If you’re pregnant, you might want to think twice before making a hamburger or reaching for prepackaged dough, according to research published last month in the journal Environmental International.
Surprisingly, it’s not the food that the report targets — not the fries, the burgers, or even the shakes and cakes — but what touches the food before you eat it.
Research shows that phthalates, a class of chemicals associated with plastics, can be leached from packaging, packaging and even the plastic gloves worn by food handlers on food. Once consumed during pregnancy, the chemicals can enter the bloodstream, through the placenta, and then into the fetus’s bloodstream.
The chemical can cause oxidative stress and an inflammatory cascade inside the fetus, the researchers noted. Previous literature has shown that exposure to phthalates during pregnancy can increase the risk of low birth weight, premature birth, and mental health disorders in children, such as autism and ADHD.
This is the first study in pregnant women to show that diets higher in ultra-processed foods are associated with greater exposure to phthalates, the authors wrote.
“When mothers are exposed to this chemical, it can cross the placenta and enter the fetal circulation,” said senior author Dr. Sheela Sathyanarayana, a UW Medicine pediatrician and researcher at the Seattle Children’s Research Institute.
This analysis included data in the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) research group, which included 1,031 pregnant women in Memphis, Tenn., who were enrolled between 2006 and 2011. Phthalate levels were measured in urine samples collected the second trimester of pregnancy.
The researchers found that highly processed foods made up 10% to 60% of the participants’ diets, or 38.6%, on average. Every 10% higher dietary proportion of highly processed foods was associated with a 13% higher concentration of di(2-ethylhexyl) phthalate, one of the most common and harmful phthalates. The amounts of phthalates were derived from urine samples taken from the women in the study.
Ultra-processed foods, according to the researchers, are mostly made from substances extracted from foods such as oils, sugar and starch, but have been so altered by processing and the addition of chemicals and preservatives to improve appearance or shelf life those that are difficult to recognize from their original form, the researchers noted. These include packaged cake mixes, for example, or packaged French fries, hamburger buns and soft drinks.
When it comes to fast food, gloves worn by workers and storage, preparation, equipment or serving utensils can be the main sources of exposure. Both frozen and fresh ingredients would be subject to these sources, said lead author Brennan Baker, a postdoctoral researcher in Sathyanarayana’s lab.
This is the first study, the researchers say, to identify highly processed foods as a link between phthalate exposure and socioeconomic problems faced by mothers. Mothers’ vulnerability may be due to economic hardship and living in “food deserts,” where the healthiest, freshest foods are harder to come by and transportation to distant markets is unrealistic.
“We’re not blaming the pregnant woman here,” Baker said. “We need to call on manufacturers and lawmakers to offer replacements, and ones that may not be even more harmful.”
More legislation is needed, the authors said, to prevent phthalate contamination of food by regulating the composition of food packaging or even the gloves that food handlers may use.
What should pregnant women do now? Sathyanarayana said pregnant women should try to avoid highly processed foods as much as possible and look for fruits, vegetables and lean meat. Reading tags can play a role here, he added.
“Look for the smallest number of ingredients and make sure you can understand the ingredients,” he said. This even applies to “healthy foods” like breakfast bars. See if it’s sweetened with dates or high in fat and sugar, he said.
This study was funded in part by the National Institutes of Health (UG3UH3OD023271).