SAN FRANCISCO - A peer-reviewed study published today in Environmental Health Perspectives suggests that food packaging is a substantial source of exposure to the endocrine-disrupting chemical bisphenol A (BPA), which laboratory studies have linked to breast cancer, infertility, early puberty, and other serious health problems. In this unprecedented human study, scientists at the Breast Cancer Fund and Silent Spring Institute discovered an average drop of 60 percent in BPA levels when study participants ate a diet that avoided contact with BPA-containing food packaging, such as canned food and polycarbonate plastic.

“This study suggests that removing BPA from food packaging will remove the number one source of BPA exposure,” said Janet Gray, Ph.D., Science Advisor to the Breast Cancer Fund and professor at Vassar College. “The study should serve as a call to action for industry and government to get BPA out of food packaging and to fix the broken chemical management system that allows it to be there in the first place.”

The study, “Food Packaging and Bisphenol A and Bis(2-Ethyhexyl) Phthalate Exposure: Findings from a Dietary Intervention,” tested the levels of BPA in the urine of five San Francisco Bay Area families who had a high likelihood of regular exposure to food packaging containing BPA (they consumed canned foods and beverages, ate meals outside of the home, used polycarbonate water bottles, and/or microwaved in plastic). The families were provided with three days’ worth of freshly prepared organic meals with no canned food, and using only glass storage containers. The families’ urine was evaluated while they ate their typical diets, again during the period when they were provided with freshly-prepared meals, and then again after returning to their normal eating habits. While the families were eating the fresh-food diet, their BPA levels dropped on average by 60 percent. Reductions were even more pronounced—75 percent—for those with the highest exposures. When families returned to their regular diets, their BPA levels increased back to pre-intervention levels.

In addition to BPA, participants were tested for phthalates, plastic-softening chemicals that can interfere with reproductive development. Levels of DEHP (a phthalate used in food packaging) dropped by an average of 50 percent during the intervention; and the highest exposures dropped by over 90 percent.

"Our study provides clear and compelling evidence that food packaging is the major source of exposure to BPA and DEHP,” said Ruthann Rudel, lead author of the study and Director of Research at Silent Spring Institute. “The study shows that a fresh-food diet reduces levels of these chemicals in children and adults by half, after just three days."

BPA and the phthalate DEHP are both used widely in food packaging. BPA is used to make polycarbonate plastics and is used in the lining of food cans, and DEHP is an additive used in some food containers and plastic wraps to increase flexibility. BPA and phthalates are both known as endocrine-disrupting chemicals because of their effects on hormone systems. BPA has been shown to mimic the hormone estrogen, and exposure has been associated with effects on the developing brain, reproductive system, and mammary and prostate glands in laboratory studies. Phthalates have been demonstrated to interfere with androgen signaling and male reproductive development in laboratory and human studies.

“The findings of this food packaging study suggest that if the food and food-storage industries reformulated packaging to remove BPA and phthalates, or if there were a federal ban of these chemicals in food packaging, a large portion of the population would experience a rapid reduction in the levels of these chemicals in their bodies,” said Dr. Gray. “Industry and government need to ensure the safety of any substitute chemicals before they are put into use.”

Suggestions from the Breast Cancer Fund and Silent Spring Institute for reducing exposure to BPA and DEHP include cooking at home with fresh foods and making some changes in the kitchen, such as avoiding canned foods, choosing glass and stainless steel food and beverage containers, and not microwaving in plastic. After aggregating the results of tests of 300 canned food products, the Breast Cancer Fund found that BPA especially leaches into canned foods that are acidic, salty or fatty, such as coconut milk, soup, meals (e.g., ravioli in sauce) and vegetables. For additional tips or to download a shopper’s guide, visit www.breastcancerfund.org.