Study raises concerns about food packaging

Is food packaging compromising the effectiveness of your child's vaccines?

A recent Harvard School of Public Health study suggesting that it might be has rocked parents and pediatricians nationwide.

The study looked at PFCs - perfluorinated compounds - a group of chemicals that are used in many kinds of food packaging.

They're useful because they resist heat, oil, stains, grease, and water. They keep the microwave popcorn inside the bag and the pizza cheese inside the box instead of leaking out and staining your car seat.

PFCs also are in clothing, furniture, and nonstick cooking surfaces.

But PFCs don't go away. They persist in the environment, including fish, and they're in us.

In a survey of more than 2,000 people, the Centers for Disease Control and Prevention found four different PFCs in the blood serum of nearly all of them.

The Harvard scientists, led by Philippe Grandjean, of the school's department of environmental health, decided to study 656 children born in the Faeroe Islands - in the Norwegian Sea between Scotland and Iceland - because the people there eat a lot of fish known to have lots of PFCs.

They looked at prenatal and postnatal exposure and then measured how well the diphtheria and tetanus vaccines worked at ages 5 and 7.

They concluded that when the postnatal exposure doubled, the "antibody concentration" in the child, an indication of the vaccines' effectiveness, was halved.

This was merely an association, not a cause, but "we believe that we have very strong evidence that there is something here that we need to be aware of," said Grandjean, a physician who is also associated with the University of Southern Denmark.

"Some of these kids had been vaccinated four times, and at age 7, they weren't even protected," he said. "This is mind-boggling."

No one is really worried about diphtheria and tetanus, as such, because they're so rare. But the vaccines are markers of the immune system's response to vaccines.

So even more worrisome, Grandjean said, is the possibility that the children's immune systems overall are sluggish.

The study was published in the Jan. 25 issue of the Journal of the American Medical Association.

Not everyone is rushing to ditch the microwave popcorn.

Paul Offit, who directs the Vaccine Education Center at Children's Hospital of Philadelphia, said he was disappointed in the study.

Suggesting that PFCs depress a child's response to a vaccine "is an extraordinary claim," he said. "And should be backed up by extraordinary evidence."

Offit felt the researchers should have made more of an effort to weed out other possibilities - "that those people with higher PFCs are less well-nourished, for example, and would not have as good an immune response."

"It's like saying that people with yellow hands are likely to get lung cancer, when it's the smoking that causes the lung cancer," Offit said.

Grandjean said they had done so, as much as possible.

They looked at birth weight, duration of breast feeding, age, gender, and time since the last immunization, as well as exposure to mercury and PCBs - other chemicals of concern that are common in fish.

"We did the best kinds of statistics that you can do, and we came up empty-handed," Grandjean said. "All we found was this strong association with PFCs."

Offit also said he didn't think two related studies the Harvard researchers cited lent enough plausibility to their conclusions.

In one, mouse immune systems were shown to be highly sensitive to some PFCs.

In another, human white blood cells in petri dishes were affected by the addition of PFCs. Signals they normally would have been sending to other cells to trigger a response to a foreign microorganism were inhibited.

Grandjean concedes: "You can always say, 'Yes, but.' Just because you can do this in a petri dish doesn't prove the point. On the other hand . . . I think this is very meaningful."

The Environmental Protection Agency recently reported "excellent progress" on a voluntary reduction program among companies that use PFCs. However, Grandjean noted that products from China still contain PFCs.

Meanwhile, Sen. Bob Casey (D., Pa.) was worried enough that he wrote to Health and Human Services Secretary Kathleen Sebelius, asking for officials to review the data and consider replicating the study.

In his own household, Grandjean intends to limit exposure to PFCs.

"But of course, it is difficult," he said. "Much of the consumer products, from microwave popcorn bags to rain gear, are not labeled."