The issue of artificial fluoridation of water is complicated by the high fluoride levels in the diet and in beverages. Since World War II the use of both organic and inorganic fluoride compounds in industry has burgeoned, as has industrial fluoride pollution. You cannot burn a piece of coal without liberating fluoride. Even fluoride dust taken in through the lungs can lead to dental fluorosis. Natural fluoride, cryolite, a sodium aluminium fluoride, is used in aluminium production, and apatite, a calcium and fluoride containing phosphate complex, is used as the raw material for phosphate fertilizers. Fluorides have also been used for many years as insecticides and rodenticides, the latter being the reason many opponents still like to describe fluoride as a "rat poison".
Fluorine has been introduced into pharmaceutical drugs including steroids, the synthetic oestrogens used in the Pill and, most recently, antibiotics.Fluorinated anaesthetics often called "halogenated" anaesthetics can give off high concentrations of inorganic fluorides when metabolized in the liver, according to Professor Philippe Grandjean, a top international fluoride expert and WHO scientist, from the Institute of Community Health, Odense University, Denmark.
An apple contains between 0.22 and 1.30 ppm fluoride, according to the World Health Organization, but the fluorine containing insecticide sprayed on the tree producing the apple may add another 1 mg of fluoride to it and to your bodily load.
In Fluoridation: The Great Dilemma (Coronado Press, Kansas, 1978) Dr George Waldbott, among others, warned that baby foods can contain up to 18 ppm fluoride, enough to produce mottled teeth, and that fish protein concentrate distributed to people in the Third World may contain up to 370 ppm. Others, such as the British dentist Dr Geoffrey E Smith, now living in Australia, point out that infant milk formulae made up with fluoridated water can contain up to 100 times the amount of fluoride obtained from mother's milk. Even fluoride preservatives in cheap wines have been shown to cause wine fluorosis in heavy drinkers, according to an oft quoted paper by M. Soriano from the University of Barcelona in 1966.
Modern estimates of dietary fluoride intakes by fluoride promoters tend to hark back to a 1943 study done by F J McClure of the American National Institute of Dental Research. He found that the typical American adult obtained between 0.3 and 0.5 mg of fluoride a day from food. Independent scientists such as the late John Marier of the Division of Biological Sciences at the National Research Council of Canada claim that diet alone may contribute up to 5.5 mg fluoride a day.
The average consumer would be hard put to judge his or her fluoride intake today. Official guidelines on "optimal" doses for dental purposes, on "safe and adequate" doses, and even on toxic and lethal levels, are also confusing and can vary from country to country, and from one scientific or academic institution to another.
"Fluoride," wrote Canada's John Marier in a major fluoride report in 1977, "is a persistent bioaccumulator, and is entering into human food and beverage chains in increasing amounts."
Some of the fluoride ingested may be stored in bone for a long time before being slowly released. The half life, or average turnover rate, can be as much as nine years, which means that both dental and medical effects can be caused by much earlier exposure, and need not be related to the toothpaste, tablets or drinking water being used when the symptoms appear.
There is also the problem of biotransformation in the body, whereby organic fluorine compounds belonging to the fluorocarbon group can release inorganic fluorides through bacterial metabolism and degradation.
For many years these fluorinated hydrocarbons were regarded as stable and inert. Today, however, many scientists in fields such as organic chemistry insist that few organo fluorine compounds are biologically stable.
Magnesium is at the very centre of the body's reactions to fluoride from all sources. Fluoride "chelates" (chemically "grabs") magnesium in the body, making the magnesium unavailable for its many functions. Magnesium in turn, protects against fluoride toxicity.
As John Marier put it in a paper presented to dentists at the University of Kuopio in Finland in 1979, ". . . the toxic effects of fluoride [are] a direct function of the severity of the magnesium deficiency. Thus, very low levels of dietary fluoride are toxic at ultra low levels of dietary magnesium, whereas much higher levels of fluoride are innocuous when dietary magnesium is increased."
It is plain that many people consume quite high amounts of fluoride from both natural and industrial sources without developing mottled teeth or fluoride related medical afflictions.
The reason is that fluoride can be chelated not only by magnesium but by other naturally occurring metals, which means that its bioavailability is low.