Why pregnant people shouldn’t eat fast food

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Pregnant people should avoid ultra-processed and fast food because of plastic contamination, a new study suggests.

If you’re pregnant, you may want to think twice before making a hamburger run or reaching for a prepackaged pastry. Oddly enough it’s not the food, but what touches the food before you eat it.

Research shows that phthalates, a class of chemicals associated with plastics, can shed from the wrapping, packaging, and even from plastic gloves worn by food handlers into food. Once consumed during pregnancy, the chemicals can get into the bloodstream, through the placenta, and then into the fetal bloodstream.

The chemical can cause oxidative stress and an inflammatory cascade within the fetus, researchers note. Previous literature has indicated that exposure to phthalates during pregnancy can increase the risk of low birth weight, preterm birth, and child mental health disorders such as autism and ADHD.

The new study is the first in pregnant women to show that diets higher in ultra-processed foods are linked to greater phthalate exposures, the authors write.

“When moms are exposed to this chemical, it can cross the placenta and go into fetal circulation,” says senior author Sheela Sathyanarayana, a pediatrician with University of Washington Medicine and a researcher at the Seattle Children’s Research Institute.

The analysis involved data in the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) research cohort, which comprised 1,031 pregnant individuals in Memphis, Tennessee, who were enrolled between 2006 and 2011. Phthalate levels were measured in urine samples collected from during the second trimester of pregnancy.

The researchers found that ultra-processed food composed 10% to 60% of participants’ diets, or 38.6%, on average. Each 10% higher dietary proportion of ultra-processed food was associated with 13% higher concentration of di(2-ethylhexyl) phthalate, one of the most common and harmful phthalates. The phthalate amounts were derived through urine samples taken from the women in the study.

Ultra-processed foods, according to the researchers, are made mostly from substances extracted from foods such as oils, sugar, and starch, but have been so changed from processing and the addition of chemicals and preservatives to enhance their appearance or shelf life that they are hard to recognize from their original form, 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 the employees and the storage, preparation, serving equipment, or tools may be the main sources of exposure. Both frozen and fresh ingredients would be subject to these sources, says lead author Brennan Baker, a postdoctoral researcher in Sathyanarayana’s lab.

This is the first study, the researchers say, to identify ultra-processed foods as a link between exposure to phthalates and the socioeconomics issues facing the mothers.

The mothers’ vulnerability might stem from experiencing financial hardships and from living in “food deserts” where healthier, fresh foods are harder to obtain and transportation to distant markets is unrealistic.

“We don’t blame the pregnant person here,” says Baker. “We need to call out manufacturers and legislators to offer replacements, and ones that may not be even more harmful.”

More legislation is needed, the authors say, to prevent phthalate contamination in foods by regulating the composition of food wrapping or even the gloves that food handlers may use.

What should pregnant women do now? Sathyanarayana says that pregnant women should try to avoid ultra-processed food as much as they can, and seek out fruits, vegetables, and lean meats. Reading labels can come into play here, she adds.

“Look for the lower number of ingredients and make sure you can understand the ingredients,” she says. This applies even to “healthy foods” such as breakfast bars. See if it’s sweetened with dates or has a litany of fats and sugars in it, she says.

The National Institutes of Health funded the work.

Source: University of Washington