People who reported eating fast food in the last 24 hours had elevated levels of some industrial chemicals in their bodies, according to a new analysis of data from federal nutrition surveys.
The study is the first broad look at how fast food may expose the public to certain chemicals, called phthalates, that are used to make plastics more flexible and durable. The chemicals, which don’t occur in nature, are common in cosmetics, soap, food packaging, flooring, window blinds, and other consumer products. The Centers for Disease Control says "phthalate exposure is widespread in the U.S. population."
Though the health consequences of encountering these substances aren’t fully known, scientists have increasingly focused on their effects on health and development, particularly for pregnant women and children. Research in rats has shown that they can disrupt the male reproductive system, and there’s evidence for similar effects in humans.
The latest research suggests that fast food is a significant source of the chemicals, which may leach into food from machinery used in processing or packaging, or from gloves worn by workers.
"Right now there are few choices for individuals who are interested in reducing their exposure, and there’s also not very much regulation” of phthalates, said Ami Zota, assistant professor of environmental and occupational health at the George Washington University Milken Institute School of Public Health. In the U.S., "research happens once they’ve been introduced in commerce, rather than before,” she said.
Zota and colleagues from GW analyzed data from almost 9,000 people who participated in federal nutrition surveys between 2003 and 2010. Participants answered detailed questions about what they ate in the last 24 hours and gave urine samples that were analyzed for byproducts that indicated the presence of three chemicals. The study was published in the journal Environmental Health Perspectives, which is supported by the National Institutes of Health.
For two of the three substances Zota examined—phthalates designated as DEHP and DiNP—there was a significant relationship between fast-food intake and exposure. People who ate more fast food had more evidence of phthalates in their urine. The third chemical they measured was Bisphenol A, or BPA, which is commonly used to line aluminum cans. That wasn't significantly correlated with fast-food intake.
It’s difficult to determine what the health risks of phthalates are. The American Chemistry Council says that they’ve been thoroughly studied and “phthalates used in commercial products do not pose a risk to human health at typical exposure levels.” The Environmental Protection Agency, in a 2012 Phthalates Action Plan, notes that it is "concerned about phthalates because of their toxicity and the evidence of pervasive human and environmental exposure to them."
Japan banned vinyl gloves in food preparation over concerns about DEHP, and the European Union has limited the use of the chemicals in food products and toys. Some phthalates, including DEHP, were restricted in children’s toys in the U.S. by a 2008 law.
The latest study is based on snapshot surveys, rather than following people over time. So it can’t establish that eating fast food caused people to have elevated levels of phthalates, but the association is strong. It also doesn’t tell us anything about the health effects of potential exposure to the chemicals from eating fast food.
The cost of endocrine-disrupting chemicals, a group that includes phthalates, in the EU is estimated to be €163 billion annually, or 1.28 percent of the EU’s gross domestic product, according to a recent paper by Leo Trasande, associate professor of pediatrics, environmental medicine, and population health at NYU School of Medicine. He said the study out today "adds further data to support the notion that people should avoid eating highly processed or highly packaged foods.” That doesn't mean just junk food, he notes. Canned vegetables or organic milk that’s been piped through plastic tubing could carry the same chemical risks. “It’s not fair to say, ‘Oh, these exposures only happen if you eat unhealthy foods.' "
Zota said that for people interested in reducing their exposure, “common-sense approaches will take you a long way. Eat organic when you can. If you can’t still, try to eat fresh vegetables,” she said. "Try to eat low on the food chain."