Systematic review finds excess fluoride interferes with thyroid function.
Excess fluoride from fluorinated drinking water has been linked to hypothyroidism in a recent systematic review (a high-quality summary of many studies). The review also found that the fluoride had other health effects like dental and skeletal fluorosis. Fluoride may disrupt the thyroid by inhibiting the ability of iodine to function in the body. Other sources of fluoride include processed beverages and foods, Teflon pans, and pesticides. Best steps to take: filter your water and focus on healthy nutrients. See the video for more details.
Dr. Michael Ruscio, DC: Hi, this is Dr. Ruscio, and let’s discuss the question, “Can fluoridated water or non-filtered water contribute to hypothyroidism?” The short answer here according to the best available data, which is a systematic review, is yes, it does appear that fluoridated water can contribute to hypothyroidism.
Let’s outline the details so you have all the necessary information.
Dr. R’s Fast Facts Summary
Can fluoride in water cause hypothyroidism?
Study: A systematic analysis on the possibility of water fluoridation causing hypothyroidism 
- Study results
- Out of the 37 articles related to the association of fluoride and hypothyroidism, 10 articles met the inclusion criteria
- The analysis suggested a positive correlation of excess fluoride and hypothyroidism
- Interesting notes from this study
- “there is sufficient evidence of the ill effects of excessive fluoride content in water, causing skeletal and dental fluorosis”
- “Reviews also indicated that fluoride is an endocrine disruptor of tissues competitively requiring iodine.”
- See my previous review, also finding an association to fluoride and hypothyroid
Why might fluoride be problematic for thyroid health?
- It would appear fluoride is competitively inhibiting the ability of iodine to function in the body
- Listen to this podcast episode for more on halogens
What you can do?
- Filter your water
- Ensure you are getting adequate iodine intake:
- Recommended Dietary Intake: 150 micrograms
- Ideal might be 450 micrograms per day
- Too much or too little iodine can both be a problem
Download this Episode (right click link and ‘Save As’)
The Possibility of Water Fluoridation Causing Hypothyroidism
Allow me to put the abstract on the screen, a systematic analysis on the possibility of water fluoridation causing hypothyroidism. Now, a systematic analysis is a review of the available data, so it’s very powerful data. It’s not just one study, but rather, an analysis and summary of all the available literature. So this is very powerful information and is arguably the highest level of scientific evidence.
At least, it’s the best available evidence to answer this question to-date. Let’s quote the findings from this research group.
“The present systematic review suggests a positive correlation between excess fluoride and hypothyroidism. This calls a need for further well-controlled studies in this otherwise emerging, alarming issue.”
We’ll outline this further. Let’s look at what data was analyzed. To quote:
“37 full articles were related to the association of fluoride and hypothyroidism. Of the 37 articles, 10 articles met the inclusion criteria.”
Meaning only the 10 articles that were well-performed, seem to have a reduced or minimal risk of bias, and were high-quality. So we look at all the data 37, and pair down to only the highest quality of those 37, 10, and this is what is analyzed. We’re really kind of cutting the fat, looking at the best quality data. Continuing here to quote:
Can fluoride in water cause hypothyroidism? The short answer …. Yes. You’ll find out why in this video and what the research is showing. Click To Tweet
“The analysis suggests a positive correlation of excess fluoride and hypothyroidism.”
Okay. An interesting note here:
“There is sufficient evidence of the ill effects of excess fluoride content in water, causing skeletal and dental fluorosis. Reviews also indicate that fluoride is an endocrine disruptor of tissues competitively requiring iodine.”
We’ll come back to what that competitive requirement means here in just a second. It tells us part of the mechanism through which too much fluoride in your system can actually interfere with iodine. Which is what’s ultimately one part of what’s needed for a healthy thyroid function.
The Connection Between Fluoride and Iodine
Before we move to the connection between fluoride and iodine, I’ll provide some references to other evidence points I’ve reviewed on this. So if you want to read more or listen more on this issue, you have additional references at your disposal. Now, why might fluoride be problematic for thyroid health? Well, I don’t mean to torture you here with this periodic table of elements, but this is helpful in depicting how it is that fluoride and potentially even chlorine and bromine, can interfere with thyroid health by competitively inhibiting the ability of iodine to function in the body. I’ll put up on the screen a periodic table of elements and I’ll draw your attention to the lower right-hand corner where you see I or iodine.
Now, this is known as a halogen. One of the elements or a number of elements are classified as halogens. That’s what you’re seeing highlighted by the green row. You see above iodine is bromine, above that chlorine, and above that fluoride or fluorine. The theory, and there does seem to be some evidence to support this, is that these other halogens, in this case, namely fluoride, can outcompete for iodine receptors. So you have this iodine receptor, let’s say in the thyroid gland, and both iodine and fluoride can bind to it. Fluoride seems to be better at getting into that receptor than iodine. So if your fluoride levels are too high, they dislodge iodine, and you can almost end up with a pseudo iodine insufficiency. This is one of the main theories through which we think that fluoride, when too high, can cause problems with thyroid function. Again, if you’d like to explore the halogens further and the relationship between those, I’ll refer to a prior podcast where we went into quite a bit of detail on that topic.
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Reduce Your Exposure To Fluoride Via Water Filtration
What can you do? Well, fortunately, the solution here seems to be fairly simple; you can filter your water. You can fairly easily find out what water filters will filter fluoride or fluorine through a quick internet search. Most will, so just do a bit of research. It should not be too hard to figure that out. You can also ensure that you’re getting adequate iodine in your diet, which in the U.S., most people are.
The recommended dietary intake is 150 micrograms per day. Some evidence suggests that in patients at risk of thyroid disease, either hypothyroidism or hyperthyroidism, the sweet spot may be around 450 micrograms per day. Iodine is interesting in the sense that too much or too little, both pose a problem. So one of the things that we don’t want to do is look at this information about fluoride, understanding that iodine and fluoride kind of compete, think that you’ve been exposed to too much fluoride, and go on a campaign of using copious amounts of iodine in your diet. That also may be a problem.
The most practical path forward seems to be to reduce your exposure to fluoride via water filtration. You also may want to quickly Google a list of the other top sources where people are exposed to fluoride, one of which is fluoridated toothpaste, and reduce your exposure to those in addition to making sure you have adequate iodine in your diet. That should be sufficient.
Some recommend using high-dose iodine to try to do this kind of fluorine or fluoride flush. I don’t know if we really need to go to that extreme. It seems much more practical to adhere to the practice that seems to be the foundation in toxin reduction. Which is avoid exposure and focus on healthy nutrients in the diet. That seems to be the best long-term strategy.
In close, according to the best available evidence, it does appear there is a relationship between fluoridated water and hypothyroidism. Now, I wish we had a little bit better data in terms of, “Is this a 3% increase or a 50% increase?” because there does seem to be this tendency for people to overreact. I do not want to contribute to that overreaction at all, so I would not fret over this. I would not worry. I would simply look at this as a simple lifestyle practice you can employ. Filtering your water and avoiding other top sources of fluoride in a reasonable fashion is a proactive measure to improve the likelihood that you will not have any thyroid conditions in the future or any exacerbation of a current thyroid condition.
Further evidence may also disprove this, but it does seem, according to the best available data, looking at all 37 available studies and consolidating down to the 10 best, the relationship there did hold. A simple practice you can use to improve your thyroid health would be avoidance of fluoride. The best way to hit that end point would be to filter your water. I hope this information helps you get healthy and get back to your life.
What do you think? I would like to hear your thoughts or experience with this.
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