Federal standards for school meals are meant to keep kids healthy but with an emphasis solely on nutrition, schools may be missing something equally important: exposure to toxic chemicals.

A new study suggests school meals may contain unsafe levels of bisphenol A (BPA), a chemical often found in canned goods and plastic packaging that can disrupt human hormones and has been linked to health effects ranging from cancer to reproductive issues.

“I was shocked to see that virtually everything in school meals came from a can or plastic packaging.”

“During school site visits, I was shocked to see that virtually everything in school meals came from a can or plastic packaging,” says Jennifer Hartle, a postdoctoral researcher at the Stanford Prevention Research Center. “Meat came frozen, pre-packaged, pre-cooked, and pre-seasoned. Salads were pre-cut and pre-bagged. Corn, peaches, and green beans came in cans. The only items not packaged in plastic were oranges, apples, and bananas.”

The uptick in plastic packaging is a result of schools’ efforts to streamline food preparation and meet federal nutrition standards while keeping costs low, researchers say.

lunch tray

The main pathway for BPA exposure is through consumption of food and drinks that have contacted the chemical. Children, whose organ systems are still developing, are especially susceptible to hormone disruption from BPA. “Sometimes only small changes in hormone activity during development can cause permanently adverse effects,” the authors write in the study that is published in  the Journal of Exposure Science and Environmental Epidemiology.

Researchers track BPA intake in terms of micrograms per kilogram of body weight per day. In lab experiments, rodents experience toxicity at 2 micrograms per kilogram of body weight per day. But humans may metabolize BPA differently, Hartle says. Safe levels for BPA exposure should be in line with these low-dose toxicity findings to protect vulnerable populations like children.

To determine how much BPA students are ingesting, researchers interviewed school food service personnel, visited school kitchens and cafeterias in the San Francisco Bay Area, and analyzed studies on BPA food concentration values.

Low-income kids at high risk

Unsurprisingly, they found that BPA exposure varies, depending on what students eat.

Elementary school students consuming pizza and milk with sides of fresh fruits and vegetables would take in minimal levels of BPA. But a student consuming pizza and milk with canned fruits and vegetables could take in anywhere from minimal levels to 1.19 micrograms of BPA per kilogram of body weight per day. While most students would not consume the maximum amount, those who do would take in more than half of the dose shown to be toxic in animal studies in just one meal.

“With endocrine-disrupting chemicals particularly, there is so much uncertainty,” says Robert Lawrence, a medical doctor, one of the study’s authors, and director of the Johns Hopkins Center for a Livable Future. “We can’t tie a specific dose to a specific response like we can with lead. But we know BPA is impacting human health. Animal models are showing there can be a whole range of health effects. This research shows we should take a precautionary approach.”

Low-income children are particularly at risk of BPA exposure because they are more likely to eat federally funded meals instead of bringing lunch from home. Increasingly, students are eating not only lunch but also breakfast and sometimes dinner at school, exposing students to potentially dangerous levels of BPA.

“Even a dose of one extra microgram per day could be a big deal,” Hartle says. “If this is an avoidable exposure, do we need to risk it? If we can easily cut it out, why wouldn’t we?”

In 1988, the US Environmental Protection Agency defined safe BPA consumption levels as 50 micrograms or less per kilogram of body weight per day. Since then, hundreds of scientific papers have found detrimental biological effects of BPA at levels lower than the EPA standard. Recognizing the new scientific literature on BPA, the European Food Safety Authority recently updated its standards for safe BPA intake to 4 micrograms per kilogram of body weight per day – 46 micrograms less than the EPA standard.

The United States should consider following Europe’s lead by reducing its definition of safe BPA consumption levels, Hartle says. Another step would be for governing agencies to invest in more low-dose toxicity testing to provide more certainty around BPA’s toxicity at low levels.

Schools can protect children by limiting sources of BPA contamination. However, researchers caution that food containers labeled “BPA-free” are not necessarily a safe alternative because the chemicals used to replace BPA could be just as toxic. Parents should talk to principals and school administrators about getting more fresh fruits and vegetables into cafeterias, Hartle says. Feeding children more fresh food in packed lunches and at home is also an important step in limiting exposure.

“The bottom line is more fresh fruits and vegetables. There is a movement for more fresh veggies to be included in school meals, and I think this paper supports that.”


This text is published here under a Creative Commons License.
Author: Paige Miller-Stanford University
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