Recent research examined levels of endocrine disruptors called phthalates in people eating fast food. Researchers found evidence of a dose–response relationship between fast food intake and exposure to phthalates - the more one eats fast food, the more phthalates (actually metabolites of the phthalates) can be measured in the person's urine. Fast food consumers had higher urinary levels of the phthalates DEHP, DiNP, and BPA than those not consuming fast food (even though the differences in levels of BPA among groups were "non-significant"). This is of concern because these endocrine disruptors are linked to a number of health problems. (Earlier discussion of this research.)
DEHP, DiNP, and BPA are detected in over 90% of the population in the US, but since there are many health concerns - it is better to have lower levels than higher levels. (Zero levels would be best). Note that phthalates and BPA are quickly metabolized and excreted in urine, with elimination half-lives of less than 24 hr - which is why the study looked at what had been eaten in the last 24 hours. But this also shows that one can quickly reduce their levels in the body.
Some possible sources of phthalate contamination in fast food are: PVC tubing, vinyl gloves used for food handling, and food packaging, including beverage cans - the chemicals leach or migrate out into the food and then are ingested. (More on chemicals migrating from containers to food), Fast food was defined as food obtained from restaurants without waiter service and from pizza restaurants, as well as all carry-out and delivery food. Another excellent reason to cut back on fast food (like we don't have enough reasons already!). The following news report discusses the research. From Environmental Health Perspectives:
Phthalates in Fast Food: A Potential Dietary Source of Exposure
Many research studies have surveyed nutritional habits, but fewer have studied how food processing and packaging might introduce unwanted chemicals into foods. In this issue of EHP, researchers report that fast food consumption appears to be one source of exposure to the chemicals di(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DiNP).1
The authors used data from the National Health and Nutrition Examination Survey (NHANES) to estimate the percentage of individuals’ calories that came from fast food, fat intake attributable to fast food consumption, and fast food intake by food group. During NHANES interviews, respondents had reported their diet from the preceding 24 hours. Fast food was defined as food obtained from restaurants without waiter service and from pizza restaurants, as well as all carryout and delivery food.2 ....The final study population included nearly 9,000 people aged 6 years or older. Approximately one-third of people surveyed had eaten fast food in the preceding 24 hours. Study participants who ate fast food were more likely to be male, under age 40, and non-Hispanic black, and to have higher total calorie and total fat intake from fast food, compared with the general population.1
Fast food consumers had higher urinary levels of DEHP, DiNP, and BPA than non-consumers, although the differences in average urinary levels were small and for BPA were non-significant. When fast food intake was categorized by food group, DEHP metabolites were associated with intake of grains and “other” (a category that included vegetables, condiments, potato items, beverages, and more). DiNP metabolites were associated with intake of meat and grains.1
The authors also found that the associations between phthalates and fast food were not uniform across the population.1They speculate that the pronounced association they saw between fast food consumption and DEHP in black consumers could reflect higher overall consumption of fast food and/or different food choices among this population. Prior research suggests that predominately black neighborhoods in urban areas have a greater density of fast food restaurants than white neighborhoods.3
The authors point to PVC tubing, vinyl gloves used for food handling, and food packaging as possible sources of phthalate contamination in fast food. DEHP is a ubiquitous high-molecular-weight phthalate that has been removed from some products due to concerns about potential adverse health effects.5 In some cases it is being replaced with DiNP.2
The related Environmental Health Perspectives research article: Recent Fast Food Consumption and Bisphenol A and Phthalates Exposures among the U.S. Population in NHANES, 2003–2010
Experimental animal studies demonstrate that DEHP and DiNP have endocrine-disrupting properties because of their anti-androgenic effects on the male reproductive system (National Research Council 2008). Human exposure to DEHP has been associated with adverse reproductive, neurobehavioral, and respiratory outcomes in children (Braun et al. 2013; Ejaredar et al. 2015) and metabolic disease risk factors such as insulin resistance in adolescents and adults (James-Todd et al. 2012; Attina and Trasande 2015). Though epidemiologic evidence of DiNP is less complete, recent studies report associations between exposure and similar health outcomes including adverse respiratory and metabolic outcomes in children (Bertelsen et al. 2013; Attina and Trasande 2015). BPA is also a suspected endocrine disrupter, and experimental and human evidence suggest that BPA is a reproductive toxicant (Peretz et al. 2014). In addition, prenatal BPA exposure has also been associated with adverse neurobehavioral outcomes in children (Mustieles et al. 2015).
Given the concern over chemical toxicity, it is important to identify modifiable sources of exposure that may be targeted for exposure reduction strategies. Simulated exposure modeling, observational epidemiologic studies, and intervention studies all suggest that diet is an important exposure pathway for both high-molecular-weight phthalates and BPA.....Phthalates have been shown to leach into food from PVC in materials like tubing used in the milking process, lid gaskets, food preparation gloves, conveyor belts and food packaging materials (Cao 2010;Serrano et al. 2014). In fact, an intervention study reported that urinary BPA and DEHP were reduced by 66% and 53–56%, respectively, when participants’ diets were restricted to food with limited packaging (Rudel et al. 2011). Foods high in fat, such as dairy and meat, may be more contaminated by high-molecular-weight phthalates that are more lipophilic such as DEHP (Serrano et al. 2014). Fast food may be an important source of exposure to phthalates and BPA because it is highly processed, packaged, and handled.
Chemicals known as "forever chemicals" or PFAS have been in the news a lot recently. This is because PFAS (per- and polyfluoroalkyl substances) are in so many products that we all use, yet research is showing more and more health harms from them. Including to pregnant women and developing babies.
Unfortunately, unprocessed and minimally processed foods are more expensive than ultra-processed foods. So it wasn't surprising that socioeconomic levels (including income levels) made a difference - the lower the household income, the greater the average ultra-processed food intake.