People Eating Home-Cooked Meals Have Lower Levels of Harmful Chemicals in Their Bodies

You may want to reconsider how many times a week you eat out and what you eat, a new study has shown.
Marcia Wendorf

In a report just published by the journal Environmental Health Perspectives, four scientists from the Silent Spring Institute have analyzed the content of restaurant and fast food meals and determined that they contain chemicals that have been linked to cancer.


The chemicals are polyfluoroalkyls (PFASs). They are found in greaseproof and water-resistant packaging, and they are commonly found in:

  • Food packaging, such as microwave popcorn bags and fast food wrappers
  • Stain-resistant carpets, rugs, and furniture, including Scotchgard®, and waterproof clothing including GORE-TEX®
  • Non-stick cookware, including Teflon®
  • Outdoor gear that has a "durable water repellent" coating
  • Firefighting foams and ski wax.

The types of PFAS are:

  • Perfluorooctanoic acid (PFOA)
  • Perfluorooctane sulfonic acid (PFOS)
  • Perfluorononanoic acid (PFNA)
  • Perfluorodecanoic acid (PFDA)
  • Perfluorohexanesulfonic acid (PFHxS)
  • Perfluordecanoic acid (PFDeA).

Once inside the body, PFAS have a long half-life of up to eight years. Exposure has been linked to these health concerns:

The Silent Spring Institute, which is based in Newton, Massachusetts, was founded in 1994 to research the links between breast cancer and exposure to chemicals found in everyday products. The institute is named after environmentalist Rachel Carson who died of breast cancer in 1964. She was the author of the book Silent Spring, which documented the adverse environmental effects of pesticides.

Silent Spring
Silent Spring Source: Wikimedia Commons

What the researchers did

The scientists examined the amount of PFAS in the blood of over 10,000 people from the years 2003 to 2014 who were part of the National Health and Nutrition Examination Survey (NHANES). The survey tracks nutritional and health trends in the U.S.

They found that people who ate more meals at home had significantly lower levels of PFAS in their bodies. The home cooks sourced their food from grocery stores. People who ate more frequently at restaurants or consumed more fast food, including pizza, had higher levels of PFAS in their bodies.

This suggests that restaurant food and fast food are more likely to be contaminated with PFAS due to their greater contact with PFAS-containing food packaging.

During the time period of 2003 and 2014, long-chain PFAS were most common. Manufacturers have been replacing long-chain PFAS with shorter chain varieties, but research has shown that they raise similar health concerns, leading experts to call for restrictions on this entire class of chemicals.

Fast food packaging

In 2017, the Silent Spring Institute studied the greaseproof packaging used by fast food companies. They tested over 400 samples from 27 fast food chains throughout the U.S., including paper wrappers, paperboard, and drink containers.

As reported in the February 1, 2017 issue of the journal Environmental Science & Technology Letters, the researchers found that almost 50% of paper wrappers and 20% of paperboard samples, such as boxes for fries and pizza, contained fluorine, a marker for the presence of PFAS.

In particular, Tex-Mex food packaging, dessert and bread wrappers were the most likely to contain fluorine.

Of the report, researcher Laurel Schaider said, "Children are especially at risk for health effects because their developing bodies are more vulnerable to toxic chemicals." According to the National Center for Health Statistics, approximately one third of children in the U.S. consume fast food every day.

Two university studies

In a 2018 study, researchers at George Washington University and the University of California Berkeley at San Francisco found that people who regularly ate at restaurants, cafeterias and fast food places had had PFAS levels that were 35% higher than those who ate food purchased at grocery stores.

The team found that:

  • The association between phthalate exposure and dining out was significant for all age groups, but the highest for teenagers
  • Adolescents who ate fast food and other food purchased outside the home had 55% higher levels of phthalates  compared to those who only consumed food at home
  • Sandwiches, such as cheeseburgers, were associated with 30% higher phthalate levels in all age groups.

According to a recent study by the National Center for Health Statistics, 36.6% of U.S. adults, or about 85 million people, ate fast food, including pizza, on a given day. For people between the ages of 20 and 39, that figure rose to 44.9%, and for people age 40 to 59, it was 37.7%. Of those age 60 and older, only 24.1% ate fast food daily.

Surprisingly, fast food consumption increased with income level, with 42% of those in the high-income range eating fast food once a day.

On April 1, 2019, the U.S. Centers for Disease Control and Prevention (CDC) announced plans to conduct a health study of PFAS. According to the agency’s draft planning document, the study will examine renal function and kidney disease, thyroid hormones and disease, liver function and disease, diabetes, and immune response and function in both children and adults.

Strangely, the study will not examine whether exposure to PFAS can cause cancer.

How can you reduce your exposure to PFAS?

You can take the following actions to reduce your PFAS exposure:

  • Avoid greasy or oily packaged and fast foods because the packaging often contains grease-repellent coatings, examples include french fry and pizza boxes.
  • Instead of eating microwave popcorn, make it the old fashioned way on your stove top.
  • Choose furniture and carpets that aren't marked "stain-resistant", and don’t apply coatings such as Stainmaster®.
  • Avoid waterproof and stainproof clothing and shoes, luggage and camping and sporting equipment.
  • Avoid personal-care products containing ingredients labeled "fluoro" or "perfluoro", PFCs are found in dental floss, nail polish, facial moisturizers, and eye make-up.
  • Avoid Teflon™ or non-stick cookware, but if using, be careful not to let it heat to above 450ºF; discard cookware immediately if the non-stick coatings show signs of deterioration.

For more information on PFAS, you can contact the Agency for Toxic Substances and Disease Registry.

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