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  • Writer's pictureAnita Hollerer-Squire

Is fluoride in drinking water safe?

Updated: Jun 14, 2021

Fluoride is found naturally in soil, water, and foods. It is also produced synthetically for use in drinking water, toothpaste, mouthwashes and other chemical products.

In the USA, UK, Australia, NZ and a few other countries the water authorities add fluoride to the municipal water supply, because some studies have shown that adding it in areas where fluoride levels in the water are low can reduce the prevalence of tooth decay.

The following graph shows the average decayed, missing or filled teeth at age 12 from 1975 to 2014.

Most European countries, Canada, Japan and Mexico don't use fluoride in their drinking water - and they have also seen a drop in tooth decay over the years - as the below graph shows.

Concerns have arisen regarding fluoride's effect on health, including problems with bones, teeth, thyroid dysfunction and lowering of IQ in children. Causing more worries is preliminary research in laboratory animals suggesting that high levels of fluoride may be toxic to brain and nerve cells.

In June 2015, the Cochrane Collaboration—a global independent network of researchers and health care professionals known for rigorous scientific reviews of public health policies—published an analysis of 20 key studies on water fluoridation. They found that while water fluoridation is effective at reducing tooth decay among children, no studies that aimed to determine the effectiveness of water fluoridation for preventing caries [cavities] in adults met the review’s inclusion criteria.

The Cochrane report also concluded that early scientific investigations on water fluoridation (most were conducted before 1975) were deeply flawed. “We had concerns about the methods used, or the reporting of the results, in … 97 percent of the studies,” the authors noted. One problem: The early studies didn’t take into account the subsequent widespread use of fluoride-containing toothpastes and other dental fluoride supplements, which also prevent cavities.

A study assessing the Intelligence Quotient (IQ) of 219 school children in India with different fluoride levels found that school children residing in areas with higher than normal water fluoride level demonstrated more impaired development of intelligence when compared to school children residing in areas with normal and low water fluoride levels. Concentration of Fluoride in the ingested water was significantly associated with the IQ of children.


Fluoride has beneficial effects on dental development and protects children's teeth against cavities.

My question: Do we need to add fluoride to drinking water so it gets into the bloodstream and potentially into the brain where it can cause a drop in kids IQ? Especially since other countries seem to manage tooth decay without adding it?

Let me know your thoughts on this!


Ministry of Health NZ:$file/Fluoride%20Neurotoxicity.pdf

US National Library of Medicine: Study of the effect of Fluoride Concentration in Drinking Water on Intelligence Quotient://

NFIS: 2014 water fluoridation review

Medical News Today:

Harvard Public Health:

Cochrane report:

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