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A recent study investigated levels of hormone-disrupting chemicals in popular fast foods. Zak Nuttall/500px/Getty Images
  • Phthalates are a class of plasticizers that manufacturers use to make plastic materials softer and more flexible.
  • Phthalates are present in food packaging and food processing equipment and can leach into food.
  • Exposure to phthalates can interfere with the function of hormones and have adverse health effects.
  • Replacement plasticizers are being increasingly used to reduce exposure to phthalates, but there is little understanding of their long-term effects on human health.
  • A recent study reports detectable levels of several phthalates and replacement plasticizers in popular food items from leading fast-food chains, highlighting the need for regulating these chemicals.

Plasticizers are chemicals that increase the flexibility and softness of materials.

Ortho-phthalates, or simply phthalates, are a class of plasticizers that manufacturers use to enhance the softness and durability of polyvinyl chloride (PVC) and other plastics.

Phthalates are a common ingredient of PVC food packaging items, such as the lining of food containers. These plasticizers are also used in food processing equipment and food preparation materials, such as gloves.

Phthalates can leach into food during food processing, preparation, and handling. While phthalates are ubiquitous and present in medical devices, toys, clothing, and personal care products, experts believe that diet is one of the major sources of exposure.

Phthalates, such as di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP), are endocrine disruptors.

Endocrine disruptors can interfere with the function of hormones by mimicking or blocking their effects or disrupting the production of hormones and their receptors.

Phthalates such as DnBP and DEHP can interfere with the activity of thyroid hormones and steroid hormones, including estrogen and testosterone.

Consequently, exposure to these phthalates plays a role in developmental, reproductive, and metabolic disorders. For instance, scientists associate exposure to phthalates with reduced sperm count, lower fertility in both males and females, obesity, and attention deficit hyperactivity disorder.

Fast-food items are highly processed, involving the use of prepackaged food items and several steps of preparation. Consistent with the increased likelihood of exposure to food contact materials, research links consumption of fast food with higher levels of phthalates in urinary samples.

To further assess the contribution of fast-food consumption to plasticizer exposure, a recent study assessed the concentration of plasticizers in popular food items from fast-food chains in the United States.

The study appears in the Journal of Exposure Science & Environmental Epidemiology.

Due to the growing awareness of the potential health risks of phthalates, manufacturers have started using non-phthalate replacement plasticizers in commercial products.

Some of the commonly used replacement plasticizers include di(2-ethylhexyl) adipate (DEHA), 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), and dioctyl terephthalate (DEHT).

As these replacement plasticizers have become more prevalent, researchers have observed an accompanying increase in the levels of breakdown products of these plasticizers in urine samples among the general U.S. population.

Although scientists consider these replacement plasticizers to be safer than phthalates, most of the evidence on the safety of the former comes from just a few animal studies.

Evidence from human studies on the long-term consequences of chronic exposure to these replacement plasticizers has been unclear and therefore raises concerns about the safety of these chemicals.

The present study reports detectable levels of both phthalates and the three aforementioned replacement plasticizers in popular food items, as well as in gloves used in food preparation, from major U.S. fast-food restaurants.

Additionally, the researchers assessed the potential toxicity of the replacement plasticizers using laboratoryassay data generated by the Environmental Protection Agency (EPA) database. Their preliminary analysis revealed that exposure to these replacement plasticizers could potentially lead to adverse health effects.

Medical News Today spoke with Dr. Stephanie Engel, an epidemiologist at the University of North Carolina at Chapel Hill, who was not involved in the study,

“This is a very important study, because it documents the presence of multiple phthalates in commonly consumed fast-food items, like hamburgers and chicken nuggets.”

“Previous research has found that people who report greater consumption of fast food have higher levels of phthalates in their urine,” she continued. “This current study looks directly at fast food and materials used in fast-food preparation to determine where exposure is coming from.”

In the present study, the researchers assessed the levels of eight phthalates and three replacement plasticizers in popular fast foods sampled from six leading fast-food chains located in San Antonio.

They collected a total of 64 food samples from two or three separate locations of each of the six fast-food chains. The researchers also collected unused gloves from three fast-food restaurants.

The fast-food chains included in the study were McDonald’s, Pizza Hut, Taco Bell, Burger King, Domino’s Pizza, and Chipotle.

The researchers quantified plasticizer levels in hamburgers, chicken burritos, french fries, chicken nuggets, and cheese pizzas from these outlets.

Overall, the researchers found detectable levels of plasticizers in all 64 food samples. Out of the 11 plasticizers under consideration, they detected seven out of eight phthalates and all three replacement plasticizers.

The phthalates DnBP and DEHP and the replacement plasticizer DEHT were most frequently detected in the fast-food samples.

The researchers found detectable levels of DnBP and DEHP in 81% and 70% of the food samples, respectively. DEHT was detected in 86% of all food samples, whereas DEHA was present in 41% of the fast-food items.

Moreover, food items containing meat had a tendency for a higher concentration of plasticizers than those without meat. For instance, hamburgers and burritos had high levels of plasticizers, whereas cheese pizzas had the lowest plasticizer levels.

The authors found particularly high levels of the replacement plasticizer DEHT in burritos and hamburgers but not in fries.

The higher levels of DEHT in hamburgers and burritos than in fries may be due to the greater assembly and handling involved during the preparation of these food items. This finding suggests that food preparation materials, such as gloves, could be one of the sources of exposure to these replacement plasticizers.

Although phthalates were not detected in gloves, these replacement plasticizers, including DnBP and DEHP, were present in high concentrations in the fast-food items. This suggests that contamination of the fast-food items with phthalates may occur during food processing or due to the packaging materials.

These results show that known endocrine disruptors, such as DnBP and DEHP, are present in detectable levels in fast-food items from leading restaurants. Moreover, these food items contain high concentrations of DEHT and other replacement plasticizers, whose long-term health effects scientists do not yet understand well.

To assess the potential toxicity of the replacement plasticizers DEHA, DINCH, and DEHT, the researchers obtained data on assays involving these chemicals generated by the EPA research program ToxCast.

The ToxCast program uses high-throughput screening, which deploys automated techniques to rapidly conduct in vitro assays on a large number of compounds, to collect toxicity data on chemicals.

Using the data collected from the ToxCast assays, the researchers found that each of the three replacement plasticizers could activate or inhibit specific nuclear receptors, including those for steroid hormones.

For example, data from one of the ToxCast assays suggest that DEHA is able to block one of the estrogen receptors — estrogen receptor alpha.

These receptors play a vital role in regulating a number of biological processes. The analyses of the ToxCast data thus suggest that exposure to replacement plasticizers could potentially have adverse health effects, similar to those observed in phthalates.

The authors note that this is “the first study to quantify concentrations of phthalates and replacement plasticizers in foods and gloves from U.S. fast-food chains and the first to detect DEHT in foods.”

The study has other salient features as well. The study’s first author, Dr. Lariah Edwards, a postdoctoral researcher at the George Washington University, explained to MNT, “We sampled foods and gloves from the same restaurants to explore gloves as a potential source of phthalates and replacement plasticizers exposure.”

However, the authors concede that the study had a few limitations. Dr. Edwards explained: “We only sampled gloves from three restaurants instead of all six restaurants. Additionally, we recognize that the characterization of chemicals in collected gloves lacked precision. For example, we were only able to detect chemicals present in gloves at high concentrations due to limitations in how we analyzed the glove samples.”

“We only sampled foods from restaurants in one city. While we generally didn’t observe differences in the chemical concentrations between different restaurants and locations of restaurants, we recognize that the small number of restaurants slightly limits the generalizability of our results,” Dr. Edwards added.

Numerous studies have found racial disparities in health outcomes, with Black people having higher rates of chronic diseases and all-cause mortality rates than white people.

Residential segregation along racial lines, although often ignored, plays a key role in mediating these health outcomes.

Some of the factors experts associate with residential segregation that influence health outcomes include access to medical care, educational and employment opportunities, and exposure to environmental pollutants.

Black neighborhoods in the U.S., regardless of income levels, also tend to have a higher density of fast-food restaurants than white neighborhoods.

Consequently, Black people may experience more exposure to phthalates and other plasticizers. Moreover, the study authors previously reported a stronger association between intake of fast food and phthalate exposure in Black people.

When speaking to MNT, Dr. Engel explained: “This study raises an important issue of health equity as well. Because some racial and ethnic minorities have previously been shown to have higher levels of some phthalates in their bodies, and fast-food restaurants are found in higher frequency in low income neighborhoods that have a higher proportion of racial and ethnic minorities, chemical exposures from fast food may be an important contributor to these disparities in exposure across populations.“

The omnipresence of materials containing phthalates and other plasticizers makes it impossible to avoid contact with these substances.

“Exposure to phthalates in the general population is widespread, and in the U.S., there are very few regulations in place to protect consumers,” Dr. Engel elaborated.

“We suspect diet is a major source of exposure to phthalates, but this exposure pathway is very complex. Contamination with phthalates can happen upstream, during food production, as well as downstream, during food preparation.”

“Because phthalates can be found in so many different materials that come into contact with food,” Dr. Engel continued, “it is very difficult for an individual to avoid exposure through intentional choices or behaviors. Phthalates also come from many other sources, including personal care products, like cosmetics, shampoos, and lotions, to materials in your home, like vinyl window covers or shower curtains. That’s why we refer to phthalates as ‘everywhere chemicals.’”

This highlights the need for robust regulations that restrict the use of plasticizers, such as phthalates, in food contact materials.

“Regulation of phthalates has been minimal in the U.S., with the exception of a ban on eight phthalates in children’s toys. The Food and Drug Administration (FDA) has the legal authority to regulate phthalates in food. However, in spite of significant health risks, the agency has thus far refused to withdraw its approval for the 28 phthalates it currently allows as food additives in food contact materials.”

– Dr. Stephanie Engel

Dr. Edwards similarly observed: “The way phthalates are regulated does not make sense. Phthalates are not regulated in cosmetics or food contact materials. Only some have been banned from children’s toys. Stronger regulations are needed to help keep all phthalates and replacement plasticizers out of our foods.”