Fluoride and the Thyroid

The UK government are making plans to add fluoride to all tap water in the UK in a bid to reduce tooth decay. Fluoride has already been controversially added to tap water in certain parts of the country (mainly the Midlands, Yorkshire, North East and North West of England), and even though the chief medical officers for England, Wales, Scotland and Northern Ireland have dismissed further safety concerns it looks like they may not have properly considered, (or worse forgotten), the 15% of people in the UK living with a thyroid condition. They may also have failed to acknowledge that perhaps the reason for tooth decay in the first place isn’t the potential lack of fluoride, but the abundance of refined sugar found in processed foods, soft drinks and even some foods labelled as ‘healthy’, as well as sub-optimal dental hygiene which can contribute to reduced tooth enamel.

In trace amounts fluoride is beneficial for the body as it helps keep teeth and bones healthy, but excessive consumption through a combination of drinking fluoridated tap water, using dental products like fluoride toothpastes, as well as consumed naturally through food and drink can actually cause dental fluorosis (mottling of the teeth), skeletal fluorosis (pain and stiffness in the joints) and wreak havoc on the thyroid gland which is very sensitive to fluoride. A study in 2015 exposed rats to 20ppm sodium fluoride per day for 30 days and found that it caused thyroid dysfunction by supressing normal functioning of the thyroid gland and the production of thyroid hormones.

Fluoride versus Iodine:

The thyroid needs iodine to make thyroid hormones like T4 and T3. Iodine is transported into the thyroid gland via receptors, but fluoride, which structurally looks very similar to iodine and therefore has an affinity for the thyroid gland too, can block iodine from getting through which decreases the amount of T4 and T3 it can produce thereby disrupting its function. Fluoride in this regard acts a bit like a road block for iodine. No matter what route iodine takes the road blocks prevent it from reaching its destination.

So, even though fluoride is necessary for healthy teeth and bones it’s important to avoid exposure beyond limits that are safe as this can have a detrimental effect on the thyroid. It’s equally important to drink plenty of water and stay hydrated throughout the day to help flush toxins and pathogens from your body, but drinking water laden with fluoride (especially if you have a thyroid disorder) may potentially have a negative impact on your body and contribute to symptoms including brain fog, fatigue, low mood and poor memory.

What can I do?

Luckily there are some alternative ways you can protect your health. Firstly, there are lots of high-quality drinking water filtration systems that can purify tap water and remove up to 99.9% of harmful chemicals including fluoride and chlorine as well as other harmful bacteria, viruses and heavy metals. My personal favourite is the Berkey – They are a big outlay, but replacing the filters around every 10 years rather than every month (which can add up), makes them more cost-effective overtime. Plus, you do your bit for the environment and reduce the number of filters ending up in landfill each year. Another approach is to install a filter on your shower head which reduces the absorption and inhalation of toxins and chemicals which can have a significant impact on your health. This is a really simple fix which you can do yourself, so no plumber required, and the filters need changing on average around every 6 months. You can find out more by visiting either or Other easy solutions are bottling up your filtered water and taking it with you when you leave the house or ordering bottled water instead of tap water when eating at a restaurant.

If you want to find out more, your local water supplier should also be able to tell you if they have adopted a water fluoridation scheme, and if so, how much fluoride is in your water. Alternatively, some companies allow you to find this information out online by entering your postcode.

It’s important to have as much information as possible so you can make an informed choice about how to look after your body, and simple changes like the ones mentioned above can be really beneficial for your health. If you have found the information in this article useful and would like to talk to me about how I can help you improve the health of your thyroid through realistic and achievable nutritional support please get in touch and book in for a free 20-minute discovery call. This is a time for me to explain to you what I offer and for you to ask any questions regarding my programmes and consultation process. You can book in by sending a message to 


Dey, S., and Giri, B. (2015) ‘Fluoride Fact on Human Health and Health Problems: A Review’ Medical Clinical Reviews. 2(1) Available at: