Restaurant diners may ingest extra pollutants | Science News for Students

Restaurant diners may ingest extra pollutants

Eating meals cooked at home was linked to lower body levels of certain hormone-meddling chemicals
May 29, 2018 — 6:45 am EST
Teen pizza

Teens who downed restaurant, cafeteria or carryout food in the past day had far higher levels of certain potentially harmful chemicals in their bodies than did teens who ate only home-cooked meals.


Dining out may boost exposure to certain potentially toxic pollutants, a new study finds. Researchers measured higher levels of these phthalates (THAAL-ayts) in the bodies of people who recently dined out than in those who had been eating only foods that had been cooked at home.

Phthalates are found in many products, notably cosmetics, floor tiles and certain types of plastics. These chemicals also are used in food packaging. Many studies over the past few decades have shown phthalates can mimic the action of certain hormones. (Such pollutants are known as endocrine disruptors.) Hormones are important chemicals that help direct the activity of cells throughout the body. The effects of phthalates on hormones may alter how reproductive organs develop in infants and children. These chemicals might even impact the timing of puberty, animal studies have shown. That’s why environmental scientists recommend limiting exposures to phthalates.

Yet doing that isn’t easy. Why? Phthalates are everywhere — in the air, water and soils. They are the most common industrial pollutant in the environment. People inhale and ingest tiny quantities every day. These pollutants can even enter the body through the skin.

Ami Zota is an environmental health scientist at George Washington University in Washington, D.C. She studies how pollutants can affect health. And her team knew that food packaging can be a notable source of exposure to some phthalates.

“We all know that certain foods are more nutritious than others. But there are other ways that food choices can affect health,” says Zota — and in a potentially negative way. That’s why her team wanted to look for any trends between where people get their food and the amounts of phthalates in their bodies. Such information could be important, she says, in guiding the behaviors of people who want to limit their exposure to phthalates.

To find out where people were eating, the researchers tapped into results from a large national survey. Known as the National Health and Nutrition Examination Survey, it included data collected between 2005 and 2014 from more than 10,000 U.S. children, teens and adults. It asked each person what they had eaten in the past 24 hours. Each participant also provided a urine sample.

At least six in every 10 of these people (61 percent) reported dining out at least once in the past day. Such meals might have been purchased in a cafeteria, from a fast-food place or in a sit-down restaurant. Children and teens ate out more than adults did. Teens were more likely to eat fast food. Younger children were more likely to eat cafeteria food. Adults over age 60 were most likely to report having eaten at home only.

The researchers compared such data to levels of phthalates found in someone’s urine. People who reported eating out in the past day had 35 percent more phthalates in their urine compared with people who ate only food purchased at a grocery store. Among teens, phthalate levels in those who dined out were 55 percent higher than in teens who had eaten only food from home.

The new study’s findings are concerning, Zota’s team says. People are dining out more than ever. That could mean ever higher exposures to these pollutants.

The researchers reported their findings March 29 in the journal Environment International.

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Food can be a major source of exposure to phthalates. Children and teens who reported recently dining out had higher levels of these chemicals in their bodies than did those who had been eating only food from home.

Why do these pollutants taint food?

Certain types of foods were linked more strongly than others to phthalate levels in the body. But some foods were linked to these pollutants only when they had been purchased in a restaurant or cafeteria. Among these were cheeseburgers and sandwiches.

That could be due to food wrappers, says Laurel Schaider. She’s an environmental chemist at the Silent Spring Institute in Newton, Mass. She studies how chemicals in food packaging pollute the environment and people.

When you make a burger or sandwich at home, you probably put it on a plate and eat it right away, she notes. When cafeterias or fast-food restaurants make these foods, they tend to wrap them in paper, plastic or cardboard. Such wrappers keep oils from seeping onto your hands or lap. Those wrappers may be treated with certain chemicals, such as phthalates, to limit that oil bleed-through, Schaider explains.

For instance, one British study in the 1990s found that up to 500 micrograms of di-n-butyl phthalate (DBP) could migrate into each kilogram of food packaged in plastic wrap. Butyl benzyl phthalate (BBP) goes into many papers and wrappings designed to make contact with liquids, dry materials and fatty foods. In fact, some studies have found up to 45 milligrams of BBP in each kilogram of wrapped butter and margarine.

“This study provides pretty clear evidence that we can be exposed to phthalates through the foods that we eat,” says Schaider. But there are still many more questions to answer. “We want to know whether people with the highest levels of phthalates experience any health effects as a result of these exposures,” she says.

Future studies also could help pinpoint the biggest sources, Schaider notes. Certain types of restaurant equipment or food packaging might prove more likely to leach phthalates.

Such information may one day help policymakers design laws to reduce phthalates in food, adds Zota.

In the meantime, concerned diners can take their own steps to reduce their exposure to these potentially harmful chemicals. One way is by choosing home-cooked meals over restaurant food. “The body excretes phthalates pretty quickly,” Schaider says. As such, she explains, any change you make to your diet “can affect exposure levels right away.”

Power Words

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adolescent     Someone in that transitional stage of physical and psychological development that begins at the onset of puberty, typically between the ages of 11 and 13, and ends with adulthood.

behavior     The way something, often a person or other organism, acts towards others, or conducts itself.

cell     The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.

chemical     A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.

development     (in biology) The growth of an organism from conception through adulthood, often undergoing changes in chemistry, size and sometimes even shape. 

diet     The foods and liquids ingested by an animal to provide the nutrition it needs to grow and maintain health. (verb) To adopt a specific food-intake plan for the purpose of controlling body weight.

environment     The sum of all of the things that exist around some organism or the process and the condition those things create. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature and humidity (or even the placement of components in some electronics system or product).

environmental health     A research field that focuses on measuring the effects of pollutants and other factors in the environment on the health of people, wildlife or ecosystems.

excrete     To remove waste products from the body, such as in the urine.

hormone     (in zoology and medicine) A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body. (in botany) A chemical that serves as a signaling compound that tells cells of a plant when and how to develop, or when to grow old and die.

ingest     (n. ingestion) To eat or deliberately bring nutrients into the body by mouth for digestion in the gut.

leach     (in geology and chemistry) The process by which water (often in the form of rain) removes soluble minerals or other chemicals from a solid, such as rock, or from sand, soil, bones, trash or ash.

migrate     To move long distances and across boundaries (such as across the skin) to some new site.

National Health and Nutrition Examination Survey     (or NHANES) A long-running program (begun in the early 1960s), which has been designed to assess the health and nutritional status of adults and children in the United States. NHANES combines both physical (medical) examinations and interviews. It’s run by the National Center for Health Statistics, which is part of the U.S. Centers for Disease Control and Prevention. Each year, the program surveys another 5,000 people who have been chosen to be representative of all ages and races, and of people living throughout the nation.

organ     (in biology) Various parts of an organism that perform one or more particular functions. For instance, an ovary is an organ that makes eggs, the brain is an organ that makes sense of nerve signals and a plant’s roots are organs that take in nutrients and moisture.

phthalates     A family of chemicals used as solvents and added to plastics to increase their flexibility.

plastic     Any of a series of materials that are easily deformable; or synthetic materials that have been made from polymers (long strings of some building-block molecule) that tend to be lightweight, inexpensive and resistant to degradation.

pollutant     A substance that taints something — such as the air, water, our bodies or products. Some pollutants are chemicals, such as pesticides. Others may be radiation, including excess heat or light.

puberty     A developmental period in humans and other primates when the body undergoes hormonal changes that will result in the maturation of reproductive organs.

reproductive organs     The organs in a creature’s body that allows it to make and deliver eggs or sperm, and where appropriate, to nurture developing eggs and fetuses.

survey     (v.) To ask questions that glean data on the opinions, practices (such as dining or sleeping habits), knowledge or skills of a broad range of people. Researchers select the number and types of people questioned in hopes that the answers these individuals give will be representative of others who are their age, belong to the same ethnic group or live in the same region. (n.) The list of questions that will be offered to glean those data.

taint     To contaminate.

toxic     Poisonous or able to harm or kill cells, tissues or whole organisms. The measure of risk posed by such a poison is its toxicity.


Journal: J.R. Varshavsky et al. Dietary sources of cumulative phthalates exposure among the U.S. general population in NHANES 2005-2014. Environment International. Published online March 29, 2018. doi: 10.1016/j.envint.2018.02.029.