Image of a running water faucet.

Fluoridation of Tap Water: Tooth Protection or Poison?

Lynn Adams
May 2, 2016

I recently saw a post on my Facebook feed that stated the fluoridation of tap water in the U.S. is causing neurological damage to children. As this conclusion was purportedly reached in a paper published in the “world’s most prestigious medical journal,” I was naturally intrigued.

The claim: “…a report from the world’s oldest and most prestigious medical journal, The Lancet, has officially classified fluoride as a neurotoxin — in the same category as arsenic, lead and mercury.” Anti-fluoridation proponents are convinced that neurodevelopmental disabilities like attention-deficit hyperactivity disorder, dyslexia, and autism are caused by chemicals like fluoride. The Lancet paper states that these disabilities “are now affecting millions of children worldwide in what they call a ‘pandemic of developmental neurotoxicity’; which, depending on how you define pandemic, could be true.

However, the link to fluoride in the drinking water seemed like a stretch. So I went to the Lancet article and found a two-line paragraph that mentioned fluoride. The paper states: “A meta-analysis of 27 cross-sectional studies of children exposed to fluoride in drinking water, mainly from China, suggests an average IQ decrement of about seven points in children exposed to raised fluoride concentrations.” This statement left me with two questions: (1) Since the studies were done in China and Iran, how does this relate to the U.S.? (2) How do they define ‘raised’?

In reading the paper, I realized that there are many reasons why the analysis, and the conclusion drawn from it, is flawed. For example: The authors only quoted one source – a meta-analysis by Choi et al. In this paper a number of important factors were not available for the majority of the studies. Most significant was the lack of official reports of lead concentrations in the study villages – a major confounding factor as lead exposure can lead to the same neurodevelopmental disabilities this paper is associating with fluoride exposure. The paper states, “Although most reports were fairly brief and complete information on covariates was not available, the results tended to support the potential for fluoride-mediated developmental neurotoxicity at relatively high levels of exposure in some studies.” This wording is wishy-washy at best, and makes no definitive statements regarding fluoride or its association with lower IQs.

So what do they mean by “high levels” anyway, and how does this compare to current drinking water standards in the U.S.? The exposed groups in these studies were drinking water with fluoride concentrations up to 11.5 mg/L (although we don’t really know the exact amount). These studies had a lot of variability, so the range was roughly 2 – 11.5 mg/L. The “low” fluoride groups were in the range of 0.5 – 1 mg/L range. This is, by the way, within the current recommended level for fluoride in drinking water in the U.S, which is 0.7–1.2 mg/L. So the studies done in China and Iran showed a potential for neurotoxicity at levels far above that which is found in U.S. drinking water, and the amount of fluoride the controls were exposed to correlates with the ‘safe’ levels maintained in U.S. drinking water. Which indicates to me that the fluoride levels in the U.S. would not negatively impact the IQs of children in this country.

An important point to make is that the policy in the U.S. isn’t just about adding fluoride to water; rather, it sets safe fluoride levels in drinking water that are optimized to protect public health. Most people don’t realize that there are communities across the U.S. that have natural levels of fluoride in their water at higher than recommended levels, and in that case, fluoride is actually removed. Unfortunately, this may not be the case in other countries where the addition of fluoride to drinking water is not regulated to the same degree.

In researching this topic further, I found a reliable source, the Institute for Science in Medicine, whose policy statement on fluoridation states, “The safety of CWF (community water fluoridation) has been comprehensively reviewed by numerous public-health authorities and scientific institutions. These include the US Public Health Service, World Health Organization, NCI, CDC, National Research Council, and National Health and Medical Research Council (Australia). None has ever identified any health risk with the levels of fluoride provided by CWF.”

Anyone who knows me will tell you I’m an advocate for the environment and public health. But in this case, I have to come down on the side of what sound science tells us – fluoride control programs in the U.S. protect public health as opposed to the alternative. I’m going to have to side with the Institute of Science and Medicine on this one (see policy statement in paragraph above).

Image courtesy of Dan Watson /

Lynn Adams

Lynn S. Adams, Ph.D. is an Alumni Fellow. She blogs about nutrition policy, the connections between nutrition and disease risk, the health effects of environmental exposures and the cancer prevention potential of natural products at Sci on the Fly. If you want Lynn to share her posts with you, follow her on Twitter: @lstedda68.


This blog does not necessarily reflect the views of AAAS, its Council, Board of Directors, officers, or members. AAAS is not responsible for the accuracy of this material. AAAS has made this material available as a public service, but this does not constitute endorsement by the association.

Comments (1)

nyscof (not verified)
May 11, 2016 at 8:16 am
The US National Toxicology Program (NTP) plans to review hundreds of studies linking fluoride to adverse brain effects. The report won’t be finalized until 2018 and may signal an end to the fluoridation program nation-wide 314 studies investigated fluoride’s effects on the brain and nervous system. This includes 181 animal studies, 112 human studies, and 21 cell studies, The majority of these studies were published after the 2006 National Research Council’s fluoride toxicology report concluded, "It is apparent that fluorides have the ability to interfere with the functions of the brain." Since proponents of fluoridation like to claim that fluoride only reduces IQ at enormously high doses, we draw attention to 23 studies where IQ reductions were found at levels at, or below, EPA's current ‘safe’ drinking water level (4 ppm) for fluoride, with a few studies even finding IQ loss at the so-called ‘optimal’ levels that are added to water for fluoridation. EPA lists fluoride as having “Substantial Evidence of Developmental Neurotoxicity.” Our children are already fluoride-overdosed.The rates of dental fluorosis have continued to rise since the early 2000s, as evident by the CDC’s 2011-2012 NHANES survey, which found that 57% of adolescents now have the condition, with a staggering 21% of adolescents displaying moderate fluorosis on at least two teeth, up from 2% in 1999-2004 Severe fluorosis has also increased, from < 1% to 2%. Dental fluorosis is white spotted, yellow, brown and/or pitted teeth which occurs when children consume too much fluoride while their teeth are forming. We can't see what fluoride is doing to brains and bones. When fluoridation began, there was no thought that fluoride would get into the brain. That information alone should signal the death knell for fluoridation; but we will continue to use our children as guinea pig in this ongoing experiement

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