Fluoride
A fluoride is a binary compound of fluorine with another element or radical. Examples of common fluoride compounds include hydrofluoric acid (HF), and sodium fluoride (NaF).
Uses
Fluoride compounds are used in a wide range of applications.
Where instead used in very low concentrations (on the order of parts per million), fluorides are used in human health applications; specifically, fluorides such as sodium fluoride (NaF), sodium monofluorophosphate (SMFP), stannous fluoride (SnF2), and amine fluoride are common ingredients in toothpaste. Many dentists also give their patients semiannual fluoride treatments.
Similarly, many North American municipalities also fluoridate their water supplies, citing effectiveness in reducing tooth decay, safety of fluoridation, and the low cost to do so. The American Dental Association, World Health Organization, and some other health organizations recommend fluoridation of municipal water supplies to a level between 0.7 and 1.2 ppm.
When used in very high concentrations (on the order of 10% by volume or higher) , sodium fluoride may be found in rat poisons, insecticides, and wood preservatives.
Fluorides and human health
High concentrations
In high concentrations, as with almost all substances, fluoride compounds are toxic. 5 grams of full strength sodium fluoride will kill most adult humans; a lethal dose is approximately 75mg per kilogram body mass. When ingested directly, fluoride compounds are readily absorbed by the intestines; over time, the compound is excreted through the urine, and the half life for concentration of fluorine compounds is on an order of hours. (But declining concentration indicates only that fluorine is going "out of circulation"; partially expelled, but partially bound in bone, etc.) Urine tests are a good indication of high exposure to fluoride compounds in the recent past.
In 1973 Jason Burton, a boy in Melbourne, Australia died after swallowing six fluoride tablets; four were recovered after a stomach pumping while the other two had already been absorbed into the body. The hospital staff had assumed it would take well over 100 tablets to be lethal.[1]
High concentration salts of fluorine are toxic if swallowed or inhaled. (In October 1948 Donora, Pennsylvania had an incident of fluoride poisoning as a result of a temperature inversion in a valley of zinc and steel works; 20 died.[2]) Contact by such compounds with skin or eyes is dangerous. In case of accidental swallowing, give milk, calcium carbonate or milk of magnesia to slow absorption. Eye or skin contact should be treated by removing any contaminated clothing and flushing with water.
Low concentrations
Fluoride is best known for its use in small quantities to help improve reduce cavity frequency in teeth. A debate continues about whether fluoride ions (F-) are a trace element beneficial to humans for other reasons. Health Canada's current stance is that fluorides are beneficial to teeth, but that other physiological benefits are unproven.[[3] p3])
Fluoride compounds, usually calcium fluoride, are naturally found in low concentration in drinking water and some foods, like tea. Fluoride ions replace Calcium ions in Calciumhydroxyapatite in teeth, forming Fluorohydroxyapatite, which is more chemically stable and dissolves at a pH of 4.5, compared to 5.5 pH for Calciumhydroxyapatite. This is generally believed to lead to fewer cavities, since stronger acids are needed to attack the tooth enamel.
The only generally accepted adverse effect of low concentration fluoridation at this time is fluorosis. It is a condition caused by 'excessive' intake of fluorine compounds over an extended period of time, and can cause yellowing of teeth, or brittling of bones and teeth. The definition of 'excessive' in the context of fluorosis falls on the order of parts per million and is generally accepted to mean significantly higher than the 0.7 to 1.2 ppm amounts the American Dental Association recommends for fluoridated water.
The case against fluoridation
Possible side effects of low concentration intake
Some scientific studies suggest that the use of fluorides, particularly silicofluorides (H2SiF6 and Na2SiF6), when over 2 ppm in water, has been implicated as a possible contributing factor in many cases of fetal damage, dental fluorosis, weakened bones and Alzheimer's Disease. Note that 2ppm is significantly higher than the American Dental Association's recommendation of 0.7 - 1.2 ppm in water supplies—but much less than is in one popular brand of bottled water.[4]
Even tiny amounts may have side effects. Florida International University found that peripheral-vision response delay increased by 0.5 s with just 0.5 mg NaF—that's about as much fluoride as would be in a pint of "optimally" fluoridated water.
Another study states that water fluoridation done with silicofluorides (as opposed to sodium fluoride, which does not show this effect) may cause higher lead absorbtion levels in children[5].
At least four separate large-scale studies totalling nearly half a million persons showed no net reduction in caries by fluoridation; other studies have shown the decline in caries has been occurring at statistically the same rate in fluoridated and unfluoridated areas.[6]
A large majority of epidemiological studies of fluoridation have found no adverse health effects. Critics point out these studies are usually funded by institutions with an interest in continuing fluoridation; that researchers (eg Phyllis Mullenix) have been fired for coming up with "fluoride is harmful" results, which discourages objectivity; and that the studies have been repeatedly shown to have flawed techniques or to have misrepresented or massaged their data.[7]
Industrial conspiracy
Critics of fluoridation charge that fluoride is deliberately associated with good health to protect many major industries, especially uranium, aluminum, and steel smelting, from the massive lawsuits that began to be filed in the 1930s for fluoride related damage to livestock, farms, and community health. Indeed, Dr. Robert Carton of the US EPA said "Fluoridation is the greatest case of scientific fraud of this century, if not of all time." (Marketplace CBC 1992 Nov 24).
Court cases
The issue of fluoridation has been the basis for many court cases. Anti-fluoride activists have sued cities for infringing upon their rights, and on the claim that fluoridation is a form of involuntary medication. Individuals have sued cities for a number of illnesses that they blamed on fluoridation of the city's water supply. In general courts have found in favour of cities in such cases and have not found a connection between health problems and flouride.
Cities and countries' choices on fluoridation
A 1998 ADA study asked the question Do you believe community water should be fluoridated? 70% said 'yes', and 18% said 'no', with the rest undecided. Health organizations and dentists that recommend water fluoridation point to studies which show statistically significant decreases in cavities where water fluoridation is done. There are other studies that have been performed that show no reduction or even increases in cavities. Thus the debate begins with through a sizable minority about whether fluoridation of water should be done.
The idea to fluoridate public water supplies was first introduced in the late 1940s. Debates began in many communities; ultimately, most decided to accept fluoridation. The first city to fluoridate its water was Grand Rapids, Michigan in 1945, as part of a ten year evaluation of flouridation. (The experiment was effectively terminated early, in 1951, with the imposition of fluoridation in the control group, Muskegon, Michigan.[8])
Unlike North America, less than 2% of Europe's population has fluoridated water. Sweden banned fluoridation in 1971 by mandate of their Supreme Court; Holland banned it constitutionally in 1976. West Germany rejected it in 1971; Norway, 1975; Denmark, 1977; France, 1980. In other places in the world, Chile rejected fluoridation in 1977; India and Egypt also have. Finland maintains an "experimental program" covering only 1½% of its people.[9] In Switzerland, only Basel's water was fluoridated, and that was stopped in April 2003 on the advice of their Health and Social Commission.[10],[11] Diesendorf "Mystery of Declining Tooth Decay" Nature 1986 points out "in western Europe where there is little fluoridation...large reductions in caries had been occurring in unfluoridated areas."—emphasis added)
In the United States, 45 cities abandoned the practice between 1990 and 1996. Gov. Pataki of New York signed on July 2, 1996 a law transferring the decision to fluoridate water from bureaucrats to elected officials.[12])
Secondary effects of fluoridation
In 1970, Grand Rapids, Michigan and Newburgh, New York had twice the United States average of dentists per capita (Anne-Lise Gotzsche The Fluoride Question, Panacea or Poison? p8). The ADA found in 1972 that dentists make 17% more profit in fluoridated areas as opposed to non-fluoridated areas (Douglas et al. "Impact of water fluoridation on dental practices and dental manpower" Journal of the American Dental Association 84:355-67, 1972). This could simply be a correlation between cities with fluoridated water having larger populations to serve, on the assumption that larger cities or water supplies are more likely to fluoridate their water. <someone should check that Gotzsche and ADA compared equivalent water supplies>
Conclusion on controversy
There are numerous studies dealing with water fluoridation. Some show that water fluoridation reduces cavities with no significant risk of other effects, when done at prescribed levels (this is what most North American communities accept as scientific fact). Others show a statistically significant increase in fluorosis when floridation is done (even while cavities are decreased). Still others show fluoridation providing no benefits at all.
An overriding concern with any fluoridation study, pro or against, is that the scientific method, and direct causation is established that cannot be otherwise explained.
In any event, the controversy over fluoridation's effects (positive or negative) on the public health is unlikely to end soon.
External Links
Pro fluoridation
- American Dental Association, on Fluoride -- needs JavaScript
- American Council on Science and Health
- Dihydrogen Monoxide Homepage
Anti fluoridation
- The Fluoride Action Network
- Fluoride: Protected Pollutant or Panacea?
- Genung Dentistry
- Fluoride: Commie Plot or Capitalist Ploy
- Chinese studies show fluoride correlates with mental impairment
- Fluoride—Worse Than We Thought puzzles how one single 1999 CDC report says the systemic application of fluoride is a good thing while acknowledging its benefits derive from topical use
- Counterindicative citations with texts
- Val Valerian's Chronology of Fluoride
- 150+ Fluoride facts, horror stories, and coverups
- Suite101, fluoridation section
- High-responsibility dental professionals and former profluoridationists who changed their minds, and why: John Colquhoun, Hardy Limeback
- Erb & Erb The Slow Poisoning of America[13] Mostly about glutamates, but begins with fluoride
- Highlights in North American Litigation During the 20th Century on Artificial Fluoridation of Water Supplies