “But the very high levels that we found are very surprising. We would have never expected a thousand-percent increase in their levels of BPA.”
As part of the study, Dr. Michels and her colleagues recruited a group of 75 staff members and students at the Harvard School of Public Health, split them into two groups, and then followed them for two weeks. During the first week, one group ate a 12-ounce serving of vegetarian soup from a common brand of canned soup every day for five days; the other group, meanwhile, ate 12 ounces of vegetarian soup made from fresh ingredients each day. Then, after a two-day soup-free “wash out” period, the groups switched roles and were followed for five more days. At the end of each five-day period, the subjects provided urine samples.