“Over the past ten years a large body of peer-reviewed science has raised concerns that fluoride may present unreasonable health risks, particularly among children, at levels routinely added to tap water in American cities,” Environmental Working Group, July 2005.
“In summary, we hold that fluoridation is an unreasonable risk.” US Environmental Protection agency Headquarters Union 2001.
“Carefully conducted studies of exposure to fluoride and emerging health parameters of interest (e.g., endocrine effects and brain function) should be performed in populations in the United States exposed to various concentrations of fluoride” US National Research Council, 2006
“I am quite convinced that water fluoridation, in a not-too-distant future, will be consigned to medical history.” Dr. Arvid Carlsson, Pharmacologist, Nobel Laureate in Physiology and Medicine, 2000.
Fluoride Accidents & Poisonings
Fluoride, the active ingredient in many pesticides and rodenticides, is a powerful poison – more acutely poisonous than lead. Because of this, accidental over-ingestion of fluoride can cause serious toxic symptoms. Each year there are thousands of reports to Poison Control centers in the United States related to excessive ingestion of fluoride toothpastes, mouth rinses, and supplements. Water fluoridation accidents, resulting in excess levels of fluoride in water, have been one of the sources of acute fluoride poisoning.
Fluoride & Dental Fluorosis
Excessive ingestion of fluoride during the early childhood years can damage the tooth-forming cells, leading to a defect in the enamel known as dental fluorosis. Teeth impacted by fluorosis have visible discoloration, ranging from white spots to brown and black stains. According to the Centers for Disease Control, 32% of American children now have some form of dental fluorosis, with 2 to 4% of children having the moderate to severe stages (CDC 2005).
According to Dr. Hardy Limeback, Head of Preventive Dentistry at the University of Toronto, “it is illogical to assume that tooth enamel is the only tissue affected by low daily doses of fluoride ingestion.
Fluoride & The Gastrointestinal Tract
Among people hypersensitive to fluoride, gastrointestinal ailments have been produced following ingestion of 1 mg tablets of fluoride or consumption of 1 ppm fluoridated water. A single ingestion of as little as 3 mg of fluoride, in carefully controlled clinical trials, has been found to produce damage to the gastric mucosa in healthy adult volunteers. No research on the gastric mucosa has ever been conducted to determine the effect of lower doses with repeated exposure.
Fluoride & Allergy / Hypersensitivity
As acknowledged by the Physicians’ Desk Reference, some individuals are allergic/hypersensitive to fluoride. The largest, government-funded, clinical trial found that 1% of individuals exposed to 1 mg/day of fluoride exhibited allergic/hypersensitive reactions, including skin reactions, gastric distress, and headache.
Fluoride & The Kidneys
The kidneys play a vital role in preventing the build-up of excessive fluoride in the body. Among healthy individuals, the kidneys excrete approximately 50% of the daily fluoride intake. However, among individuals with kidney disease, the kidneys’ ability to excrete becomes markedly impaired, resulting in a build-up of fluoride within the body. It is well recognized that individuals with kidney disease have a heightened susceptibility to the cumulative toxic effects of fluoride. Of particular concern is the potential for fluoride, when accumulated in the skeletal system, to cause, or exacerbate, renal osteodystrophy – a bone disease commonly found among people with advanced kidney disease.
In addition, fluoride has been definitively shown to poison kidney function at high doses over short-term exposures in both animals and humans. The impact of low doses of fluoride, given over long periods of time, has been inadequately studied. A recent animal study, conducted by scientists at the US Environmental Protection Agency (Varner 1998), reported that exposure to just 1 ppm fluoride caused kidney damage in rats if they drank the water for an extended period of time, while a new study from China found an increased rate of kidney disease among humans consuming more than 2 ppm (Liu 2005). Hence, the adverse effects to kidney function that fluoride causes at high doses over short periods of time, may also be replicated with small doses if consumed over long periods of time.
Kidney disease markedly increases an individual’s susceptibility to fluoride toxicity. The kidneys are responsible for ridding the body of ingested fluoride, and thereby preventing the buildup of toxic levels of fluoride in the body. In healthy adults, the kidneys are able to excrete approximately 50% of an ingested dose of fluoride.
However, in adults with kidney disease the kidneys may excrete as little as 10 to 20% of an ingested dose – thus increasing the body burden of fluoride and increasing an individual’s susceptibility to fluoride poisoning (e.g. renal osteodystrophy).
The bone changes commonly found among patients with advanced kidney disease closely resemble the bone changes found among individuals with the osteomalacic-type of skeletal fluorosis. This raises the possibility that some individuals with kidney disease are suffering from undiagnosed skeletal fluorosis.
As noted by Dr. Edward Groth, a veteran Senior Scientist at Consumers Union:
“It seems probable that some people with severe or long-term renal disease, which might not be advanced enough to require hemodialysis, can still experience reduced fluoride excretion to an extent that can lead to fluorosis, or aggravate skeletal complications associated with kidney disease… It has been estimated that one in every 25 Americans may have some form of kidney disease; it would seem imperative that the magnitude of risk to such a large sub-segment of the population be determined through extensive and careful study. To date, however, no studies of this sort have been carried out, and none is planned” (Groth 1973; Doctoral Thesis; Stanford University).
Because the kidney accumulates more fluoride than all other soft tissues (with the exception of the pineal gland), there is concern that excess fluoride exposure may contribute to kidney disease – thus initiating a “vicious cycle” where the damaged kidneys increase the accumulation of fluoride, causing in turn further damage to the kidney, bone, and other organs. The possibility that fluoride exposure can cause direct damage to kidney tissue is supported by a long line of animal and human studies. In studies on fluoride-exposed animals, kidney damage has been reported at levels as low as 1 ppm if the animals consume the water for long periods of time.
In humans, elevated rates of kidney damage are frequently encountered among populations with skeletal fluorosis. In addition, several case reports suggest that some individuals with kidney disease can experience significant recovery in their clinical signs and symptoms following the provision of fluoride-free water.
Fluoride & The Brain
Fluoride’s ability to damage the brain represents one of the most active areas of research on fluoride toxicity today.
Concern about fluoride’s impact on the brain has been fueled by 18 human studies (from China, Mexico, India, and Iran) reporting IQ deficits among children exposed to excess fluoride, by 4 human studies indicating that fluoride can enter, and damage, the fetal brain; and by a growing number of animal studies finding damage to brain tissue (at levels as low as 1 ppm) and impairment of learning and memory among fluoride-treated groups.
According to the US National Research Council, “it is apparent that fluorides have the ability to interfere with the functions of the brain.”
- Fluoride’s ability to damage the brain represents one of the most active areas of research on fluoride toxicity today.
- The research on fluoride and the brain has been fueled by 18 human studies from China, India, Iran, and Mexico finding elevated levels of fluoride exposure to be associated with IQ deficits in children. Fluoride’s impact on IQ is exacerbated among children with low-iodine exposure.
- The impact of fluoride on children’s IQ has been documented even after controlling for children’s lead exposure, iodine exposure, parental education and income status, and other known factors that might impact the results (Rocha-Amador 2007; Xiang 2003 a,b).
- In addition to IQ studies, 3 studies (Yu 1996; Du 1992; Han 1989) have found that fluoride accumulates in the brain of the fetus, causing damage to cells and neurotransmitters and 1 study (Li 2004) has found a correlation between exposure to fluoride during fetal development and behavioral deficits among neonates.
- Several recent studies have found that even adult exposures to fluoride may result in central nervous system disturbances, particularly among industrial workers.
- The findings of neurological effects in fluoride-exposed humans is consistent with, and strengthened by, recent findings from over 40 animal studies published since 1992. As with the studies on humans, the studies on animals have reported an impairment in learning and memory prorcesses among the fluoride-treated groups.
- The animal studies have also documented considerable evidence of direct toxic effects of fluoride on brain tissue, even at levels as low as 1 ppm fluoride in water (Varner 1998). These effects include:
- Reduction in nicotinic acetylcholine receptors;
- Reduction in lipid content;
- Impaired anti-oxidant defense systems;
- Damage to the hippocampus;
- Damage to the purkinje cells;
- Increased uptake of aluminum;
- Formation of beta-amyloid plaques (the classic brain abnormality in Alzheimer’s disease);
- Exacerbation of lesions induced by iodine deficiency; and
- Accumulation of fluoride in the pineal gland.
Fluoride & The Pineal Gland
In the 1990s, it was discovered that the pineal gland is a major site of fluoride accumulation within the body – with higher concentrations of fluoride than either teeth or bone. Subsequent animal studies indicate that the accumulation of fluoride in the pineal gland can reduce the gland’s synthesis of melatonin, a hormone that helps regulate the onset of puberty. Fluoride-treated animals were found to have reduced levels of circulating melatonin and an earlier onset of puberty than untreated animals. The scientist who conducted the research concluded:
“The safety of the use of fluorides ultimately rests on the assumption that the developing enamel organ is most sensitive to the toxic effects of fluoride. The results from this study suggest that the pinealocytes may be as susceptible to fluoride as the developing enamel organ” (Luke 1997).
The fact that fluoride’s impact on the pineal gland was never studied, or even considered, before the 1990s, highlights a major gap in knowledge underpinning current policies on fluoride and health. According to the US National Research Council, “any agent that affects pineal function could affect human health in a variety of ways, including effects on sexual maturation, calcium metabolism, parathyroid function, postmenopausal osteoporosis, cancer, and psychiatric disease.”
Fluoride & The Thyroid Gland
According to the US National Research Council, “several lines of information indicate an effect of fluoride exposure on thyroid function” – particularly among individuals with an iodine deficiency.
Fluoride’s potential to impair thyroid function is most clearly illustrated by the fact that — up until the 1970s — European doctors used fluoride as a thyroid-suppressing medication for patients with hyperthyroidism (over-active thyroid). Fluoride was utilized because it was found effective at reducing the activity of the thyroid gland – even at doses as low as 2 mg/day.
Today, many people living in fluoridated communities are ingesting doses of fluoride (1.6-6.6 mg/day) that fall within the range of doses (2 to 10 mg/day) once used by doctors to reduce thyroid activity in hyperthyroid patients. This is of particular concern considering the widespread problem of hypothyroidism (under-active thyroid) in the United States. Symptoms of hypothyroidism include obesity, lethargy, depression, and heart disease.
Fluoride & Bone Disease
Excessive exposure to fluoride is well known to cause a bone disease called skeletal fluorosis. Skeletal fluorosis, especially in its early stages, is a difficult disease to diagnose, and can be readily confused with various forms of arthritis including osteoarthritis and rheumatoid arthritis. In its advanced stages, fluorosis can resemble a multitude of bone/joint diseases. In individuals with kidney disease, fluoride exposure can contribute to, and/or exacerbate, renal osteodystrophy.
Fluoride & Bone Fractures
The majority of animal studies investigating fluoride’s effect on bone strength, have found fluoride to either have no effect or a negative effect on strength. According to the US National Research Council, “The weight of evidence indicates that, although fluoride might increase bone volume, there is less strength per unit volume.”
Studies on human populations consuming fluoride in drinking water have found an association between dental fluorosis and increased bone fracture in children; and between long-term consumption of fluoridated water and increased hip fracture in the elderly.
Carefully conducted human clinical trials – including two “double-blind trials” – have found that fluoride (at doses of 18-34 mg/day for just 1-4 years) increases the rate of bone fracture, particularly hip fracture, among osteoporosis patients.
Fluoride & Cancer
According to the National Toxicology Program, “the preponderance of evidence” from laboratory ‘in vitro’ studies indicates that fluoride is a mutagenic compound. Many substances which cause mutagenic damage also cause cancer..”
While the concentrations of fluoride causing mutagenic damage in laboratory studies are higher than the concentrations found in human blood, there are certain “microenvironments” in the body (e.g. the bones and the bladder) where the concentrations of fluoride can accumulate to levels comparable to, or in excess of, those causing mutagenic effects in the laboratory.
Fluoride has been found to cause bone cancer (osteosarcoma) in government animal studies and rates of osteosarcoma among young males living in fluoridated areas have been found to be higher than young males living in unfluoridated areas. Osteosarcoma, while rare, is a very serious cancer. Children who develop osteosarcoma face a high probability of death (usually within 3 years) or amputation.
Fluoride exposure has also been linked to bladder cancer – particularly among workers exposed to excess fluoride in the workplace. According to the US National Research Council, “further research on a possible effect of fluoride on bladder cancer risk should be conducted.”
According to the National Toxicology Program, “the preponderance of evidence” from laboratory ‘in vitro’ studies indicates that fluoride is a mutagen (a compound that can cause genetic damage).
It is generally accepted that if a substance can induce genetic damage there is a heightened risk that it could cause cancer as well.
While the concentrations of fluoride causing mutagenic damage in the in vitro studies is higher than the concentrations found in human blood, there are certain “microenvironments” in the body (e.g. the bones) where the concentrations of fluoride can accumulate to levels comparable to, or in excess of, those causing mutagenic effects in the laboratory.
Of particular concern are a series of studies indicating that fluoride can cause osteosarcoma (bone cancer) in both fluoride-treated male rats and boys under the age of 20 living in fluoridated areas. Osteosarcoma is a rare, but deadly, form of cancer that strikes primarily during the teenage years.
Of additional concern are recent studies indicating that:
- Primates (humans and great apes) are more susceptible to the mutagenic effects of fluoride than rodents (rats);
- An increased rate of mutagenic damage was detectable in humans exposed to only modestly elevated levels of fluoride; and
- Workers exposed to fluoride in industry – in the absence of other known carcinogens such as PAH – suffered an increased occurrence of bladder cancer.
Fluoride & Tooth Decay (Caries)
According to the current consensus view of the dental research community, fluoride’s primary – if not sole – benefit to teeth comes from TOPICAL application to the exterior surface of teeth, not from ingestion.
Perhaps not surprisingly, therefore, tooth decay rates have declined at similar rates in all western countries in the latter half of the 20th century – irrespective of whether the country fluoridates its water or not. Today, tooth decay rates throughout continental western Europe are as low as the tooth decay rates in the United States – despite a profound disparity in water fluoridation prevalence in the two regions.
Within countries that fluoridate their water, recent large-scale surveys of dental health – utilizing modern scientific methods not employed in the early surveys from the 1930s-1950s – have found little difference in tooth decay, including “baby bottle tooth decay”, between fluoridated and unfluoridated communities.
“[T]he political profluoridation stance has evolved into a dogmatic, authoritarian, essentially antiscientific posture, one that discourages open debate of scientific issues.” – Dr. Edward Groth, Senior Scientist, Consumers Union, 1991.
“Journal editors often have refused for political reasons to publish information that raises questions about fluoridation. – Chemical & Engineering News, August 1, 1988.
“We are left with compelling evidence that powerful interests with high financial stakes have colluded to prematurely close honest discussion and investigation into fluoride toxicity.” – Dr. Sheldon Krimsky, Tufts University, August 16, 2004.
“The Public Health Service, unfortunately, has locked itself into a position where it has made this statement on the record that there is absolutely no hazard to fluoridating public water supplies and the matter is closed. Now, that, of course, is immediately an unscientific approach – Ralph Nader, Consumer Advocate, 1971.