 Hi, this is Dr. Ruchio and let's discuss the question of can fluoridated water or non-filtered water contribute to hypothyroidism? The short answer here is the best available data, which is a systematic review, is finding that yes, it does appear that fluoridated water can contribute to hypothyroidism, but let's outline the details so you have all the necessary information. Let me put up here on the screen the abstract, a systematic analysis on possibility of water fluoridation causing hypothyroidism. Now a systematic analysis as we'll cover here in a second is a review of the available data. So it's very powerful data, it's not just one study, but rather a analysis and summary of all the available literature. So this is very powerful information and this is arguably the highest level of scientific evidence, at least it's the best available evidence to answer this question to date. And let's quote the findings from this research group. The present systematic review suggests a positive correlation between excess fluoride and hypothyroidism. This calls in 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 10 articles 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 pare down to only the highest quality of those 37, 10 and this is what is analyzed. So we're really kind of cutting the fat, looking at the best quality data and continuing here to quote. The analysis suggests a positive correlation of excess fluoride and hypothyroidism. So 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 and we'll come back to what that competitive requirement means here in just a second because 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 needed or one part of what's needed for healthy thyroid function. And just in brief here before we move to the connection between fluoride and iodine, I'll provide some references to other evidence points I've reviewed on this here just 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, and 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 via competitively inhibiting the ability of iodine to function in the body. Now I'll put up here on the screen a periodic table of elements and I'll draw your attention to the lower right hand corner where you see eye 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 here by the green row and 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 out compete for iodine receptors with iodine. So you have this iodine receptor, let's say in the thyroid gland and both iodine and fluoride can bind to it, but fluoride seems to be better at getting into that receptor than iodine. Now if your fluoride levels are too high they dislodge iodine and you can almost end up with this pseudo iodine insufficiency and this is one of the main theories through which we think that fluoride when too high can cause problems with thyroid function. And again if you'd like to explore further the halogens and the relationship between those I'll refer to a prior podcast where we went into quite a bit of detail on that topic. So what can you do? Well fortunately the solution here seems to be fairly simple. You can filter your water and you can fairly easily find out what water filters through a quick internet search will filter fluoride or fluorine most will. So just do a bit of research 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 US most people are. The recommended dietary intake is 150 micrograms per day and some evidence suggests that in patients with thyroid at risk of thyroid disease either hypothyroidism or hyperthyroidism the sweet spot may be around 450 micrograms per day. Fluorine 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. So if you think you've been exposed to too much fluoride you may go on this campaign of using copious amounts of iodine in your diet and that also may be a problem. So the most practical path forward seems to be reduce your exposure to fluoride via water filtration. You also may just want to quickly Google and I'll put up here on the screen 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 and 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 and it seems much more practical to kind of adhere to the practice that seems to be the foundation in toxin reduction which is avoid exposure and also focus on health and nutrients in the diet and that seems to be the best long term strategy. So in close according to the best available evidence it does appear there's a relationship between fluoridated water and hypothyroidism. Now I wish we had a little bit better data in terms of is this a three percent increase or a fifty percent increase because there does seem to be this tendency for people to overreact and 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 as a proactive measure to improve the likelihood that you will not have any thyroid conditions in the future or any exacerbation of the current thyroid condition. Now further evidence may also disprove this but it does seem again according to the best available data in this case when looking at all thirty seven available studies consolidating down to the ten best the relationship there did hold. So a simple practice you can use to improve your thyroid health would be avoidance of fluoride the best way to hit that endpoint would be to filter your water and I hope this information helps you get healthy and get back to your life.