Teenagers who eat too much fast-food may be exposed to potentially harmful chemicals that disrupt hormone balance, a study warns.
Phthalates, a group of chemicals used in food packaging and processing materials, are known to disrupt hormones in humans and are linked to a long list of health problems.
The study, published in the journal Environment International, is the first to compare phthalate exposures in people who reported dining out to those more likely to enjoy home-cooked meals.
"Pregnant women, children and teens are more vulnerable to the toxic effects of hormone-disrupting chemicals, so it's important to find ways to limit their exposures," said Julia Varshavsky from the George Washington University in the US.
People who reported consuming more restaurant, fast food and cafeteria meals had phthalate levels that were nearly 35 per cent higher than people who reported eating food mostly purchased at the grocery store, according to the research.
"This study suggests food prepared at home is less likely to contain high levels of phthalates, chemicals linked to fertility problems, pregnancy complications and other health issues," said Ami Zota from the George Washington University.
About 10,253 people were asked to recall what they ate and where their food came from in the previous 24 hours.
The researchers then analysed the links between what people ate and the levels of phthalate break-down products found in each participant's urine sample.
They found that 61 per cent of the participants reported dining out the previous day.
According to the study, the association between phthalate exposure and dining out was significant for all age groups but the magnitude of association was highest for teenagers.
Adolescents who were high consumers of fast food and other food purchased outside the home had 55 per cent higher levels of phthalates compared to those who only consumed food at home.
Certain foods, and especially cheeseburgers and other sandwiches, were associated with increased levels of phthalates - but only if they were purchased at a fast-food outlet, restaurant or cafeteria.
The study found that sandwiches consumed at fast food outlets, restaurants or cafeterias were associated with 30 per cent higher phthalate levels in all age groups.