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Fluoride: Poisoning the Well

Cynthia F. Hodges, JD, LLM, MA

Watch video: Fluoride: Poisoning the Water "for Your Teeth"

Many municipalities add fluoride to drinking water, ostensibly to prevent tooth decay. This amounts to making fluoride, the active toxin in rat poisons and cockroach powder, a compulsory medication. Fluoride poses a significant risk to the public health. These risks include thyroid gland suppression and cancer risk, dental fluorosis, risk to brain and bone health, and more.
Other countries have granted their citizens the right to choose or refuse adding fluoride to their diets. 97% of Western Europe has chosen fluoride-free water. Rather than forcing fluoride treatment on the whole population, western Europe allows individuals the right to choose, or refuse, fluoride. For example, in Luxembourg, the official position is that “drinking water isn't the suitable way for medicinal treatment and that people needing an addition of fluoride can decide by their own to use the most appropriate way.” According to comprehensive data from the World Health Organization, the tooth decay rates in Western Europe are often lower than in the US.

Fluoride has very little benefit and serious risks when ingested. Proponents of fluoride may believe in its effectiveness, but a growing number of studies question that belief. According to a review published by the Ontario Ministry of Health and Long Term Care, “The magnitude of [fluoridation's] effect is not large in absolute terms, is often not statistically significant and may not be of clinical significance.” The Centers for Disease Control stated that fluoride's “predominant effect is posteruptive and topical.” Any benefits obtained from the use of fluoride come from the direct application of fluoride to the outside of teeth and not from ingestion. 

Fluoride’s ability to fight cavities when orally ingested seems to have been greatly exaggerated. Dr. John Yiamouyiannis examined raw data from a study that was conducted by the National Institute for Dental Research (NIDR), and concluded that fluoride did not appear to have any decay preventing success. He found little difference in the DMFT values (the mean number of decayed, missing or filled teeth) for approximately 40,000 children, regardless of whether they grew up in fluoridated, non-fluoridated or partially fluoridated communities. [1] Another study conducted by the New Zealand National Health Service plan examined the teeth of every child in key age groups, and found that the teeth of children in non-fluoridated cities were slightly better than those in the fluoridated cities. [2] Cavities do not increase when fluoridation stops. Several studies published since 2000 have reported no increase in tooth decay in communities that have ceased fluoridation.

Ingestion of fluoride endangers public health. The most recognized problem is dental fluorosis, which is characterized by the failure of tooth enamel to crystallize properly in permanent teeth. The chemicals used to fluoridate drinking water - fluorosilicic acid, sodium silicofluoride, and sodium fluoride - are industrial waste products from the phosphate fertilizer industry. Of these chemicals, fluorosilicic acid (FSA) is the most widely used. FSA is a corrosive acid that has been linked to higher blood lead levels in children. A study from the University of North Carolina found that FSA can, in combination with chlorinated compounds, leach lead from brass joints in water pipes. Lead is a neurotoxin that can cause learning disabilities and behavioral problems in children.

Even in the absence of lead, ingesting fluoride is a risk to brain health. According to the National Research Council (NRC), fluoride can damage the brain. Animal studies conducted in the 1990s by EPA scientists found dementia-like effects at the same concentration (1 ppm) used to fluoridate water, while human studies have found adverse effects on IQ at levels as low as 0.9 ppm among children with nutrient deficiencies, and 1.8 ppm among children with adequate nutrient intake. In 1995, neurotoxicologist and former Director of toxicology at Forsyth Dental Center in Boston, Dr. Phyllis Mullenix, stated that, based on her research, fluoride acts in a way that lowers the I.Q. of children.
Small levels of fluoride can create “histologic lesions in [a child’s] brain similar to Alzheimer’s disease and dementia.” According to a study conducted by Varner et al., exposure to fluoride caused “damage to the blood brain barrier.” Studies dating back to the 1950s have shown links between Down's Syndrome and natural fluoridation. Ionel Rapaport showed how the age of women bearing Down's Syndrome children decreased in direct relation to the increase of fluoride in the water supply. The more fluoride that was in the water, the younger the age of the women bearing Down's Syndrome children.

If aluminum compounds are added to the water supply, they may also interact with fluoride to damage brain health. Aluminum may be absorbed by the body by combining with the fluoride. A study found that low levels of aluminum fluoride and sodium fluoride contained in “optimally” fluoridated water caused lesions to the brain similar to those found in Alzheimer's disease (in addition to severe kidney damage). Dr. Robert Isaacson, State University of New York, found that when aluminum fluoride is added to the food of rats, the rats developed short-term memory problems, smell sensory loss and other characteristics of Alzheimer's disease.

Fluoride ingestion also risks the health of the thyroid gland. According to the NRC, fluoride is an “endocrine disrupter,” and has warned that doses of fluoride of 0.01-0.03 mg/kg/day may reduce the function of the thyroid among individuals with low-iodine intake. “...[F]luoride affects normal endocrine function or response; the effects of the fluoride-induced changes vary in degree and kind in different individuals. Fluoride is therefore an endocrine disruptor in the broad sense of altering normal endocrine function or response... The mechanisms of action remain to be worked out and appear to include both direct and indirect mechanisms, for example, direct stimulation or inhibition of hormone secretion by interference with second messenger function, indirect stimulation or inhibition of hormone secretion by effects on things such as calcium balance, and inhibition of peripheral enzymes that are necessary for activation of the normal hormone.” [5] “Fluoride exposure in humans is associated with elevated TSH concentrations, increased goiter prevalence, and altered T4 and T3 concentrations; similar effects on T4 and T3 are reported in experimental animals...” [6] Fluoride was used for decades to suppress the thyroid gland in patients suffering from hyperthyroidism. Medicated dosages were frequently below the current “optimal” intake of 1 mg/day. Reduction of thyroid activity can lead to loss of mental acuity, depression and weight gain.

In addition to thyroid suppression, fluoride ingestion has been linked to thyroid cancer. Gladys Caldwell and Philip Zanfagna, MD, wrote in their book, Fluoridation and Truth Decay (1974), “A report in the 1955 New England Journal of Medicine shows a 400 percent increase in thyroid cancer in San Francisco during the period that the city has had fluoridated drinking water.” Also in 1974, Leo Kinlen of Oxford compared the occurrence of cancers in fluoridated and non-fluoridated areas. 100 thyroid cancer cases were observed compared to 81 expected ones, which represented an 18% increase.

Fluoride-ingestion also endangers bone health. Fluoride builds up in the bones and causes adverse changes to bone structure. According to the NRC, fluoride can diminish bone strength and increase the risk of bone fracture. The NRC noted that the best available information suggests that fracture risk may be increased at levels as low 1.5 ppm, which is only slightly higher than the concentration (0.7-1.2 ppm) added to water for fluoridation. Animal and human studies – including a study from a team of Harvard scientists – have found a connection between fluoride and a serious form of bone cancer (osteosarcoma) in males under the age of 20. Dr. William Marcus believes that a study conducted by Battelle for the National Toxicology Program on the toxicology of fluoride shows that there were dose-related increases in bone cancer in male rats. The Department of Health in New Jersey found that bone cancer in male children was between two and seven times greater in areas where water was fluoridated. U.S. Environmental Protection Agency (EPA) researchers confirmed the bone cancer-causing effects of fluoride at low levels. The connection between fluoride and osteosarcoma has been described by the National Toxicology Program as “biologically plausible.”

Fluoride also negatively affects enzymes, which can increase auto-immune diseases. Fluoride destroys enzymes by changing their shape. Enzymes (proteins) are necessary for various essential cellular functions. One way they do this is by having the exact shape necessary to fit like a key in a lock. Fluoride changes the shape of the enzymes so that they no longer fit. Once the enzymes have been changed, they appear foreign, and the body attacks them. This is an autoimmune reaction, since?the body is attacking itself.

Fluoridated water is not recommended for babies or kidney patients. In November of 2006, the American Dental Association (ADA) advised that parents should avoid giving babies fluoridated water. Other dental researchers have made similar recommendations over the past decade. Babies exposed to fluoride are at risk of developing dental fluorosis. Other tissues in the body may also be affected by exposure to fluoride. According to a recent review published in the medical journal, The Lancet, fluoride may damage the developing brain, causing learning deficits and other problems. There is also a risk to kidney patients. People with kidney disease have a heightened susceptibility to fluoride toxicity. The heightened risk stems from an impaired ability to excrete fluoride from the body. As a result, toxic levels of fluoride can accumulate in the bones, intensify the toxicity of aluminum build-up, and cause or exacerbate a painful bone disease known as renal osteodystrophy.

By forcing fluoride on everyone, many infants and other at-risk populations are harmed. Many people are now being over-exposed to fluoride. Americans are receiving fluoride from many other sources, such as fluoride dental products, fluoride pesticides, fluorinated pharmaceuticals, processed foods made with fluoridated water, and tea. As a result, many people are now exceeding the recommended daily intake, putting them at elevated risk of suffering toxic effects. According to the Journal of Public Health Dentistry, “Virtually all authors have noted that some children could ingest more fluoride from [toothpaste] alone than is recommended as a total daily fluoride ingestion.” Because of the increase in fluoride exposure from combined sources, the rate of dental fluorosis has increased significantly over the past 50 years. Whereas dental fluorosis used to affect fewer than 10% of children in the 1940s, the latest national survey found that it now affects over 30% of children.

Fluoridation is particularly burdensome and harmful to low-income communities. For example, low-income families are the least able to avoid fluoridated water due to the high costs of buying bottled water (which contributes to pollution) or expensive water filters. As a result, low-income families are least able to follow the American Dental Association’s (ADA) recommendation that infants should not receive fluoridated water. This may explain why African-American children have been found to suffer the highest rates of disfiguring dental fluorosis in the US. These low-income families are also at greater risk of fluoride toxicity. It has been established that individuals with inadequate nutrient intake have a significantly increased susceptibility to fluoride’s toxic effects. Since nutrient deficiencies are most common in low-income communities, and since diseases known to increase susceptibility to fluoride are most prevalent in low-income areas (e.g. end-stage renal failure), it is likely that low-income communities will be at greatest risk from suffering adverse effects associated with fluoride exposure. According to Dr. Kathleen Thiessen, a member of the National Research Council's review of fluoride toxicity, “I would expect low-income communities to be more vulnerable to at least some of the effects of drinking fluoridated water.”

As Western Europe has demonstrated, there are many equally effective and less-intrusive ways of delivering fluoride to people who actually want it. For example, topical fluoride products such as toothpaste and mouth rinses, which come with explicit instructions not to swallow, are readily available. Thus, for those individuals who wish to use fluoride, it is easy to find and inexpensive to buy. If some people cannot afford fluoride toothpaste, then the money saved by not fluoridating the water could be spent subsidizing topical fluoride products (or non-fluoride alternatives).

Watch video commentary about fluoride toxicity

Cynthia Hodges has a Doctor of Jurisprudence from South Texas College of Law in Houston, Texas, a Master’s of Law in Environmental and Natural Resources Law from Lewis & Clark Law School in Portland, Oregon, and a Master’s of Arts degree in Germanic Studies from the University of Texas at Austin.


1 Yiamouyiannis, J.A. “Water Fluoridation and Tooth Decay: Results from the 1986-87 National Survey of U.S. Schoolchildren,” Fluoride, 23, 55-67, 1990.
2 Colquhoun, J. “Child Dental Health Differences in New Zealand,” Community Healthy Services, XI 85-90, 1987.
3 “Neurotoxicity of Sodium Fluoride in Rats,” Mullenix, P. Neurotoxicology and Teratology, 17 (2), 1995
4 Isaacson, R. “Rat studies link brain cell damage with aluminum and fluoride in water” State Univ. of New York, Binghampton, NY, Wall Street Journal article by Marilyn Chase; Oct. 28, 1992, p. B-6.
5 National Research Council. “Fluoride in Drinking Water: A Scientific Review of EPA's Standards.” National Academies Press, Washington D.C. (2006) p. 223.
6 Id. at 218.

Watch video: Fluoride: Poisoning the Water "for Your Teeth"


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