Over the years, an increasing number of published studies have warned the public about the potential health risks of being exposed to phthalates. But what exactly are they?

Phthalates are a group of chemicals used to soften plastics, making them more flexible and harder to break. People are exposed to them in varying degrees in the form of household cleaners, make-up, adhesives, plastics, fragrances, detergents, vinyl flooring and other everyday objects.

After the Centers for Disease Control and Prevention (CDC) expressed concern over their potential health risks, the class of chemicals was included by politicians Barbara Boxer and Henry Waxman in their Consumer Product Safety bill. After being passed in 2008, the use of some phthalates in certain products was banned. One study published in 2016 revealed how fast food consumers were exposed to higher levels of phthalates compared to people who rarely ate them.

The same group of researchers explored the link further, broadening the scope to dining out rather than exclusively looking at fast food consumption. They publishing their findings in the journal Environment International on Wednesday.

The new study analyzed data on 10,253 participants collected by the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2014. Participants were asked to recall what they ate and where their food came from in the previous 24 hours. Researchers also used measured levels of phthalate break-down products found in each participant's urine sample.

According to the results, 61 percent of the participants had reported dining out the previous day. Levels of phthalates in their bodies were observed as being 35 percent higher than those who chose to eat at home.

"Our findings suggest that dining out may be an important and previously under-recognized source of exposure to phthalates for the U.S. population," explains Dr. Ami Zota, senior author and assistant professor of environmental and occupational health at George Washington University. Food that was prepared at home is "less likely to contain high levels of phthalates, chemicals linked to fertility problems, pregnancy complications and other health issues," she added.

Food items such as burgers and sandwiches were linked to higher phthalate levels but only if they were purchased at a fast-food outlet, restaurant or cafe. It has been suggested that the phthalates used in packaging, gloves, take-out boxes and processing materials can contaminate the food they carry. 

While research is still on-going to determine the exact impact of phthalates on our health, many studies and cases have linked them to pregnancy complications, hormonal imbalances, childhood obesity, diabetes, fertility problems, and the increased risk of breast cancer and endometriosis. The study noted that pregnant women and adolescents were most vulnerable to the toxic effects of the chemicals.

Researchers advise eating in as often as possible to reduce these risks. 

"Preparing food at home may represent a win-win for consumers. Home cooked meals can be a good way to reduce sugar, unhealthy fats and salt. And this study suggests it may not have as many harmful phthalates as a restaurant meal," Dr. Zota said.