If the high fat, calorie, sugar, and sodium content of fast food weren’t enough to deter you, new research offers another reason to change your eating habits. People who had eaten fast food in the previous 24 hours showed significantly higher levels of phthalates—a family of industrial chemicals used to make plastics more flexible—than people who had skipped the drive-through. And the more they ate, the worse it got.
Among the nearly 9,000 participants in a study from George Washington University published in the journal Environmental Health Perspectives, the "high consumers"—ones who had eaten the most fast food (35% of their caloric intake or more)—had anywhere from 20% to 40% higher levels of two specific phthalates than people who hadn’t eaten fast food.
What that means for human health isn’t entirely clear. Phthalates, which are used in everything from raincoats to vinyl flooring to food and beverage containers, are so pervasive that nearly all Americans have some of the chemicals’ breakdown products in their bodies already. While the American Chemical Council recently issued a statement that the phthalates currently used "do not pose a risk to human health at real-life exposure levels," the Centers for Disease Control and Prevention have stated that the health effects are "unknown" and that "more research is needed." Previous studies on animals have linked phthalates to a wide range of issues, including hormone disruptions, demasculinization (problems with male sexual organ development), cardiovascular problems, and cancer while phthalate studies involving humans have linked the chemicals to attention deficit hyperactive disorder (ADHD) and asthma in children. DEHP and DiNP—the two phthalates examined in the George Washington University research—are already banned from being used in manufacturing children’s toys and child-care products.
"We know from a wealth of emerging evidence from both human studies as well as animal studies that we do see adverse health effects even at low levels in the range of what we’re finding in this study," says Ami R. Zota, an assistant professor at GW’s Milken Institute School of Public Health and the study’s lead author. "It would be very difficult to eliminate everyone’s exposures to phthalates."
Because phthalates are everywhere, nailing down where exactly our bodies are picking up these chemicals is a major problem, one that Zota is quick to point out that her study doesn’t definitively solve. The George Washington University research only concludes that fast food, defined here as any food available as a carry-out/delivery item or available at a restaurant without a waitstaff, "may be a source of exposure" to phthalates. Zota says that a longitudinal study would be required to confirm these findings.
To determine the specific impact of phthalates, "we need more information," says Linda S. Birnbaum, director of the National Institute of Environmental Health Sciences. We also need to broaden the ways in which these chemicals are studied.
"No one’s exposed to one phthalate at a time, and there’s some data that suggests that at least the demasculization effects act in an additive fashion," Birnbaum says. "Looking at [phthalates] one at a time may not actually predict what the risks might be."
Zota says that the drastic difference between phthalate levels in people who ate lots of fast food versus those who didn’t is enough to push her to continue studying whether phthalates could be sneaking into our bodies through the food we eat.
"You don’t find such solid results in this type of research everyday," she says. "I think it does reflect something real going on."