Air Date: Week of November 6, 2009

Jessica Nelson MPH, lead study author and researcher at the Boston University School of Public Health

PFCs, or polyfluoroalkyl chemicals are everywhere — from Teflon pans to stain resistant carpeting and take-out food containers. A new study shows a strong association between these chemicals and increased human cholesterol levels. Host Jeff Young talks with the lead author of this study, Jessica Nelson, a public health researcher at Boston University’s School of Public Health.

Transcript

YOUNG: It's Living on Earth, I'm Jeff Young. Two new studies are raising concerns about some chemicals cholesterol. Polyfluoroalkyl chemicals or PFCs have a long history in common consumer products like Teflon, stain-resistant fabrics and even some food wrappers. PFCs made those products non-stick, but the chemicals do stick around in our bodies, and it could be raising cholesterol. Health researcher Jessica Nelson conducted one of those studies at Boston University’s School of Public Health. Ms. Nelson, welcome to the program.

NELSON: Thank you, glad to be here.

YOUNG: Well, tell me about your results here. What did you learn about the link between these chemicals and cholesterol?

NELSON: Our study found that higher levels in blood of three of these PFC chemicals was associated with higher levels of bad cholesterol. And this was in a sample of the general U.S. populations.

YOUNG: So, this is not people whose drinking water was contaminated or who are working with these chemicals? This is me, you, everybody else?

NELSON: That’s right. And so the CDC conducts this survey, including testing people’s blood for PFC and other chemicals. So we were considering a population of the general U.S. population. Not workers who are highly exposed, not communities who are highly exposed from drinking water or other sources. And, virtually everyone tested we can detect these chemicals in their blood.

YOUNG: How are we exposed?

NELSON: Unfortunately, more research needs to be done. We really don’t understand very well the specific ways people are exposed. The likely pathways are through ingestion of food and drinking water. But, possibly also ingestion and inhalation of dust and air in homes. And basically products where chemicals are used to make them more stain, oil, water, grease-resistant. So, possible products are things like pizza boxes, takeout food wrappers, carpet treatments, textile treatments – it’s a pretty broad category of products that a lot of us encounter everyday.

YOUNG: So, generally speaking, what do these chemicals do when they get in our bodies? As I understand it, a lot of chemicals of concern build up in our fat deposits. But, that’s not necessarily the case with these, right?

NELSON: That’s true; they’re considered persistent chemicals but they aren’t lipophilic or building up in fat deposits like other ones you hear about like PCBs or dioxin. It looks like instead that they actually bind to proteins, so they might be binding to proteins in our blood, proteins in our liver, proteins in other tissues, and that’s why they’re sort of in our bodies for a number of years.

YOUNG: Well, give me an idea of the persistence, either in the environment or in our bodies.

NELSON: In the bodies, they have a half lives on the order of five years, so within five years time half of the chemical will excreted from the body. That’s a fairly persistent chemical, sort of compared to some other chemicals that we’re exposed to.

YOUNG: Now, this is just one of many red flags that researchers have raised about the potential health effects of these chemicals. And there were so many red flags, in fact, that some of the major users – DuPont, 3M, other companies – entered into this voluntary agreement with the U.S. Environmental Protection Agency to phase out the use of some of these. Does that mean that we’re not going to see these chemicals around anymore?

NELSON: Well, we have seen that blood concentrations are decreasing. But it doesn’t mean that we’re not going to see them anymore. First of all, as we’ve talked about, they’re persistent, so they stick around in our bodies for years. And, they also are persistent in the environment, so just because we stop them today doesn’t mean that they’re going to go away in the environment. There’s also a possibility that some other PFC chemicals that haven’t been phased out may actually break down into PFAS and PFOA– those are the two chemical and chemistries that are being phased out.

But not all of them have been eliminated, so one of the chemicals in our study that we did find this association with, PFNA, has not been phased out. And, in fact, we know that blood concentrations in people seem to be increasing for this chemical rather than decreasing.

YOUNG: So, what’s the potential health implication for me, you, for every other person who presumably has some of this stuff hitching a ride in our blood, in our livers – if it is indeed contributing to higher cholesterol?

NELSON: It’s a very good, and the most important question. One caveat that I want to give is that this is an exploratory study and there definitely are limitations to what we can say about it. It was an association study, so we really don’t feel we can say it’s a cause and effect relationship at this point. We know enough to know that we should be concerned and that we should aggressively pursue future research. But, unfortunately, it’s too early to sort of make that causal connection about your cholesterol levels or my cholesterol levels at this point.

YOUNG: Now, we reported back in 2006 on the settlement of this class action lawsuit against Dupont where folks in the area of the chemical plant were exposed to some of these chemicals via their drinking water. And the settlement was unique in that it set up this massive health-screening program. Is that health-screening effort, is that beginning to show us any results?

NELSON: So their population was highly exposed to one of the PFCs, PFOA, through their drinking water. So, the levels of PFOA are much higher than in our study. The levels of the other PFCs are similar. And from what I’ve seen they have consistent findings with what we saw. Namely, that higher levels of these PFCs are associated with higher total cholesterol and bad cholesterol.

YOUNG: And again, not a smoking gun – they can’t say conclusively, as you can’t say conclusively, but one study after another appears to be pointing in the same direction.

NELSON: That’s true, the same picture is emerging from these studies, but we haven’t quite addressed this fundamental limitation of a lot of the studies yet. But, it doesn't make sense to me that we should be exposing people to these PFC chemicals until we know they’re safe. And to me, from the research, I have seen this isn’t proven.

YOUNG: Jessica Nelson with the Boston University School of Public Health, thanks for coming by.

NELSON: Thank you.

 

Links

For a copy of the study, click here