Can The Cookware You Use Be Harmful To Your Thyroid Health?

Every now and then someone will ask me if the chemicals from the pots and pans they use can have a negative effect on their thyroid and immune system health.  And so I figured I’d put together a blog post that discusses the different types of cookware.  I’ll start out by talking about the safe types of cookware, and then I’ll talk about the ones you should avoid.  I’ll also discuss the relationship between some of these chemicals and thyroid/immune system health.  As usual, I’d love to hear your comments below, and so please feel free to let me know your thoughts on this post, the type of cookware you use, etc.

Also, keep in mind that I’m not necessarily listing the cookware in any particular order.  For example, when discussing the safest cookware, I’m going to start off with stainless steel, simply because this is what I use.  I’ll add that I wouldn’t be using it if I didn’t think it was safe, and while many other healthcare practitioners use stainless steel pots and pans, some prefer other types of cookware, such as ceramic.

Which Cookware is The Safest?

STAINLESS STEEL

Pros of stainless steel cookware.  As I just mentioned, this is what I use, and have used stainless steel for many years.  Stainless steel is very popular, as it’s cost effective, durable and long lasting, easier to clean when compared to some other cookware choices (i.e. cast iron), you can put it in the dishwasher without a problem, and good quality stainless steel cookware doesn’t react with acidic foods.

Cons of stainless steel cookware.  There are a few potential concerns of stainless steel cookware.  One concern some people have is that many stainless steel pots include an aluminum core.  However, this is not the same as cooking in aluminum pots and pans, as in stainless steel cookware with an aluminum core, the aluminum is sandwiched  in between layers of stainless steel.  As far as I know there is no evidence of the aluminum leaching out.  Speaking of metals leaching out, some people are concerned about stainless steel leaching nickel, which can be a concern if someone has a nickel allergy.  One study I came across showed that stainless steel cookware can be an overlooked source of nickel (and chromium), where the contribution is dependent on stainless steel grade, cooking time, and cookware usage (1).

This is why you want to purchase good quality stainless steel cookware.  Regarding the grade of stainless steel, this relates to the quality, durability, and temperature resistance.  Grades are divided into 200 series, 300 series, and 400 series.  The 300 series represent a high quality grade.  You’ll also see numbers such as “18/8” and “18/10”, and this represents the percentage of chromium and nickel.  Many of the good quality stainless steel cookware has an 18/10 interior.

CERAMIC

Although we have a stainless steel cookware set, we also have a ceramic saucepan!  Truth to be told, while I’m happy with stainless steel, if I were looking to purchase new cookware I would strongly consider ceramic.

Pros of ceramic cookware.  Some consider ceramic to be the safest type of cookware, as you don’t have to worry about leaching.  It is also very easy to clean, and it doesn’t scratch.  In addition, ceramic cookware is safe to use in the oven, on the stove top, in the microwave, and in the dishwasher.

Cons of ceramic cookware.  One of the big downsides is that ceramic cookware is more fragile than stainless steel or cast iron.  That being said, the quality of ceramic is better these days than in the past.  Another downside of using ceramic is that it takes longer to heat up.

CAST IRON

Pros of cast iron cookware.  Cast iron is another good choice, although there are some healthcare professionals who would disagree.  There is no question that cast iron is durable.  Another benefit of cast iron is that it provides great conductivity.  I can’t say I have experience cooking with cast iron pots and pans, but from what I have read, as long as you season the cookware well the food is unlikely to stick.  Of course if anyone has any experience using cast iron cookware I’d love to hear from you in the comments below!

Cons of cast iron cookware.  Probably the main controversy with using cast iron is that the iron can leach into the food you’re cooking.  Some think getting iron in this manner can be a health benefit, and if someone has an iron deficiency it can be, although I think it’s safe to say that you should try to get your iron through food whenever possible.  That being said, the small amount of iron shouldn’t be a problem with most people, although it can be problematic if someone has an iron overload issue.  Cast iron cookware is also extremely heavy, and it can rust if not properly maintained.

GLASS

Pros of glass cookware.  Glass cookware doesn’t seem to be very popular, although glass is very safe for cooking, as you don’t have to worry about leaching anything into food.  You can put glass cookware in the microwave if you’d like.  Another advantage of glass cookware is that the food can be watched while covered.  We do have some glass pans that we use in our home.

Cons of glass cookware.  One disadvantage of glass cookware is that it is more fragile than stainless steel or cast iron.  The heat distribution also isn’t as good as with other types of cookware, and glass also can be more challenging to clean (I can tell you from personal experience!). 

Which Cookware Should You Avoid?

ALUMINUM COOKWARE

Aluminum pots and pans are very popular because they conduct heat well, and they are very cost effective.  Of course the big concern is aluminum leaching into the water or food when cooking.  Some will argue that the small amount of aluminum you get from cookware isn’t harmful, but since there is evidence of aluminum causing neurotoxicity (2) (3) it probably is best to do everything you can to reduce your exposure to this heavy metal.

Can Aluminum Affect Thyroid Health?

I couldn’t find any evidence that aluminum can directly affect thyroid health.  Interestingly, while doing research for this blog post I came across a journal article which showed that aluminum is in Synthroid, which many of my hypothyroid patients take, although apparently the maximum aluminum levels are well below the FDA-determined minimal risk level for chronic oral aluminum exposure (4).

Is there any evidence that aluminum can trigger an autoimmune condition such as Graves’ disease or Hashimoto’s?  This is controversial, as while there are no studies directly linking aluminum with thyroid autoimmunity, there is concern about aluminum adjuvants found in vaccines being a possible autoimmune trigger (5) (6).  Of course the focus of this blog post is on cookware, not vaccines, and while I would recommend to avoid using aluminum cookware, I don’t think using such cookware would cause a thyroid or autoimmune thyroid condition, although it might lead to other health conditions over a prolonged period of time.

NONSTICK COOKWARE

The main reason why many people use nonstick cookware is because it’s easier to clean.  But there is a big concern over the chemicals.  Teflon is the most well known, as it’s made with a chemical called polytetrafluoroethylene (PTFE).  This does a wonderful job of preventing food from sticking in pans when cooking, and the cookware is also easy to wash.  But even at normal cooking temperatures, PTFE-coated cookware releases various gases and chemicals that present mild to severe toxicity (7).

PFOA (Perfluorooctanoic Acid) is used in the synthesis of PTFE.  PFOA has been replaced with other chemicals such as GenX, but these alternatives are also suspected to have similar toxicity (7).  It’s the same old story, as one toxic chemical is replaced with another toxic chemical.  Bisphenol A (BPA) is a good example of this, as now you see BPA-free plastic bottles everywhere, but unfortunately these plastics have other equally toxic chemicals, which I discussed in a blog post entitled “Why BPA-Free Products Might Still Harm Your Thyroid Gland“.  So just because something is listed as “PTFE free” doesn’t mean it doesn’t have any harmful chemicals.

Can PTFE or PTOA Affect Thyroid Health?

A few journal articles show that perfluorooctanoic acid (PFOA) has thyroid and endocrine-disrupting properties (8) (9) (10).  The most recent article was a review that showed that an accumulation of PFOA was documented in thyroid cells, and a cytotoxic effect was observed after exposure to extremely high concentrations of these compounds (8).  While a single use of a teflon pot or pan probably doesn’t involve high concentrations of PFOA, I would be very cautious about using such cookware on a regular basis.

The Risks of Eating Out

While you can control what cookware you use while in your home, this of course isn’t the case when you eat out.  I’m not suggesting that you should never eat out, but while I’m sure many people reading this try to eat healthy even when eating out, many restaurants use aluminum pots and pans, and perhaps even nonstick cookware.  Once again, I realize that we live in a toxic world, and regardless of what you do you’ll be exposed to chemicals on a daily basis.  But this doesn’t mean that you should do everything you can to minimize your exposure to these chemicals.   Besides trying to eat at home as much as you can, if you have a favorite restaurant you go to on a regular basis you might want to find out what type of cookware they use.

What Cookware Do You Use?

Please let me know what cookware you use in the comments section below.  Most of my experience is with stainless steel cookware, and so I’d be especially interested in hearing your experience with other type of cookware.  Perhaps you have experience with a type of cookware I didn’t discuss in this blog post, such as stoneware?  Either way, please share your experience below.