Pregnant women should avoid fast food, mostly for its packaging

Science and Health

Everyone should avoid eating a lot of ultra-processed foods, as medical studies studies have shown that a diet based on such products is linked to a greater risk of cardiovascular disease including heart attacks and strokes, obesity, hypertension, breast and colorectal cancer, and premature death.

But if you’re pregnant, the danger is even greater, and you should think twice before ordering a hamburger or reaching for a prepackaged pastry, according to research just published in the journal Environmental International under the title “Ultra-processed and fast-food consumption, exposure to phthalates during pregnancy, and socioeconomic disparities in phthalate exposures.”

It’s not the actual food that poses a significantly higher risk to pregnant women but the packaging that touches the food before they eat it. Recent increases in global intake of highly processed foods have coincided with an increase in chronic diseases like metabolic syndrome and inflammatory bowel disease, prompting scientists to explore potential connections between levels of food processing and the risk of chronic illnesses. Processed diets may also impact health through mechanisms other than nutritional quality, and the mechanisms underlying those impacts can vary greatly across processed foods. 

Growing evidence suggests that chemicals deliberately added to processed foods to extend shelf life or to impart certain properties including color and texture, or which inadvertently contaminate food through contact during processing and packaging, including phthalates may contribute to human disease.

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 noted. 

Pregnant woman (illustrative) (credit: INGIMAGE)

Known link between phthalates exposure and child mental disorders

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.

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


“When moms are exposed to this chemical, it can cross the placenta and go into fetal circulation,” said senior author and pediatrician Dr. Sheela Sathyanarayana of the University of Washington in Seattle. 

This analysis involved data in the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) research cohort that comprised 1,031 pregnant women 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.

Such junk foods 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, 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 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, said lead author Brennan Baker, a postdoctoral researcher in Sathyanarayana’s lab.

They said theirs is the first study to identify ultra-processed foods as a link between exposure to phthalates and the socio-economics 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 woman here,” said 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 said, to prevent phthalate contamination in foods by regulating the composition of food wrapping or even the gloves that food handlers use. 

Sathyanarayana said that pregnant women should try to avoid ultra-processed food as much as they can and instead consume fruits, vegetables and lean meats.  Reading labels can come into play here, she added. 

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