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How Are Microwave Popcorn, Your Child’s Immune System Connected?

A freshly popped bag of microwave popcorn sits on a table; Photo by Justin Sullivan/Getty Images

After a dreary winter day, you come home, slip out of your cozy waterproof coat and boots, and get the kids started on their homework. For a snack, you pop some popcorn in the microwave and order a pizza for dinner. A pretty normal mid-January day, by most accounts. The last thing you’re thinking of, as you rush out the door to get the pizza, is your kids’ vaccination schedule.

But, a new study out today may change that.

It found that the perfluorinated compounds (PFCs) in these products are associated with lowered immune response to vaccinations in children. It is the first study to document how PFCs can adversely affect vaccine response. These pollutants can be transferred to children prenatally (via the mother) and postnatally from exposure in the environment.

PFCs have thousands of industrial and manufacturing uses, and most Americans have the chemical compounds in their bodies. Prior studies have shown that PFC concentrations in mice similar to those found in people suppressed immune response, but the adverse effects on people had been poorly documented.

For this study, researchers looked at children recruited at birth at National Hospital in Torshavn, Faroe Islands, located between Iceland and Norway, from 1999 to 2001. A total of 587 participated in follow-up examinations. Children were tested for immune response to tetanus and diphtheria vaccinations at ages 5 and 7 years. PFCs were measured in maternal pregnancy serum and in the serum of children at age 5 to determine prenatal and postnatal exposure.

The study appears in the Wednesday issue of the Journal of the American Medical Association (JAMA).

We spoke to lead author Philippe Grandjean on the phone last week. He’s an adjunct professor of environmental health at Harvard School of Public Health and the Chair of Environmental Medicine at the University of Southern Denmark.

Answers have been edited for clarity and length.

Tell us a little more about your study, and what it found.

Philippe Grandjean: What we found was that PFCs in the human body are associated with a deficient immune response to childhood immunizations. Children are less capable of maintaining an antibody concentration in the blood, which helps prevent getting the disease. The two vaccines we traced were tetanus and diphtheria.

How does this “pollution” happen? Where do children come in contact with these chemicals?

Grandjean: PFCs have been around for about 50 years. They’re in the environment, and we’re all exposed to them daily. They have been used for a long time for non-stick pans, and during this production, there’s some environmental pollution. And because these compounds are so stable, they stay in the environment for a long period of time. Once they come into your body, it also takes several years before you eventually excrete them.

We also come in contact with these chemicals in our food. Takeout pizza boxes and microwave popcorn bags are coated with these chemicals because of their non-stick properties. They’re also in our clothing — in waterproof jackets and sneakers, and also in the compounds in protectant sprays for upholstered furniture. Some of this ends up in indoor dust.

Are the non-stick pans we use to cook on in this category?

Grandjean: No. By the time you get the pan as a consumer, that whole surface has actually stabilized. If there’s any release of the PFC, it’s minimal. It’s during the production of that surface that is potentially harmful.

What causes the dip in the antibodies after exposure to PFCs?

Grandjean: It’s something that’s hard to examine in children. You can’t take out their lymph glands and examine them. But we do know from studies in mice that there are different mechanisms that appear to play a role, but it is unclear what exactly is going on. All we can say is that what we are observing in these kids is quite parallel to what has been observed in the mice. And the mouse is a very good model for the immune system.

How does this all relate to public health?

Grandjean: Well, you might say tetanus and diphtheria are not such big threats, but we think that because the responses were quite similar for the two vaccinations, they could very well represent the capability of the immune system to deal with vaccinations in general.

And if that is true, it means that the whole childhood immunization program that we rely on to protect the population from epidemics and infectious diseases might not be as efficient as we think. If some kids simply do not respond, if the vaccination doesn’t take, it means that some of the kids that we think are protected are not.

This study focuses on a relatively remote island sort of halfway between Iceland and Norway. Are the findings relevant to the U.S.?

Grandjean: The levels of PFCs in the children on these islands are actually slightly lower or just comparable to the U.S. levels. But the reason children have PFCs in their bloodstream in these islands is because of diet — they eat a lot of fish, and PFCs travel up the food chain that way. But in the U.S., it is more likely the pollution is from food packaging.

It’s important to note that this is just an observational study, and we cannot prove that there is a causal relationship. We need more studies.

But I also have a reaction as an individual, thinking about the next generation. We should take this very seriously because we are essentially looking at the tip of an iceberg. We have just looked at these kids at age 7, we don’t know yet how these immune deficits will eventually work out and how quick they will be at fending off, lets say, cancer. The immune system plays a very important role whether they will get chronic infections of various kinds.

We just don’t know. There are so many questions here, and the immune system is very complicated to study, but we have found this very clear and really strong signal that something is really going astray here.

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