Fluoride: A clinical, scientific perspective

To paraphrase Paracelsus, a medieval physician who was deemed the father of toxicology (the science of poisons), “everything is a poison—what differentiates a poison from a remedy is the dose.”  For example, two tablets of acetaminophen (Tylenol™) will relieve a headache or treat a fever, but the ingestion of 20 tablets may cause severe acute liver damage and even death.  The same rationale can be applied to the chemical fluoride, which I will explain based on a nearly 50 year career as a clinical toxicologist, professor and clinical scientist.  

My career included being the Director of two of the nation’s largest poison information centers in Minneapolis and Pittsburgh, a professor at the University of Minnesota College of Pharmacy and a professor in the Schools of Pharmacy and Medicine at the University of Pittsburgh and currently as a consultant clinical toxicologist.  I cite those positions to validate my experience and opinions regarding both the safety and benefits of fluoride, as well as an understanding of the adverse effects that can be associated with the fluoride ion.  During my clinical career I was responsible for managing in excess of 1.74 million potential poisoning exposure calls from anxious parents, workers and health care professionals who contacted the poison center for advice and treatment.  Hundreds of those exposures involved children who ingested excessive amounts of fluoride-containing toothpaste or mouthwash and sodium fluoride tablets that were prescribed for children and pregnant women who did not have the benefit of fluoridation in their public water supplies.  The academic side of my career included teaching medical professionals such as pharmacists, physicians, nurses and physician assistants about the recognition and management of poisoning emergencies.  As a clinical scientist I conducted toxicology research, published hundreds of papers in the medical and toxicology literature and served as a reviewer on the editorial boards of several medical journals.

As with all substances, some fluoride-containing compounds have harmful properties.  For example, hydrofluoric acid, which is used in the semi-conductor industry and as a common household (Whink™) and automotive rust remover, is extremely corrosive if it is not used properly and especially if the exposure involves the skin.  Most people are aware of the per- and polyfluoroalkyl group of chemicals, referred to as PFAS and forever chemicals, that are present in products such as stain and water-resistant fabrics, fire-fighting foams and Teflon cookware. There is significant concern about the long-term adverse health effects of PFAS.  Germane to this discussion is the presence of fluoride in some private wells.  When excessive amounts of fluoride are consumed chronically, exposed individuals may develop fluorosis, a condition that on the mild side may produce cosmetic mottling of dental enamel and on the severe side skeletal fluorosis which may be manifest by bone and joint problems, including brittle bones. 

Regarding the fluoridation of public water supplies, the Centers for Disease Control (CDC) have opined that “…fluoridation of drinking water as one of the ten great public health interventions of the 20th century.”  Furthermore, the “CDC promotes the safety and benefits of community water fluoridation as an effective, cost-efficient method for preventing tooth decay and improving oral health.”  Fluoridation of public water supplies is also endorsed by the American Dental Association.  While these prestigious health organizations encourage the use of fluoridation, it is not without controversy, as evidenced by the advisory referendum regarding continuing fluoridation of the Ladysmith water supply, an issue that will appear for voter consideration in the April 1 public election.  If fluoridation is used by a municipality in the U.S., the concentration deemed to be safe is 0.7 mg of fluoride per liter (33.8 ounces) of water.  Putting that into perspective consider that there are 5,000 mg of salt in a teaspoonful; therefore, the amount of fluoride is 0.00014 of a teaspoonful—a minute amount, but still efficacious to enhance dental health.  Based on the analysis of the Ladysmith water supply on March 10, 2025 by the Wisconsin State Laboratory of Hygiene, the fluoride concentration in Ladysmith water was 0.552 mg/liter or 0.00011 of a teaspoonful. Therefore, the Ladysmith water supply is managed safely and even slightly below the national standards.

When fluoridation was first introduced into U.S. municipal water supplies in the 1940’s, it was thought to reduce dental disease by 40-70%.  Now it is estimated that fluoridation reduces dental caries by 25%.  Why the apparent reduction in efficacy?  The answers are apparent due to the attention to improved dental hygiene, the presence of fluoride in many of the commercial beverages that we consume, the use of fluoride-containing toothpaste, prescription sodium fluoride tablets and professional application by dentists and dental hygienists.  Nearly every toothpaste that is available commercially contains 0.24% sodium fluoride.  The fluoride in toothpaste is only absorbed topically by the tooth enamel and helps to strengthen it.  The average person uses about 18 grams (slightly more than one-half an ounce) of toothpaste every month and that exposes them to approximately 42 mg of fluoride per month.  If toothpaste is swallowed the fluoride is absorbed, but in my 38 years as a poison center director, I did not observe any consequential toxicity, especially in children, unless they consumed a large amount of toothpaste which generally caused abdominal pain and diarrhea due to the presence of a noncaloric sweetener, sorbitol, that helps to flavor toothpaste.  In the most recent annual American Poison Centers National Poison Data System report, there were 7,401 exposures to fluoride-containing toothpaste by children ≤ five years of age and the report did not identify any serious outcomes in those children. 

The scientific literature is often misinterpreted by those who do not support the use of fluoridation.  One of the most frequently cited publications is a recent paper published in the Journal of the American Medical Association Pediatrics and entitled ‘Fluoride Exposure and Children’s IQ Scores-A Systematic Review and Meta-Analysis’.  The conclusion of the paper that opponents of fluoridation often cite is that fluoridation causes a decease in IQ scores of 1.63 points.  However, as a reviewer of hundreds of papers in the medical and toxicology literature in my career, the paper has serious limitations and flaws that do not support the conclusion to a reasonable degree of toxicological certainty.  The authors did not themselves conduct any research regarding the topic, but instead reviewed 74 papers and then summarized the results. Most importantly, not a single research study in the review was conducted in the U.S. and 45 of the 74 (61%) were from China, 14 from India and others from Iran, Taiwan, Pakistan, among other countries.  Additionally, only 13 of the 74 papers showed the average IQ decrease of 1.63 points.  A very important consideration is to determine the role that bias plays in these studies and 52 of the 74 (70%) were identified as having a high risk of bias which is highly suspect in any validated scientific study.  Studies should always have a control group; in this case there should have been a group that that was never exposed to fluoride and their IQs measured—there was no control group against which to compare their study group. In essence, did the control group have normal IQs?  Furthermore, there was absolutely no description as to whether the subjects were consuming well water, municipal water or whether they may have been ingesting fluoride from other sources.  Also, the age groups were not well delineated, nor was the socio-economic status of those who were studied described which would have an influence on the evaluation of IQ.  The most indicting aspect of the paper was that they found no association between reduced IQs and in individuals who were exposed to fluoride concentrations of less than 1.5 mg/liter of water.  The Ladysmith public water supply averages slightly more than 0.5 mg/liter of water, which is well within the safe range of this widely cited paper. Similarly, the often-cited National Toxicology Program paper failed to identify a correlation between IQ and consuming fluoridated water at the recommended concentration of 0.7 mg/liter.

In summary, my decades of experience as a clinical toxicologist and clinical scientist, give me 100% assurance that proper fluoridation of the public water supply is safe and effective and advantageous to all who consume water from the City of Ladysmith.  Furthermore, eliminating fluoride from the public water supply would have undue effects on the disadvantaged residents of Ladysmith who do not have the financial resources to provide adequate dental hygiene and care for their children.