• Posted February 12, 2024

Fast Food Wrappings May Pass on Toxic Chemicals to Pregnant Women

Think twice if you're pregnant and craving a packaged pastry or a take-out burger and shake.

That indulgence can do more than cause unwanted weight gain. A new study shows that phthalates, chemicals associated with plastics, can shed from packaging and even from plastic gloves worn by food handlers. 

If consumed during pregnancy, those chemicals can harm the fetus, researchers warn.

"When moms are exposed to this chemical, it can cross the placenta and go into fetal circulation," said senior study author Dr. Sheela Sathyanarayana, a pediatrician at UW Medicine and researcher at the Seattle Children's Research Institute.

She and her colleagues noted that phthalates can cause inflammation and oxidative stress in the fetus. (Oxidative stress is a harmful chemical imbalance in the body.) Earlier research has linked exposure to phthalates during pregnancy to a higher risk of pre-term birth, low birth weight and disorders in childhood such as autism and ADHD. 

The new study -- published recently in the journal Environment International -- examined data from 1,031 pregnant women who enrolled in a separate study of mental development and learning between 2006 and 2011. Phthalate levels were measured during participants' second trimester.

On average, ultra-processed food made up 39% of participants' diets. Each 10% increase in proportion of ultra-processed food was associated with a 13% higher level of di(2-ethylhexyl) phthalate, one of the most common and harmful of these chemicals. 

Researchers noted that ultra-processed foods are made largely from substances extracted from foods such as oils, sugar and starch. 

Food companies add chemicals and preservatives to extend their shelf life or make them more appealing, and some are hard to recognize from their original form. Researchers cited packaged cake mixes, french fries, hamburger buns and soft drinks as examples.

When it comes to fast food, though, gloves worn by workers and tools used in preparation, storage and serving may be the main sources of exposure, the study found. 

Lead study author Brennan Baker, a postdoctoral researcher in Sathyanarayana's lab, said both frozen and fresh ingredients are subject to these sources.

"We don't blame the pregnant person here," Baker said in a university news release. "We need to call out manufacturers and legislators to offer replacements, and ones that may not be even more harmful."

Researchers said this is the first study to show a link between ultra-processed foods, phthalate exposure and economic issues. Mothers' risk might owe to financial hardships and living in areas with limited access to healthy, fresh food is limited, they said.

They called for officials to regulate composition of food wrapping and gloves that food handlers may use. 

In the meantime, Sathyanarayana urged pregnant women to avoid ultra-processed food and seek out fruits, veggies and lean meats instead. Read labels carefully, she advised.

"Look for the lower number of ingredients and make sure you can understand the ingredients," she said, adding that this applies even to "healthy foods" such as breakfast bars.

More information

The Center for Research on Ingredient Safety at the University of Michigan has more about food wrap safety.

SOURCE: University of Washington School of Medicine, news release, Feb. 7, 2024