Myth or Fact: Is Fluoride Toxic to the Brain?

For years, fluoride has been touted as a risk-free, effective way of preventing tooth decay. Its daily use had been supported by the American Dental Association, World Health Organization, and Center for Disease Control. It is thought to prevent tooth decay by depositing onto teeth during a process called remineralization, a natural process whereby minerals are deposited back onto areas of teeth that have been demineralized (areas of mineral break down). By depositing onto teeth, fluoride is thought to enhance the remineralization process by speeding it up and attracting other minerals, like calcium, to help strengthen teeth. Moreover, fluoride has been shown to inhibit cariogenic (cavity-causing) bacteria.


The History of Fluoride...

Since the 1940s, the addition of fluoride to the drinking water supplies (termed, ‘fluoridation’) became widespread in the United States. This was reported to have drastically lowered the rates of tooth decay. However, over the past decade, fluoridation has come under scrutiny, as evidence emerged that the declining rates of tooth decay may not be related to widespread fluoridated water supply. For example, the World Health Organization (WHO) published data on tooth decay trends internationally, and found that tooth decay rates have ‘precipitously declined’ in all western countries regardless of whether or not the country fluoridated the water. Moreover, in countries that have abolished fluoridated drinking water, the rates of tooth decay have not increased. This led to the conclusion that topical application of fluoride, rather than ingesting it (i.e., in the form of drinking water), contributes to tooth decay prevention.


Criticism of Fluoride...

In the recent years, fluoridated drinking water has come under ethical scrutiny, as many critics argued that US populations were receiving medical treatment without consent.  Additionally, the appropriate ‘dose’ of fluoride intake has been difficult to control due to the variation of fluoride levels in various water supplies, as well as its presence in a multitude of foods and products. Moreover, fluoride is not considered to be a nutrient to the human body, as there has never been a document case of ‘fluoride-deficiency.’


Health Concerns related to Fluoride...

What was more concerning was that evidence emerged that fluoride ingestion could be harmful. It was discovered that excess fluoride could lead to skeletal fluorosis - a health problem caused by excess accumulation of fluoride in bone, characterized by pain and tenderness of major joints as well as increased risk of bone fractures; dental fluorosis - tooth discoloration and pitting; and thyroid dysfunction - fluoride competitively binds to iodine and slows the production of thyroid hormones (Peckham and Awofeso, 2014). This can lead to hypothyroidism, a disorder in which the body produces too little thyroid hormone, which can lead to a multitude of symptoms, including weight gain, depression, fatigue, depression, and cognitive problems. Also, there is evidence that supports that chronic fluoride exposure is a possible cause of uterine and bladder cancer (Peckham and Awofeso, 2014).


Furthermore, there is unequivocal evidence to support that fluoride toxicity can harm the brain. Fluoride toxicity has been related to:

1. Decreased IQ and cognitive impairment in children

-A multitude of studies have been published on the harm that it can create within the developing brain of children. In 2012, Harvard published a meta-analysis of 27 different fluoride studies, and found that fluoride exposure was associated with reduced IQ in children.

-Moreover, in 26 of these studies, there was a relationship between high levels of fluoride and reduced IQ.

-A review published in the Lancet concluded that fluoride is a neurotoxin that damages the developing brain, thus increasing the risk of autism, developmental delay, ADHD, and learning disabilities.


2. Calcification of the pineal gland

-The pineal gland secretes a hormone called melatonin, which is important for regulating our sleep patterns

-Melatonin is also a potent antioxidant and neuroprotector.

-Calcification of the pineal gland leads to impaired melatonin secretion.

-Reduced melatonin can lead to insomnia.

-Reduced melatonin levels are also observed in various diseases, such as dementia, mood disorders, severe pain, cancer, and diabetes type 2 (Hardeland, 2012).


3. Poor memory and learning

-Fluoride has been shown to accumulate in the hippocampus (the structure in the brain involved in forming memories) and leads to impaired learning and memory formation in multiple animal studies (Jiang et al., 2014).

-Given its effects on the thyroid, thyroid dysfunction can lead to fatigue, depression, anxiety, brain fog / memory problems, and cognitive impairment.


How do I avoid fluoride toxicity?

In sum, while topical fluoride has been shown to help prevent dental cavities, excess exposure can lead to harmful health consequences.  How do you minimize your risk of fluoride toxicity? The best way is to limit your exposure to it. It is important to be aware of the commonly used products that contain fluoride, to carefully weigh the risks and benefits of fluoride use, and to make well-informed decisions about the products you use. Fluoride can be found in:

- Most US tap water supplies

- Foods such as tea, fruits, meats, and fish which may be exposed to fluoride.

- Common products such as non-stick cookware, toothpaste, mouthwash, and dental gel.

For tips on how to minimize fluoride exposure, refer to my article Four Tips to Minimize Fluoride Exposure.



Bhatnagar M1, Rao P, Sushma J, Bhatnagar R. Neurotoxicity of fluoride: neurodegeneration in hippocampus of female mice. Indian J Exp Biol. 2002 May;40(5):546-54.

European Commission. Critical review of any new evidence on the hazard profile, health effects, and human exposure to fluoride and the fluoridating agents of drinking water. Scientific Committee on Health and Environmental Risks (SCHER), 2011.

Hardeland, R. (2012). Neurobiology, Pathophysiology, and Treatment of Melatonin Deficiency and Dysfunction. The Scientific World Journal, 2012, 640389.

Jiang S, Su J, Yao S, Zhang Y, Cao F. Fluoride and Arsenic Exposure Impairs Learning and Memory and Decreases mGluR5 Expression in the Hippocampus and Cortex in Rats (2014) PLOS ONE 9(4): e96041.

Peckham, S., & Awofeso, N. (2014). Water Fluoridation: A Critical Review of the Physiological Effects of Ingested Fluoride as a Public Health Intervention. The Scientific World Journal, 2014, 293019.


Neuroscience HealthAnna Moise