BPA Swimming in Your Soup

Study finds high levels of BPA in people who eat canned soup

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) It's an easy lunch or dinner. Just pry open a can of soup, heat it up, and eat. But next time, think twice: Your canned soup exposes you to a potentially harmful chemical called BPA.

Bisphenol-A, commonly called BPA, is a chemical compound used in the lining of canned foods. It's a controversial chemical because it's been associated with a variety of reproductive health problems. A new study found higher levels of BPA in people who eat canned soup than was previously suspected.

"Reduce your consumption of canned foods to lower exposure to BPA."

BPA is used in many consumer products. You may be familiar with BPA in plastic baby bottles and water bottles, like Nalgenes. Manufacturers have moved away from BPA in these plastics, and now market BPA-free products due to public health concerns.

However, BPA is still used in the epoxy resins of aluminum cans – that waxy lining inside your can of soup or green beans. It's there to prevent corrosion. But previous studies have shown that BPA leaches from those linings into food and drinks.

Scientists are concerned about BPA because its chemical structure mimics that of estrogen. Estrogen is the female sex hormone, and it's naturally found inside human bodies. But too much estrogen – or an unnatural amount of estrogen – is bad for you. Studies have associated BPA with reproductive health issues in both men and women. Exposure to BPA is linked to breast and prostate cancers in humans, and prenatal exposure has been shown to affect behavior in children.

A research team led by Dr. Karin Michels, an associate professor at the Harvard School of Public Health, compared exposure levels in people who ate canned soup every day for lunch compared to people who ate fresh soup.

The trial period was five days. After five straight days of soup, the researchers found that BPA levels in the canned soup group was 1,221 percent higher than the fresh soup group. Dr. Michels said the magnitude of the increase was a surprise. Previous studies had found less dramatic increases after people drank from bottles containing BPA.

The canned soup group had BPA levels of 20.8 micrograms per liter of urine, whereas the fresh soup group had levels of 1.1 micrograms per liter. In the general population, levels are 1 to 2 micrograms per liter.

But how much BPA is safe for human exposure is still under active debate. Some scientists say that the levels present in the average American are dangerous. The FDA has stated that it has “some concern” about the health effects of BPA.

Dr. Michels said that the study suggests higher levels of BPA in people who consume foods and beverages from cans that use the chemical. She added that food manufacturers might want to consider alternatives for BPA in their cans.

The study was published in November 2011 in the Journal of the American Medical Association.

Reviewed by: 
Review Date: 
November 23, 2011
Last Updated:
November 28, 2011