The Many Hidden Dangers of Fluoride

This post is the last installment in my ten-part Minerals and Your Thyroid series published in 2015, where I’ve highlighted eight thyroid-supportive minerals (iodine is a two-parter) and one troublemaker: fluoride. The original title was ‘This is Your Thyroid on Fluoride,’ but I changed it to reflect the many concerns outlined here.

Fluoride symbol: F- (Fluoride is the negative ion of fluorine.)
Atomic number: 9

See, even the chemical symbol has a negative sign in it.

Fluoride gets a big F. And an F- at that.

Here’s the short story. Until the 1950s, fluoride was administered to those with hyperthyroidism to suppress thyroid function.

You could stop reading right here. But perhaps you’d like more information on where fluoride lurks and the other serious concerns around fluoride ingestion.

[Here are the other Minerals posts: CalciumCopperIron, Iodine (Part 1Part 2), MagnesiumManganeseSelenium, and Zinc. An iteration of these articles made their way into our #1 best-selling Essential Thyroid Cookbook: Over 100 Nourishing Recipes for Thriving with Hypothyroidism and Hashimoto’s and its Companion Guide.]

First, let’s discuss how fluoride is wildly unsupportive to your thyroid.

According to Dr. John Douillard, “Research in the 1950s showed that all that was needed to suppress the thyroid was 2 - 5 milligrams of fluoride per day for a couple of months. It’s now estimated that the average American gets somewhere between 1.6 to 6.6 milligrams of fluoride daily.”


Fluoride as a halogen

You may remember that I touched on halogens in this iodine post.

According to Amy Myers, MD, “Iodine is part of the halogen family, which also includes fluorine, chlorine, and bromine.”

Again, fluoride is the negative ion of fluorine. 

According to Mark Hyman, MD,“ Chlorine, fluoride, and bromide all compete with iodine during the production of thyroid hormones by the thyroid gland.”

Dr. Douillard says, “When iodine is low in the body, the other available halogens can uptake into and block the thyroid gland.

“Since fluoride has become a ubiquitous part of our food and environment, low iodine levels in the body in combination with excess environmental fluorides may cause fluoride to uptake into the thyroid. From there, it may compete with iodine and act as an effective thyroid suppressant, just like it did in the 1950s.”

Dr. Myers continues, “Fluorine, chlorine, and bromine are similar enough to iodine that your thyroid will suck them up and store them in place of iodine, effectively ‘displacing’ iodine.

“Of course, just because these chemicals look like iodine doesn’t mean they can be used to make thyroid hormones. If fluorine, chlorine, and bromine are displacing iodine, your ability to produce thyroid hormones is reduced, which can lead to low thyroid hormone levels and hypothyroidism. The higher the concentration of these chemicals and the lower your iodine levels, the more likely it is that your thyroid function will be negatively impacted.

“These three chemicals are now frequently added to our water, foods, and household products, and I believe this is one of the main reasons thyroid disease is now at an epidemic level.”

Know where to look

It’s important to know how and where you’re getting fluoride exposure. You’re likely absorbing more than you think.

Probably the most ubiquitously known source of fluoride is toothpaste and dental treatments. But it’s also in our municipal water supply (tap water).

According to Frank Lipman, MD, fluoride “is a poison being put into our drinking water,” a “disease-causing agent,” and an “evolving social experiment.”

I think the thing that disturbed me the most about a video that Dr. Lipman made a few years ago was the reference to using fluoridated water in making baby formula.

Dr. Joseph Mercola states, “There’s no doubt about it: fluoride should not be ingested. Even scientists from the EPA’s National Health and Environmental Effects Research Laboratory have classified fluoride as a ‘chemical having substantial evidence of developmental neurotoxicity.’”

See below for more on neonatal and childhood fluoride exposure and negative cognitive and neurodevelopmental effects in children.

According to Amy Myers, “A recent, large-scale study published earlier this year reported that rates of hypothyroidism in areas that added fluoride to their water system were twice as high compared to areas without added fluoride in their water.”

Did you know that most countries in the EU don’t add fluoride to their water? And there are more people drinking fluoridated water in the U.S. than the rest of the world…combined. Oy.

Countries that fluoridate their water >

Go here for the Environmental Working Group’s Tap Water Database > (enter your zip code)

Other sources of fluoride include: 

  • Some medications and supplements (This is probably not a conclusive list, but here are some of the biggies: chemotherapy, steroids, statins, psychiatric drugs (including anti-anxiety meds and antidepressants), antacids, antibiotics, antifungals, and arthritis meds.)
  • Some teas (mostly red and black)
  • Preservatives in food
  • Chewing tobacco (who does this?!)
  • Bottled drinks (most are made with tap water)
  • Canned food items (ditto above…many are floating in tap water)
  • Nonstick cookware
Your thyroid on nonstick

If you’re still using nonstick, the convenience of being able to slide your eggs out of the pan isn’t worth it.

According to Leah Zerbe, “PFOA is part of a group of problematic nonstick chemicals that fall into the perfluorinated compounds (PFCs) class, a family of fluoride-containing chemicals with unique properties that make products stick- and stain-resistant. 

“In a study published in the journal Epidemiology, scientists found that more than 10 percent of people exposed to drinking water contaminated with perfluorooctanoic acid (or PFOA, made by DOW Chemical) reported having some manifestation of a thyroid problem.

“Comparing blood levels and years of exposure with incidence of thyroid issues, the researchers were able to say that higher PFOA exposure was associated with thyroid dysfunction. The study looked at more than 30,000 people.”

Nonstick cookware, while probably the most prevalent source of nonstick chemicals, isn’t the only culprit. PFOAs are also in:

  • Dental floss
  • Raincoats
  • Pizza boxes and fast food containers
  • Microwave popcorn bags
  • Furniture and carpeting (treated with Scotchguard, Teflon, Stainmaster, etc.)
  • Paper plates
  • Household dust

If you’re still using nonstick, switch to cast iron, enamel, glass, or stainless steel. Quick-like. (I use mostly cast iron for the added benefit of iron leeching into my food.)

Fluoride and oral “health”

Most European countries don’t fluoridate their water. And guess what? Their oral health doesn’t suffer.

We’ve been bamboozled into believing that fluoride reduces the risk of cavities and that adding it to our water supply is “for the common good,” but according to Dr. Myers, “Fluorine, in the form of fluoride … was supposedly added to promote dental health, but recent research has shown that fluoride does not actually decrease the risk of cavities in adults at any significant level.”

In fact, there’s evidence that too much fluoride can harm tooth enamel.

Other possible risks of fluoride exposure: 

Highlight: save our children’s brains

According to this damning Children’s Health Defense article, a lawsuit against the U.S. Environmental Protection Agency (EPA) “seeks to end water fluoridation based on science linking low-level fluoride exposure to lower IQ scores in children. [A] NTP (National Toxicology Program) report found that neonatal and childhood fluoride exposure had negative cognitive and neurodevelopmental effects for children.”

Association Between Maternal Fluoride Exposure During Pregnancy and IQ Scores in Offspring >

Dr. Mercola continues, “Each 0.5 mg/L increase in fluoride over 0.8 mg/L in the mother’s urine was associated with a 2.5-point reduction in IQ and a 3.15-point reduction in general cognitive index scores in the child. As the level of fluoride increased, IQ decreased — across the full range of exposures — which means there’s no level at which there is no detrimental effect on cognition; it’s only a matter of degree.”

Highlight: infertility

Two things that have had my ire for many years:

  1. The lame and ignorant term, “unexplained infertility.” It’s never unexplained.
  2. Women get most of the blame (and shame) when a couple can’t conceive.

I could expatiate about the many reasons that doctors never broach with their (often despondent) patients about why they’re not getting pregnant. A big one? Fluoride exposure.

Fluoride’s effect on male reproductive system: human studies >

Fluoride exposure alters the ultra-structure of sperm >

Exposure to high fluoride concentrations in drinking water is associated with decreased birth rates >

Fluoride Fact on Human Health and Health Problems: A Review > (Scroll down to the heading, Fluoride Effect on Reproductive Health)

Here’s what you can do: 
  • Switch to fluoride-free toothpaste. You have to look specifically for brands that say, “fluoride-free” as many fluoride-containing brands won’t specify that they contain fluoride.
  • Find a holistic dentist who “gets it.” Here are some resources for holistic dentistry: 1, 23
  • Filter your water. (See heading below.)
  • Consider iodine supplementation. I know, I know. This is a controversial one…

Before going gangbusters with iodine, you may want to read my two iodine posts in this Minerals series (12). Iodine supplementation is far from cut and dried.

But according to Dr. Douillard, “In numerous studies, iodine supplementation has been found to significantly increase in the urinary detoxification of both fluoride and bromide, thus taking a significant toxic load off the thyroid. In one study, only one day after supplementing with 50 mg of iodine, urinary excretion of bromide increased by nearly 50% and fluoride excretions increased by 78%.”

What about filtering?

Fluoride is but one major concern about what’s in U.S. tap water (think: heavy metals and pharmaceuticals). So it’s critical to filter it. Please hear me when I say that that Brita isn’t going to cut it.

(Speaking of heavy metals, that’s a whole other…heavy topic. Metals are a major trigger for autoimmunity. Go here for the single best way to detox metals from your body.)

Fluoride is removed by:

- Reverse osmosis
- Distillation

I’ve used a few filters over many years, including a reverse osmosis filter, which I no longer have.

While an RO filter is considered one of the only ways to filter fluoride, it’s “dead water.”

In fact, up until two years ago, the FDA did not recommend RO water for drinking because RO filters strip those oh-so-important minerals from our bones and tissues. (Now the FDA considers RO water the best drinking water. Shakes head.)

Distillation also strips all minerals.

The risks of demineralized water >

Additionally, RO and distilled water are always acidic—in fact, municipal water districts are required to add lye so the treated water doesn’t corrode the pipes. Oy.

If this is the case, what on earth is it doing to our bodies?

Our blood pH must always be mildly alkaline and if we’re too acidic, our body, with all its innate intelligence, has to pull minerals from itself to bring pH back to an alkaline state, which is one of the mechanisms of homeostasis.

Yes, I know that many add a pinch of sea salt to their RO water, but it’s difficult to know if this gets the job done…many are mineral deficient, largely because of decreased soil quality over many decades, and that pinch isn’t likely to meet the needs for a full spectrum of minerals. Yes, diet is important (which is why I created this Minerals series in the first place), but we don’t want our water “dead.”

Coming soon: More about filtration and what I’m using for my water system, which I’ve recently updated.

It’s important to maintain balance with this. Although I’ve gone a little cross-eyed in researching fluoride and also water filtration, my goal isn’t to obsess, but to filter as many toxins as possible while retaining mineral content to preserve the integrity of my bones and tissues. Again, more very soon on what I’m doing.

Thank you for being a part of this Minerals and Your Thyroid series. I hope that you benefitted from it as much as I enjoyed researching and writing it.


Hi Jill,
thank you for your newsletters!  It's all great info.

I have only a small remark to this one about fluoride. I completely agree on not using the non-stick cookware. And I don't know much about cast iron. Just want to say that iron leaking from a pan is inorganic and will not be utilised by the body for good. All inorganic iron is stored in cells just like scrap metal in a factory. It only gets on the way. Once during a lecture about iron, I have seen pics taken under a microscope. I was very impressed with what I saw and since then never take any supplements containing iron. Just smth to keep in mind. 

Thank you so much for all this information you have made so freely available. Your dedication and commitment are much appreciated.

Thank you so much for this brilliant series that summarises so well and succinctly how these nutrients affect and interact with the thyroid.  I wonder about the use of Ceramic coated non-stick pans, the ones that are free of all PFOAs and PFCs.  I have one and it actually works a lot better than the Teflon coated pans did.  

I am very much looking forward to your cookbook - if it is as down to earth as these articles have been it will be very useful.

the iodine intake is the most contradicting and confusing. many theories promote iodine and some don't. but, the confusion comes with the food intake. foods containing iodine are on the list of those "good foods" from those who discourage iodine intake with hypothyroidism. and example is garlic. many contradicting theories regarding treating the cause vs. treatment of symptoms. as I have several auto-immune issues its difficult to to determine if my auto-immune disorders created my hypothyroidism or my hypothyroidism crated my immune disorders. which one should be treated and how. thank you for sharing.

Regarding chlorine, it was use as a water sanitizer during the Korean War. Soldiers were issued chlorine tablets to.kill bacteria in unsafe water sources . By accident soldiers who were killed in action, in their twenties had autopsies performed. Strangely, most had severe cases of atherosclerosis.  Further research shows a direct atherosclerosis and consumption of chlorinated water.

Thank you for the very informative update concerning fluoride. Can you comment about fluoride and/or chlorine in swimming pools? I have been diagnosed as having  hypothyroidism many years ago. I enjoy swimming and only have access to a chlorinated swimming pool. I am most appreciative to all the information you share. Thank you.

Hi Cynthia, yes, I recently learned that they add fluoride to some pools "to prevent tooth decay." Just insane. 

Chlorine is a big enough problem. In addition to it being hard on the thyroid (it displaces iodine), it can cause or exacerbate yeast/candida. 

For a few years, I've gone out of my way to find salt water pools for my daughter and me. If we’re going to swim in a chlorinated pool, I increase our Vitamin C intake and rub a small amount of nascent iodine on our necks, around the thyroid area. When she was little, I put straight up coconut oil on her because it actually acts as a barrier, despite some thinking that it absorbs into the skin…it really doesn’t. 

Thank you for the indepth information! Can you please share the water filtration system you're currently using?  

Hi Kate, I've done such a deep dive into this, I now know that one size definitely doesn't fit all. It depends on your water source (municipal? well?) and your water report, which I can run for you. I do prefiltration and ionization. Email my assistant at and we’ll share some more info.

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