Consuming Canned Soup Linked to Greatly Elevated Levels of the Chemical BPA
BPA Found in Soup Can Lining, Associated with Adverse Health Effects in Humans
A new study from researchers at the Harvard School of Public Health (HSPH) has found that a group of volunteers who consumed a serving of canned soup each day for five days had a more than 1,000% increase in urinary bisphenol A (BPA) concentrations compared with when the same individuals consumed fresh soup daily for five days. The study is one of the first to quantify BPA levels in humans after ingestion of canned foods.
The findings were published online November 22, 2011, in the Journal of the American Medical Association (JAMA)and will appear in the November 23/30 print issue.
“Previous studies have linked elevated BPA levels with adverse health effects. The next step was to figure out how people are getting exposed to BPA. 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. This study suggests that canned foods may be an even greater concern, especially given their wide use,” said Jenny Carwile, a doctoral student in the Department of Epidemiology at HSPH and lead author of the study.
Exposure to the endocrine-disrupting chemical BPA, used in the lining of metal food and beverage cans, has been shown to interfere with reproductive development in animals and has been linked with cardiovascular disease, diabetes, and obesity in humans. In addition to the lining of food and beverage cans, BPA is also found in polycarbonate bottles (identified by the recycling number 7) and dentistry composites and sealants.
The researchers, led by Carwile and Karin Michels, associate professor in the Department of Epidemiology, set out to quantify whether canned-soup consumption would increase urinary BPA concentrations relative to eating fresh soup.
They recruited student and staff volunteers from HSPH. One group consumed a 12-ounce serving of vegetarian canned soup each day for five days; another group consumed 12 ounces of vegetarian fresh soup (prepared without canned ingredients) daily for five days. After a two-day “washout” period, the groups reversed their assignments.
Urine samples of the 75 volunteers taken during the testing showed that consumption of a serving of canned soup daily was associated with a 1,221% increase in BPA compared to levels in urine collected after consumption of fresh soup.
The researchers note that the elevation in urinary BPA concentrations may be temporary and that further research is needed to quantify its duration.
“The magnitude of the rise in urinary BPA we observed after just one serving of soup was unexpected and may be of concern among individuals who regularly consume foods from cans or drink several canned beverages daily. It may be advisable for manufacturers to consider eliminating BPA from can linings,” said Michels, senior author of the study.
Support for this study was provided by an Allen Foundation grant and a Training Grant in Environmental Epidemiology from the National Institute of Environmental Health Sciences.
“Canned Soup Consumption and Urinary Bishphenol A: A Randomized Crossover Trial,” Jenny L. Carwile, Xiaoyun Ye, Xiaoliu Zhou, Anotonia M. Calafat, Karin B. Michels, JAMA,online Nov. 22, 2011; in Nov. 23/30 print issue.
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Exposure to BPA, Chemical Used to Make Plastics, Before Birth Linked to Behavioral, Emotional Difficulties in Young Girls
Boston, MA – Exposure in the womb to bisphenol A (BPA) – a chemical used to make plastic containers and other consumer goods – is associated with behavior and emotional problems in young girls, according to a study led by researchers at Harvard School of Public Health (HSPH), Cincinnati Children’s Hospital and Medical Center, and Simon Fraser University in Vancouver, British Columbia.
BPA is found in many consumer products, including canned food linings, polycarbonate plastics, dental sealants, and some receipts made from thermal paper. Most people living in industrialized nations are exposed to BPA. BPA has been shown to interfere with normal development in animals and has been linked with cardiovascular disease and diabetes in people. In a 2009 study, HSPH researchers showed that drinking from polycarbonate bottles increased the level of urinary BPA.
In this study, published October 24, 2011, in an advance online edition of Pediatrics, lead author Joseph Braun, research fellow in environmental health at HSPH, and his colleagues found that gestational BPA exposure was associated with more behavioral problems at age 3, especially in girls.
The researchers collected data from 244 mothers and their 3-year-old children in the Health Outcomes and Measures of the Environment Study, conducted in the Cincinnati area. Mothers provided three urine samples during pregnancy and at birth that were tested for BPA; their children were tested each year from ages 1 to 3. When the children were 3 years old, the mothers completed surveys about their children's behavior. “None of the children had clinically abnormal behavior, but some children had more behavior problems than others. Thus, we examined the relationship between the mom's and children’s BPA concentrations and the different behaviors,” Braun said.
BPA was detected in over 85% of the urine samples from the mothers and over 96% of the children’s urine samples. The researchers found that maternal BPA concentrations were similar between the first sample and birth. The children’s BPA levels decreased from ages 1 to 3, but were higher and more variable than that of their mothers.
After adjusting for possible contributing factors, increasing gestational BPA concentrations were associated with more hyperactive, aggressive, anxious, and depressed behavior and poorer emotional control and inhibition in the girls. This relationship was not seen in the boys.
The study confirms two prior studies showing that exposure to BPA in the womb impacts child behavior, but is the first to show that in uteroexposures are more important than exposures during childhood, Braun said. “Gestational, but not childhood BPA exposures, may impact neurobehavioral function, and girls appear to be more sensitive to BPA than boys,” he said.
Although more research is needed to fully understand the health effects of BPA exposure, clinicians can advise those concerned to reduce their BPA exposure by avoiding canned and packaged foods, thermal paper sales receipts, and polycarbonate bottles with the number 7 recycling symbol, the authors wrote.
Bruce Lanphear of Simon Fraser University was senior author of the study.
The study was funded in part by the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency.
“Impact of Early Life Bisphenol A Exposure on Behavior and Executive Function in Children,” Joe M. Braun, Amy E. Kalkbrenner, Antonia M. Calafat, Kimberly Yolton, Xiaoyun Ye, Kim N. Dietrich, and Bruce P. Lanphear. Pediatrics:online October 24, 2011.
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