By Amy Norton
THURSDAY, March 29, 2018 (HealthDay News) -- People who like to dine out may unwittingly order a side of potentially harmful chemicals, new research suggests.
The study, involving more than 10,000 Americans, found that those who'd dined out the day before generally had higher urine levels of chemicals called phthalates, versus people who'd had all their meals at home.
The findings suggest that old-fashioned home-cooked meals could be one way for people to reduce their intake of phthalates -- which have been linked to certain health risks.
Phthalates are added to plastics to make them more flexible and difficult to break. Lab studies have shown the chemicals to be "endocrine disruptors" -- which means they can interfere with how hormones work in the body.
In humans, studies have found correlations between phthalate exposure and reproductive issues -- including preterm birth and fertility problems, said lead researcher Ami Zota. She is an assistant professor of environmental and occupational health at George Washington University, in Washington, D.C
Several phthalates have been banned from children's toys and certain child-care products, such as teething rings, according to the U.S. Consumer Product Safety Commission.
However, phthalates remain in a huge range of products, from electrical cables and medical supplies to detergents and cosmetics.
For most people, diet is the primary route of exposure, said Zota.
That's because phthalates can get into food during processing, or possibly during transportation, through packaging or even via the gloves used for food handling, Zota explained.
So it's not surprising, she said, that people who eat out can be exposed to more phthalates. In fact, her team found in an earlier study that fast-food fans generally had higher phthalate levels than people who rarely ate those foods.
The new study, published online March 28 in the journal Environment International, suggests fast food is not the only culprit.
On average, the study found, people who'd dined out -- at any type of restaurant or cafeteria -- had a phthalate intake that was 35 percent higher than people who'd eaten only home-prepared meals.
When the researchers looked at particular types of food, they found that hamburgers and other meat sandwiches stood out: People who'd eaten those sandwiches the day before tended to have higher phthalate levels -- but only if they'd gotten them from a restaurant or cafeteria.
The evidence was weaker when it came to fries and pizza.
According to Zota, that is in line with research suggesting that animal proteins might be a stronger "vehicle" for phthalates. It's not clear why, but the fat content might be a factor, she said.
Sarah Evans is an instructor in environmental medicine and public health at Mount Sinai's Icahn School of Medicine, in New York City.
Eating more home-cooked meals could help limit phthalate exposure, Evans said -- but people need to be mindful of the foods they choose.
That's because phthalates can lurk in the processed, packaged foods sold at grocery stores, too.
"The best way to reduce exposure is to eat whole, fresh foods at home as often as possible," said Evans, who was not involved in the study. "Phthalates have been shown to accumulate in high-fat foods, so limiting consumption of those items may be effective at reducing exposure."
Zota called that a "win-win" scenario. Diets rich in whole foods are also more nutritious, and lower in sugar and salt, she pointed out.
Evans also suggested using glass or stainless steel containers for food preparation and storage, and avoiding microwaving plastic -- since heat may cause phthalates to "seep out."
However, there is only so much consumers can do to avoid phthalates, both Evans and Zota noted.
"Increased oversight and regulation of food packaging and the food manufacturing process is necessary to protect the population from the harmful effects of phthalate exposure," Evans said.