Your thyroid and fluoride 

According to Margie King (graduate of the Institute for Integrative Nutrition) latest research shows drinking fluoridated water greatly increases your risk of developing an underactive thyroid or hypothyroidism.

Hypothyroidism or low thyroid function causes fatigue, weight gain, constipation, aches, dry skin, thinning hair, and intolerance to cold. It can also cause slowed heart rate, depression, and impaired memory.

According to Dr Mark Hyman ‘Chlorine, fluoride and bromide (collectively called halogens) all compete with iodine during production of thyroid hormones by the thyroid gland. When iodine is low in the body the other available halogens can uptake into and block the thyroid gland. From there, it can compete with iodine and act as an effective thyroid suppressant.

Dr Amy Myers says that these halogens are so similar to iodine that your thyroid will suck them up and store them in place of iodine, effectively ‘displacing’ iodine.Even though these chemicals(halogens) look like iodine, they cannot be used instead of it. If these halogens are displacing iodine, your ability to produce thyroid hormones is reduced, which can lead to low thyroid hormone levels and hypothyroidism.

A study from the UK finds that fluoride added to drinking water is associated with a 30% higher rate of diagnosed hypothyroidism.[i] Actual rates of under-active thyroid may be much higher since this study was limited to people who were diagnosed. Many more may suffer with an impaired thyroid and not receive necessary treatment. In the study researchers looked at the 2012 levels of fluoride in the drinking water supply in the UK. About 10% of the English population or six million people live in areas with naturally or artificially fluoridated water containing 1 milligram of fluoride per litre of drinking water. They found that in areas with fluoride levels above 0.3 mg of fluoride per litre of water, rates of hypothyroidism were 30% higher. The researchers also compared two communities, one with fluoridated water and one without. They found that the fluoridated area was twice as likely to report higher rates of hypothyroidism.

Why is fluoride in your water?

Fluoride became popular with dentists and public health authorities just before World War II thanks to bad science. H. Trendley Dean was a dentist then working for the U.S. Public Health Service. He conducted a study of tooth decay in 345 communities in Texas. And he found that communities with about 1 part-per-million (ppm) of fluoride in their water supply had fewer cavities. Dr. Dean declared this the optimal level of fluoride for dental health and he advised adding fluoride to the public drinking water. It wasn't until years later that scientists reviewing Dean's Texas study found out how flawed it was. Dr. Dean had selectively used findings from 21 cities to support his conclusions. He ignored data from 272 communities that did not support his results.

Since Dean's first study, there have been no double-blind studies proving that fluoride in the water reduces cavities. The World Health Organization (WHO) found no difference in tooth decay between countries that fluoridate their water and those that do not. In fact, the science shows that fluoride increases cavities. The largest study of 400,000 students revealed that each 1 part-per million (ppm) of added fluoride in drinking water increased tooth decay by 27%.

[ii] The National Institute of Dental Research conducted another review of 39,000 U.S. school aged children and found that each 1 ppm of fluoride in the water supply increased tooth decay by 5.4%.[iii] Besides making cavities worse, fluoride permanently stains teeth. In 25% of children it causes dental fluorosis – brown or yellow teeth mottled with white spots. Dental fluorosis can be an indication that the rest of your body, such as the brain and internal organs, has been overexposed to fluoride as well.

In addition to hypothyroidism, studies prove other serious health dangers of fluoride:

  • Heart Disease: Fluoride is linked to higher cardiovascular disease risk. A study of 61 patients found a strong link between fluoride and calcification of the arteries (atherosclerosis), as well as increased cardiovascular events.[iv]
  • Brain Damage and Low IQs: More than 100 published studies document fluoride's damage to the brain. Researchers from Harvard University's School of Public Health found that children in high-fluoride areas had significantly lower IQ scores than those who lived in low-fluoride areas. They warned of the adverse effect of high fluoride exposure on children's neurodevelopment.[v]
  • Cancer: Studies from Dr. Dean Burk, former head of the Cytochemistry Section at the National Cancer Institute, estimate that fluoridation caused 10,000 excess cancer deaths. His conclusions were based on a study of rats that drank fluoridated water and showed an increase in tumours and cancers in oral squamous cells and thyroid cells, and rare forms of bone and liver cancer.[vi]
  • Weakens Bones: As fluoride builds up in bones, it can lead to skeletal fluorosis. That's a debilitating condition making bones extremely weak and brittle. Epidemiological studies show high fluoride exposure increases the risk of bone fractures, especially in the elderly and diabetics. Drinking fluoridated water over many years may increase the rate of bone fractures. It disrupts enzymes and prevents them from producing collagen, the structural protein you need to build strong flexible bones. One study found female skeletons with the highest fluoride content had the most severe osteoporosis.[vii]
  • Increases ADHD: A recent six-year study published in the journal Environmental Health, found that U.S. states with a higher proportion of fluoridated water had a higher prevalence of Attention Deficit Hyperactivity Disorder, or ADHD. Each 1% increase in artificial fluoridation was associated with approximately 67,000 to 131,000 additional ADHD diagnoses.[viii]

Fluoride has never been proven to be safe.

  • In fact, the US Agency for Toxic Substances and Disease Registry lists fluorides among the top 20 substances posing the most significant threat to human health. Yet it is still in the U.S. water supply. [ix]

What can you do to reduce your exposure to toxic fluoride?

  • Stop Buying Fluoride Toothpaste.
  • Filter Your Water.
  • I use an under the sink fluoride and chlorine filter that I buy from Water Technology in Cork.
  • I use an Ava shower filter that filters Fluoride and Chlorine. I got that through
  • Reverse Osmosis Filter
  • Buy Organic Produce –
  • Produce grown with fluoride-based pesticides can have extremely high levels of fluoride. Other foods that have high fluoride levels include citrus fruits, potatoes, grapes and raisins. Buy only organic versions of these foods to minimize your exposure.
  • Avoid non-stick pans [x]
  • Read Labels-it can be found in some medications and supplements, as preservatives in food and in some teas (mostly red and black).

[i] S Peckham, D Lowery, S Spencer. "Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? A large observational study of GP practice data and fluoride levels in drinking water." Journal of Epidemiology & Community Health, February 2015 DOI: 10.1136/jech-2014-204971

[ii] Teotia SPS, Teotia M "Dental Caries: A Disorder of High Fluoride And Low Dietary Calcium Interactions (30 years of Personal Research)" Fluoride, 1994 27:59-66 (1994)

[iii] Yiamouyannis, J "Water fluoridation and tooth decay: Results from the 1986-1987 national survey of U.S. school children" Fluoride 23:55-67 (1990).

[iv] Yuxin Li, et al, "Association of vascular fluoride uptake with vascular calcification and coronary artery disease." Nucl Med Commun. 2012 Jan;33(1):14-20. PMID: 21946616

[v]Anna L. Choi, et al, "Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis." Environ Health Perspect 120:1362–1368 (2012)

[vi]Lita Lee, Ph.D. 03/07/2005 Fluoride A Modern Toxic Waste

[vii] Alhava EM, Olkkonen H, Kauranen P, Kari T. "The effect of drinking water fluoridation on the fluoride content, strength and mineral density of human bone." Acta Orthop Scand. 1980:51: 413-420. [ Abstract ]

[viii] Ashley J Malin and Christine Till "Exposure to fluoridated water and attention deficit hyperactivity disorder prevalence among children and adolescents in the United States: an ecological association." Environmental Health 2015, 14:17 doi:10.1186/s12940-015-0003-1


[x] Full CA, Parkins FM. (1975). Effect of cooking vessel composition on fluoride. Journal of Dental research 54: 192.


* indicates required

Thyroid Nutrition Ireland: We will use the information you provide on this form to be in touch with you and to provide updates and marketing. Please let us know all the ways you would like to hear from us:

You can change your mind at any time by clicking the unsubscribe link in the footer of any email you receive from us, or by contacting us at We will treat your information with respect. For more information about our privacy practices please visit our website. By clicking below, you agree that we may process your information in accordance with these terms.