Danger from Phthalates: Pregnant Women Should Avoid Heavily Processed Foods

Research shows that phthalates, a class of chemicals associated with plastics, can migrate into these products from the packaging, wrapping and even plastic gloves worn by people handling food. Once consumed during pregnancy, the chemicals can pass through the placenta into the bloodstream and then into the fetus’s bloodstream. The chemical can cause oxidative stress and an inflammatory cascade in the fetus, the researchers found. Previous literature has suggested that exposure to phthalates during pregnancy can increase the risk of low birth weight, premature birth, and childhood mental illnesses such as autism and ADHD.

Ultra-Processed Foods and Phthalates

This is the first study of pregnant women to show that a diet higher in ultra-processed foods is associated with higher levels of phthalates, the authors write. “When mothers are exposed to this chemical, it can cross the placenta and enter the fetal circulation,” said lead author Dr. Sheela Sathyanarayana, a pediatrician and researcher at the Seattle Children’s Research Institute.

This analysis included data from the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) research cohort, which included 1,031 pregnant individuals in Memphis, Tennessee, enrolled between 2006 and 2011. Phthalate levels were measured in urine samples collected in the second trimester of pregnancy. The researchers found that ultra-processed foods made up 10 to 60% of the participants’ diets, with an average of 38.6%. Each 10% increase in the proportion of ultra-processed foods in the diet was associated with a 13% increase in the concentration of di(2-ethylhexyl) phthalate, one of the most common and harmful phthalates. The levels of phthalates were determined by analyzing urine samples from the women in the study.

Ultra-processed foods are made primarily from substances derived from foods such as oils, sugars and starches, according to the researchers. However, they have been so altered as to be barely recognizable from their original forms that they have been processed and have had chemicals and preservatives added to improve their appearance or shelf life, the researchers said. These include, for example, packaged cake mixes or packaged chips, hamburger buns and soft drinks.

Improving Laws

When it comes to fast food, the main sources of exposure may be the gloves worn by employees and the storage, preparation and serving equipment or tools. Both frozen and fresh ingredients would be exposed to these sources, said lead author Brennan Baker, a postdoc in Sathyanarayana’s lab. This is the first study, researchers say, that identifies ultra-processed foods as the link between phthalate exposure and maternal socioeconomic challenges. The vulnerability of the mothers could be due to financial difficulties that prevent them from easily obtaining healthier, fresh foods.

The authors believe that more legislation is needed to prevent phthalate contamination in food, by regulating the composition of food packaging or even the gloves that food handlers are allowed to use, and that pregnant women should try to avoid ultra-processed foods as much as possible, instead opting for fruit, vegetables and lean meat. Reading labels can play a role here. “Look for fewer ingredients and make sure you can understand the ingredients. This applies even to ‘healthy foods’ like breakfast bars. See if they are sweetened with dates or contain a variety of fats and sugars ,” Sathyanarayana said.

Phthalates Can Disrupt a Hormone Needed for a Healthy Pregnancy

Other research has shown that exposure to phthalates, which are found in all kinds of everyday products, can disrupt a hormone that is needed for a healthy pregnancy. The study examined the effects of phthalates, which are added to plastics to increase flexibility, on placental corticotropin-releasing hormone (pCRH), which is produced by the placenta and increases during pregnancy. The hormone plays an important role in promoting the onset of labor, but when levels are high or rise rapidly earlier in pregnancy, it can lead to preterm birth and fetal growth problems, as well as high blood pressure, diabetes and postpartum depression.

Researchers analyzed data from 1,018 low-risk pregnant women carrying a single fetus at two time points, mid- and late-pregnancy. They found that the presence of various phthalates was associated with higher levels of the pCRH hormone in mid-pregnancy but lower levels of pCRH later in pregnancy. These levels were strongest in women who developed pregnancy complications such as gestational diabetes and high blood pressure, suggesting that women who develop complications may be especially vulnerable to this hormonal disruption.

This is one of the first and largest studies to date examining how these chemicals and the association with pCRH disrupt the functioning of the endocrine system, which is particularly sensitive during pregnancy. “The association between phthalates and pCRH in women with pregnancy complications became stronger as pregnancy progressed. We know very little about how women with pregnancy complications are affected by environmental exposures. This study sets the stage for future research in this area,” said Emily S. Barrett, associate professor at Rutgers School of Public Health and a member of the Environmental and Occupational Health Sciences Institute. Produced by the placenta, pCRH is structurally identical to corticotropin-releasing hormone (CRH), which is produced by the brain in response to stress. While this study did not find that women who experienced childhood trauma were more susceptible to the hormone-disrupting effects of phthalates, previous research found that pCRH levels were higher in women who had experienced childhood trauma, suggesting that traumatic events may affect pregnancy decades later.