STANFORD, Calif., June 30 (UPI) -- Although BPA is no longer used in many plastics, including baby bottles and food containers, it is still used in many canned foods, leading to varying levels of exposure for people who eat those foods, depending on what foods they eat.
A large study of foods and tests of urine in people who consume them shows canned soups, pastas and vegetables have different levels of BPA, which poses a threat to health, according to researchers at Stanford University and Johns Hopkins University.
Previous studies have shown the potential for BPA to disrupt hormone function and the reproductive system, and have linked it to increased risk for health conditions such as diabetes and cardiovascular disease.
The concerns also extend to other chemicals used in food packaging such as the BPA alternative BPS, which was shown in a study earlier this year to speed up embryonic development and disrupt the reproductive system, similar to the effects of BPA.
The effects of BPA in canned products -- it is used to make resins that coat the insides of food cans and jar lids -- have been examined only in small studies, researchers say, making their study a significant insight into the risks of its continued use.
The new study, they say, also lends credence to concerns that children who eat school lunch are being exposed to varying and unknown levels of BPAs as school cafeterias have increased their use of canned vegetables and fruit to meet health guidelines for meals while not blowing their budgets.
For the study, published in the journal Environmental Research, researchers evaluated data on 7,669 people age 6 and older who participated in the National Health and Nutrition Examination Survey between 2003 and 2008.
Overall, 9 percent of participants consumed one canned food in the previous 24 hours and 2 percent had consumed two or more canned foods. For those who ate one canned food, BPA concentration in their urine was 24 percent higher, while those who'd eaten two or more had 54 percent higher levels.
These levels were different for people who consumed different foods, however, with 41 percent higher BPA present in urine for people who ate vegetables or fruit, 70 percent higher for those eating canned pasta and 229 percent higher for canned soups.
Beverages in cans, however, were not linked to concentrations of BPA in urine, the researchers report.
The difference between types of food, however, is concerning, the researchers say, because it appears to be somewhat unpredictable. They add that food companies should continue to follow the lead of container manufacturers in eliminating the chemical from use based on its proven threat to health.
"The FDA no longer allows BPA to be used in baby bottles, sippy cups and liquid infant formula canned linings, and many food and beverage companies are moving away from the use of BPA," Jennifer Hartle, a post-doctoral researcher at Stanford who led the study, said in a press release. "However, we do not know if synthetic BPA replacements are safe either."
Countering the potential risk of BPA and other products used in food packaging, the researchers suggest expansion of testing and regulation for other chemicals, none of which are monitored in national studies, they say.