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Feb 28, 2011 09:07 AM

Non stick cookware a cause of thyroid damage/disease?


"PFCs may be found on a number of common products, including non-stick cookware, stain-resistant carpets and rugs, breathable fabric and certain food packages, according to the Seattle-based news source.

It added that a recent study associated high blood levels of PFCs with an increased incidence of certain thyroid conditions.

The research, published in the journal Environmental Health Perspectives, determined that individuals with high levels of two forms of PFC - called perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate - were more likely to currently have a thyroid disease.

In particular, women who had more than 5.7 nanograms of PFOA in each milliliter of blood (ng/mL) were more than twice as likely to have hypothyroidism or thyroid cancer than those with levels lower than 4 ng/mL...."

  1. mcf: Thanks for the link. Yet another reason to avoid nonstick. Would PFC-caused thyroid problems be a *known unknown* now?

    But you will also get a lot of dismissive criticism on this, e.g., "no peer-reviewed studies linking blood levels with *cookware*", etc., etc. I'm for erring on the side of caution.

    26 Replies
    1. re: kaleokahu

      You're welcome. I don't have a dog in this fight, just some information to share that I came across today while searching for something else.

      1. re: kaleokahu

        PFOA is used during the making of PTFE (Teflon), however it's not one of the chemicals *in* PTFE. That said, some manufacturers are a bit sloppy and some PFOAs do make their way into finished products.

        Now, if you're at all worried about PFOAs, non-stick cookware is the least of your worries. You should be worrying about stain resistant carpets, waterproof or water-resistant clothing (Gore-Tex ski jackets, anyone?), and microwave popcorn bags.

        What's in your waxed paper? Up to 1100 times as much as in your non-stick cookware. How about the sealant for your tile floor? Up to 700 times as much as in your cookware. Plus since you heat your cookware, any residual PFOAs are driven off and out the hood vent the first time you use your cookware.

        If you're concerned enough to not use non-stick, you also need to be 1000 times as concerned about many other common products around the house.

        1. re: ThreeGigs

          Actually, I don't have any wall to wall carpets (can't get the filth out from under them) or non natural wool rugs in my house, nor will I ever. Nor microwave popcorn bags. But you fail to distinguish between things used with intense heat, causing them to seriously out gas, vs. less vaporous uses. I don't sleep on no iron sheets, either. :-)

          1. re: mcf

            >I don't sleep on no iron sheets, either.<

            + 1

          2. re: ThreeGigs

            3G: "What's in your waxed paper? Up to 1100 times as much as in your non-stick cookware. How about the sealant for your tile floor? Up to 700 times as much as in your cookware."

            What's the evidence for this, and how was *that* quantified?

            "Plus since you heat your cookware, any residual PFOAs are driven off and out the hood vent the first time you use your cookware."

            I'm unconvinced all residual chemicals are gone after one use. And we're not talking laboratory fume hoods/gloveboxes equaling range hoods, either.

            If there's only a *little* extra exposure to PFOA (and God knows what else), that's OK? Feel the same way about mercury?

            1. re: kaleokahu

              "If there's only a *little* extra exposure to PFOA (and God knows what else), that's OK? Feel the same way about mercury?"

              Kaleo. Mercury is toxic, but probably not as toxic as some believe -- not in the elemental form. There was a man who drank 220 mL of mercury (3 kg) of mercury and survived:


              Mercurcy is more toxic in its complex forms, as inorganic salt or organic.

              Just because something is toxic in high dose, it does not mean it is slightly toxic at low dose. It is not like that. If so, you can forget about taking any pill because every pill has a tox dose. Also forget beer and wine because of the toxicity of ethanol.

              Aspirin (acetylsalicylic acid), a very safe drug, has a tox dose too. It has an acute oral LD50 dose for rats at 200 mg/kg. The human LD50 is estimated to be 357 mg/kg


              As for PFOA, the LD50 are 680 mg/kg for male CD rats and 430 mg/kg for female rats. As you can see, the oral lethal dose is higher than aspirin. In other words, you probably have a better chance killing me by shoveling aspirin down my thoart than PFOA. Meanwhile, many people take daily aspirin from reducing heart attack to lowering breast cancer....

              Of course, I am not really arguing PFOA is better than aspirin.

              1. re: Chemicalkinetics

                "Just because something is toxic in high dose, it does not mean it is slightly toxic at low dose. It is not like that."

                It's not necessarily like that, but that doesn't mean low doses aren't at all harmful, often cumulatively, slowly over time where the damage is rarely recognized as caused by the drug. Same with moderate alchohol consumption done habitually...

                I think you may be failing to distinguish between acute poisoning vs. chronic low level harm. And also the fact that non stick coatings do nothing to improve one's quality of life or health and some medications do.

                1. re: mcf

                  "It's not necessarily like that, but that doesn't mean low doses aren't at all harmful"

                  And it does not mean low doses are harmful neither. We don't automatically assume something is toxic unless there are good evidences. How did FDA approve aspirin? Was there a 30 years study before the drug got approved? No. Moreover, nonstick cookware is not considered as the main source of these compounds according to research articles.

                  "I think you may be failing to distinguish between acute poisoning vs. chronic low level harm."

                  You may fail to understand there is no known published chronic tox dose for PFOA, so how can I talk about something which is unknown? This is why I discussed the acute doses and I specifically spelled out these are acute doses.

                  1. re: Chemicalkinetics

                    You keep arguing statements I haven't made, so have at it. :-)

                  2. re: mcf

                    "non stick coatings do nothing to improve one's quality of life"

                    I beg to differ. The less I have to scrub anything, the better my quality of life is.

                  3. re: Chemicalkinetics

                    Chem: Your aspirin analogy couldn't be more inapt. Yes, taking too much can kill you, but taking the *right* amount can be beneficial. As far as I know, there is NO good reason for ingesting PFOA. It's just our ghoulish friends convenience and money rolling dice and trying to keep nerdy medicine and epidemiology drunk.

                    You're also backing into one of the big rhetorical fallacies that usually gets played here in these threads whenever anyone mentions PTFE and bird deaths. The fallacy goes: Birds are different; since no humans are dropping instantly dead from breathing PTFE cookware offgassing, it must be safe. Below-threshold toxicity can also have terrible cumulative health consequences.

                    Finally, just because *someone* survives a profoundly toxic dose of something is not really probative of much. I knew a hale 98-year-old who smoked 2 packs of unfiltered cigarettes every day for 80 years. Is the WW2 veteran's weekly de-lousing in DDT powder in 1943 the cause of his bone cancer in 2003? Would he take the same risk that it was, again?

                    We're (none of us) as smart as you make it seem, sometimes. Sometimes it's better to err toward caution.

                    1. re: kaleokahu


                      Like I wrote, I wasn't really arguing that PFOA is better than aspirin. I probably didn't spell it out more clear. What I wanted to use the aspirin analogy to show is that the "toxicity effect-to-dose" relationship is not linear. Just because 50% of the rats die at 350 mg/kg. It does not mean 175 mg/kg will kill 25% and 7mg/kg will kill 1%. It is not linear. That was my point. Consequently, I was trying to answer your question of "If there's only a *little* extra exposure to PFOA... that's OK?"

                      Yes, it probably is OK. If the aspirin analogy still does not resonate, then thinks wine. Drinking 1 glass of wine a day does not have 1/5th of the toxicity of drinking a bottle a day. When it comes to toxicity, it is never linear to dose.

                      P.S.: "As far as I know, there is NO good reason for ingesting PFOA. It's just our ghoulish friends convenience and money rolling dice"

                      Good point, but you know copper is toxic :) I don't remember you use the same level of passion argue against copper cookware? The argument that high dose of copper is toxic, so even trace level is dangerous in long-term (chronic)... No good reason for ingesting copper... err on the caution and stay away from copper..etc.

                      1. re: Chemicalkinetics

                        Chem: Actually, a very low dose of copper is healthy, but I do not advocate cooking or storing acidic foods in uncoated copper. Tin even more so.

                        I get your point about nonlinearity. My point is that PFOA is very highly probably a carcinogen, and we don't know even IF there is a *safe* dose. So we can't "weigh", "judge", etc. what a safe dose is. How many years was it before the xylenes and other nasties in paint solvents got recognized as being so bad we shouldn't tolerate ANY outside a controlled environment?

                        If it was given, I also missed the answer to what, in plain parchment paper, contributes PFOA or PFOS. Do you know?

                        1. re: kaleokahu


                          Yes, I agree. PFOA is neither copper nor aspirin. Copper is nowhere as toxic as PFOA and our bodies have high clearance of copper -- copper is quickly removed. Even if you overdose in copper, as long as you don't continue to keep ingesting copper, the copper level in your blood should come down very fast. PFOA has a much longer lifetime - years. Actually, originally my point is to say that most of us probably ingest more copper from our copper coated pennies than from any copper cookware. Getting rid of pennies probably is more productive than removing copper cookware. I am just not sure if Teflon cookware is the main source of our PFOA. I actually don't have Teflon cookware anyway. I do have Teflon bakeware, just because it is so difficult to uncoated bakeware.

                          As far as I know, the parchment paper does not have anything to do with Teflon or PFOA... etc. It should be just silicone, like those silicone utensils. Mikie may know more because this is more about polymer chemistry and polymer process.

                          1. re: Chemicalkinetics

                            Hi, Chem: Totally OT, but why would plain parchment paper have silicone in it? For that matter, does anyone know for sure whether waxed paper has anything other than wax?

                            1. re: kaleokahu

                              " Totally OT"

                              What is 'OT'?

                              If we talking about parchment paper for baking, then silicone is used for the nonstick and water resistant properties. It is not some intermediate or trace compound. It is the intentional main component for many (not all) parchment papers.

                              1. re: Chemicalkinetics

                                Chem: OT = Off Thread.

                                And here I thought parchment paper was just paper.

                                Are you sure you're (and others are) not talking about the coated paper called "bakery release paper"? Now *that* would make sense if it was coated with PTFE and was a source of PFOA when cooked on. Or silicone.

                                Weren't chefs using parchment before 1900?

                                1. re: kaleokahu

                                  Check the Wiki article on parchment paper - there are 2 types; one just treated with the sulfuric acid bath, the other coated with silicone. Most likely, what you have in the kitchen is coated.

                                  1. re: paulj

                                    paulj: There is no coating apparent on mine. In fact, both sides look identical. I inherited a lifetime supply of large sheets about 10 years ago from a chef who retired.

                                    How would you tell if it's coated or not other than by looking?

                                    1. re: kaleokahu

                                      I would go by the labeling on the box. if 10 yrs old, and no 'now with silicone' or 'non stick', then it may just have the acid treatment. I don't think you can tell by looking; certainly not by comparing one side to the other (there's not right-side up for silicone paper).

                                      Paper making is chemically intensive. I don't know what residues are left in paper itself. Kraft paper, as used in grocery bags, may have the least chemical processing. But that does not mean it has been FDA approved to direct contact with food. Whiter paper will have bleaching of some sort done. Shiny paper has some sort of coating, such as a clay (for glossy magazine pages).

                                    2. re: paulj

                                      Yep (to the sulfurized cross link), which is why Mikie would know a lot more about it. Not even sure if these cross links are actually "safer" than silicone.

                        2. re: kaleokahu

                          The only way to err towards caution is to live in a hermetically sealed box. Preferably made of gold, as it has a fairly low reactivity with humans. Shame about the lack of air, water and food.

                          1. re: Shazam

                            Yannow, I think there's probably a middle ground somewhere between caution and paralysis by fear that you've overlooked. :-)

                            1. re: Shazam

                              Shazam: The "only" way? Really? How about erring on the side of caution by not using PTFE-coated cookware?

                          2. re: Chemicalkinetics

                            What's in parchment paper? any idea cause I put that s**t on everything, no really I couldn't resist that , what is in it?

                            1. re: Dave5440


                              They are not Teflon. :) Some parchment papers are made with silicone, some with sulfurized cross link polymer chemistry which Mikie knows a lot more than I do.


                    2. The article cites the Seattle PI. The PI no longer has a print edition. This item appeared in reader blog on Natural Medicine. It is not a regular news article. The author is a ' naturopathic physician and resident at Bastyr Center for Natural Health'.

                      I could not find a related article at . There are some recent thyroid articles, but they seem to be more concerned with flame retardants. I suspect the worries about non-stick pans come from this Bastyr author, not the authors of the NIH published studies.

                      I vaguely recall a discussion on along this line in the Media section, possibly in the past year.

                      1 Reply
                      1. re: paulj

                        It seems to come from data collected by the U.S. Centers for Disease Control and Prevention and NHANES data analysisby British researchers:


                      2. Isocyanates in car paints.
                        Benzene produced from your BBQ and well, just cooking.
                        Xylene from paints (all paints, even low-VOCs).
                        Formaldehyde from hardwood floors.
                        Aluminum in the clear coat on your hardwood floors.
                        The few thousand carcinogens from cigarette smoke.
                        Carcinogens formed from cooking, especially anything involving high heat (sauteing, baking, BBQing, etc)
                        Oxalic acid in spinach.

                        Repeat to yourself: The dose makes the poison.

                        Aspirin and acetaminophen cause thousands of poisonings each year.

                        1. People have died from overexposure to water. Plain old water, nothing in it.

                          So. You wanna scare me? Give me results from a large-sample, double-blind, peer-reviewed study NOT sponsored by anyone who has a vested interest in the results, and which has been duplicated at least once with similar results.

                          2 Replies
                            1. re: sunshine842

                              I'm pretty sure no one wants to scare you. :-)

                              And I don't think the U.S. Centers for Disease Control have vested interests in the results.

                            2. Isn't this another one of those "ick factor" issues? There is no way to know for sure how safe most things are (like this) due to individual sensitivities, flawed research, mis understood research, individual use/abuse patterns, etc. Just imagine the variability in manufacturing and products.

                              I live by the old saying, there is nothing certain in life - but death and taxes. I am always stunned to see so many people appear so certain of all kinds of very uncertain things! I say, choose your own battles. I don't use non stick cookware because I believe it is likely not a healthy daily choice. Also not a daily choice: florescent orange Cheeto's, BBQ, fast food and frozen snickers bars. I love all of those things once in a while, just not daily. Like the non stick cookware, daily use would give me an "icky" feeling.

                              1 Reply
                              1. re: sedimental

                                sedimental: Very well said.

                                Of note here is that no one in this thread has said PTFE cookware *does* cause cancer or anything else bad. The "certainty" is expressed on the side of its safety, as if it were wrong to be uncertain of it.