San Diegans for Safe Drinking Water

Each year there are thousands of reports to Poison Control centers in the United States related to excessive ingestion of fluoride toothpastes, mouthrinses, and supplements.

Water fluoridation accidents, resulting in excess levels of fluoride in water, have been one of the sources of acute fluoride poisoning.

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.

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.

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’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.

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.

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.

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 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.