by Paul Connett
PART FOUR
The Evidence of Harm
As we have seen in the previous chapters, there are many arguments against the practice of water fluoridation that, in and of themselves, should persuade a conscientious decision maker not to endorse it. For some people, establishing that fluoridation is an unethical and poor medical practice is sufficient to support an end to the practice (chapters 1–2). Some are appalled that the chemicals used in fluoridation of the water are not pharmaceutical grade but a hazardous industrial waste (chapter 3). Many are further shocked that no U. S. federal agency accepts responsibility for the practice or the chemicals used (chapter 4). For others, a deciding factor is that the evidence that swallowing fluoride reduces tooth decay is weak (chapters 6–8).
In addition to all these reasons for rejecting fluoridation, perhaps the ultimate one for most opponents is that the practice may cause harm. If evidence can be found that fluoridation involves health risks, the case against it becomes overwhelming. In this respect, we would do well to remember the Hippocratic admonition, “First, do no harm. ”
In the following pages, we look at fluoride’s potential to damage the teeth (dental fluorosis, chapter 11); the brain (chapter 15); the endocrine system, including the thyroid and pineal glands (chapter 16); bone (including fractures, arthritis, and osteosarcoma, chapters 17 and 18); and the kidney and other tissues (chapter 19). Chapter 12 summarizes the kind of information that a toxicologist would want to have before making a weight-of-evidence judgment about the safety of a chemical before exposing an individual or population. In chapter 13, we examine the evidence that a small percentage of the population may be particularly sensitive to fluoride’s toxic effects, exhibiting a number of reversible symptoms that clear up when the source of fluoride is removed. Chapter 14 describes a major recent event in the science of this matter: publication of the report of the U. S. National Research Council of the National Academies, Fluoride in Drinking Water: A Review of EPA’s Standards.
Before reviewing the evidence of health effects, however, we must stress the important difference between the possible health effects caused by fluoride and those caused by fluoridation. There is no doubt at all about the former; the debate rages over the latter.
The one area of harm even the most ardent promoter of fluoridation cannot deny is dental fluorosis, and that is where our review of fluoride’s adverse health effects begins.
•
11 •
Dental Fluorosis
Coauthored with Peter Meiers
Dental fluorosis is a mottling and discoloration of the tooth enamel. Fluoride in drinking water was identified as the cause of this condition in three independently published studies in 1931. 1–3 Also in 1931, soon after these reports were published, Alcoa scientists were finding cases of dental fluorosis near the company’s aluminum smelters where there was little or no fluoride in the water (e. g. Massena, New York). 4 In 1932, Dr. H. Trendley Dean, from the Dental Section of the U. S. Public Health Service, began his survey of the whole United States for this condition. In a 1934 article, he classified dental fluorosis according to the following categories: questionable, very mild, mild, moderate, moderate to severe, and severe. The article included an artist’s rendition of the categories. 5 In a later article he provided black-and-white photographs. 6
Although there have been other attempts to define the various stages of this condition, Dean’s classification is still used widely, although the categories “questionable” and “moderate to severe” have tended to drop out of common use. Dean described the four main categories very precisely by the percentage of the enamel impacted:
• Very mild dental fluorosis involves opaque white patches or streaks ranging from small areas on the cusps of the teeth up to 25 percent of the tooth surface.
• Mild dental fluorosis involves an impaction of up to 50 percent of the tooth surface.
• Moderate dental fluorosis involves 100 percent of the tooth surface being affected, with some pitting.
• Severe dental fluorosis affects 100 percent of the tooth surface with more pitting and brittleness.
In time, especially with the moderate and severe categories, the white patches become progressively discolored, going from yellow to orange to brown, making the condition even more unsightly. The percentage of children affected by this condition steadily increases with the level of fluoride in the water in a very close to linear fashion (see figure 7. 3).
By 1936, Dean was reporting that two hundred areas in the United States—many clustered in Arizona, Colorado, Illinois, Iowa, New Mexico, South Dakota, and Texas—had endemic mottled enamel and in another one hundred areas it had been reported but not yet confirmed by survey. These three hundred areas were distributed among twenty-three states. 7 By 1938, he was reporting that a “higher percentage of caries-free children is found in cities whose water supplies contain relatively toxic amounts of fluoride than in those communities with water supplies not so affected, ” but he warned that “the possibility of partially controlling dental caries through the domestic water supply warrants thorough epidemiological-chemical study. ”8 His famous twenty-one-city study would not appear for another four years. 9, 10
Percentage of Children Affected
Dean believed that with fluoride at 1 ppm in the drinking water, dental fluorosis would affect only about 10 percent of children, and then only in its very mild form. When it came to artificial water fluoridation, he felt that any level of fluorosis above the very mild level was unacceptable. In 1952, this is what Dean had to say in his testimony before the Delaney Committee of the U. S. Congress: “We don’t want any ‘mild’ [fluorosis] when we are talking about fluoridation. We don’t want to go that high and we don’t have to go that high. . . I don’t want to recommend any fluoridation where you get any ‘mild. ’”11
Dean’s comments on the unacceptability of mild (and thus moderate and severe) dental fluorosis as a trade-off for “any advantage that might accrue from the partial control of dental caries”12 are in sharp contrast to what fluoridation promoters say today. The latter accept both mild and moderate dental fluorosis, and become concerned only when the condition reaches the severe stage.
Modern Surveys of Dental Fluorosis
In 1997, Heller, Eklund, and Burt reported on the findings of a 1986–1987 survey conducted by the National Institute of Dental Research (NIDR) in the United States. 13 They revealed that 29. 6 percent of children in artificially fluoridated areas (0. 7–1. 2 ppm) had dental fluorosis on at least two teeth (see table 11. 1). In those communities, 22. 5 percent of the children had very mild, 5. 8 percent had mild, and 1. 3 percent had moderate dental fluorosis. 14 This breakdown by severity level is shown in table 11. 2. The figure for all levels combined (29. 6 percent) is three times the rate anticipated by Dean, and, of course, not all of the fluorosis was in the very mild category.
Heller et al. also found that about 21. 6 percent of children in non-fluoridated areas (0. 3–0. 7 ppm) had dental fluorosis, as did about 13. 6 percent of children in communities with less than 0. 3 ppm. 15 Tables 11. 1 and 11. 2 summarize Heller’s findings.
The York Review panel estimated that up to 48 percent of children in “optimally” fluoridated areas worldwide have dental fluorosis in all forms, with 12. 5 percent showing abnormalities of aesthetic concern. 16
Source: Heller et al. , 17 using data from the NIDR survey of U. S. children in 1986-1987.
Source: Heller et al. , 18 using data from the NIDR survey of U. S. children in 1986-1987.
In 2005, the Centers for Disease Control (CDC) released the findings of Beltrán-Aguilar et al. of a new national survey of oral health in the United States conducted during the years 1999–2002 as part of the National Health and Nutrition Examination Survey (NHANES). The survey found an overall dental fluorosis rate of 32 percent among U. S. schoolchildren aged six to nineteen years. Incredibly, 3–4 percent of American children have dental fluorosis in the combined moderate and seve
re categories. These figures include children living in both fluoridated and non-fluoridated communities. According to the CDC, the 32 percent total represented an increase of 9 percent over the previous national survey, in 1986–1987. 19
Black American Children Are More Vulnerable to Dental Fluorosis
The CDC survey also found that fluorosis affects more black American children than white American children. According to the CDC, “No clear explanation exists why fluorosis was more severe among non-Hispanic black children than among non-Hispanic white or Mexican-American children. This observation has been reported elsewhere, and different hypotheses have been proposed, including biologic susceptibility or greater fluoride intake. ”20
Children Are Being Overexposed to Fluoride
These surveys of dental fluorosis indicate that today, even without fluoridation, a large number of children are overexposed to fluoride from an increasing number of sources. Opponents and proponents of fluoridation offer diametrically opposed responses to this problem.
The simplest and most direct way of improving this unacceptable situation, opponents say, is to end water fluoridation. Not only would that remove a major and direct source of fluoride, but it would also eliminate an indirect source—the cumulative amounts of fluoride ending up in beverages and foods processed in fluoridated communities.
Proponents argue instead that we should go after the discretionary sources of fluoride (sources of fluoride over which the individual has some control) by limiting or eliminating the use of fluoride supplements and putting more effort into educating parents to stop their children from swallowing fluoridated toothpaste. While laudable, the latter recommendation is somewhat ironic, because one of the reasons for introducing fluoridation in the first place was to reduce parental responsibility in these matters.
A Cosmetic Problem?
Proponents insist that dental fluorosis is merely a cosmetic problem, not a health problem. Until the condition becomes severe, they argue, fluorosis does not interfere with the functioning of the tooth or increase susceptibility to dental decay. What this position ignores are the psychological impacts children who suffer from mild, moderate, or severe dental fluorosis undoubtedly experience. In an article published in the New York State Dental Journal in 2008, Elvir Dincer, DDS, concluded that children’s self-esteem is harmed by even mild fluorosis. 21 As well, to claim that dental fluorosis is merely cosmetic is to ignore an indication of a systemic effect that has caused some alteration of the biochemistry of the growing tooth. 22
Opponents of fluoridation are concerned that dental fluorosis in a child may signal that damage to other tissues has also occurred. That damage may be less visible and less obvious but possibly far more serious.
Possible Mechanisms of Damage
While the exact mechanism by which fluoride damages the enamel is not yet known, three possibilities have been suggested:
1. Inhibition of enzymes (proteases that remove the last traces of protein between the crystals that make up enamel) in the growing teeth23–25
2. Interference with G protein-signaling mechanisms26
3. Interference with thyroid function27
There is no law that says interference in biochemistry will not occur in other tissues as it does in teeth. For fluoridation promoters, it has always been an article of faith that the presence of dental fluorosis does not signal any other damage to the human body. This we have called the Great Fluoridation Gamble, the subject we address in chapters 9 and 10.
Promoters’ Spin
Not surprisingly, promoters of fluoridation have always worried about how they could convince the public of the “safety” of fluoridation, while acknowledging the increase in dental fluorosis it causes. At a meeting of state dental directors held in Washington, D. C. , in 1951, Dr. Frank Bull, then dental director for the state of Wisconsin and an avid and very prominent early promoter of fluoridation, gave this advice on how to handle the dilemma:
What are some of the objections that are brought up on this fluoridation program? I think the first one that is brought up is: “Isn’t fluoride the thing that causes mottled enamel or fluorosis? Are you trying to sell us on the idea of putting that sort of thing in the water?”
What is your answer? You have got to have an answer, and it had better be good. You know, in all public health work it seems to be quite easy to take the negative. They have you on the defensive all the time, and you have to be ready with answers. Now, we tell them this, that at one part per million dental fluorosis brings about the most beautiful looking teeth that anyone ever had and we show them some pictures of such teeth. We don’t try to say that there is no such thing as fluorosis even at 1. 2 parts per million which we are recommending. But you have got to have an answer. Maybe you have a better one. 28
Over fifty years after Dr. Bull offered his advice to fluoridation promoters, Dr. Peter Cooney, chief dental officer of Canada, had this to say about mild dental fluorosis in a public hearing held in Thunder Bay, Ontario, on July 20, 2009:
Mild fluorosis shows teeth as being a very nice white color. It is called mild fluorosis because kids love it and adults love it. People will go to dentists to get bleaching so that they will look like this. What it does of course is to make the enamel of the teeth much harder so not only are kids happy with the color and the whiteness but it is also much more resistant to decay. 29
We suspect very few children or adults share Dr. Cooney’s enthusiasm for the appearance of mild dental fluorosis, which can affect up to 50 percent of the tooth surface (see photos at the Web site of the Fluoride Action Network, www.fluoridealert.org), especially when, with aging, the white patches slowly turn orange and brown.
Summary
The “optimal” fluoride concentration was originally defined as 1 ppm on the basis that that reduced caries but caused fluorosis in only about 10 percent of children and then only of the very mild type. Dean considered that even mild fluorosis was unacceptable aesthetically and indicative of systemic toxicity. More recent studies show that, by that criterion, many children in industrialized countries are receiving too much fluoride, even where the water is not artificially fluoridated. In fluoridated areas a substantial minority of children may have fluorosis of aesthetic concern (mild, moderate, or severe). Proponents of fluoridation admit only that this is a cosmetic problem that may call for expensive treatment. They are less ready to concede that it is in fact a manifestation of systemic fluoride poisoning.
•
12 •
Fluoride’s Chemistry,
Biochemistry, and Physiology
The standard approach used by toxicologists when assessing the potential toxicity of a substance is to investigate its properties in this sequence: its chemistry, biochemistry, and physiology; its impact on animals; and finally its impact on humans. Because of the limits on human experimentation, however, seldom do toxicologists enjoy the luxury of having numerous human studies at their fingertips. Fluoride is unusual in this respect, because millions of people worldwide have been exposed to high natural levels, with serious health consequences; these are discussed in chapters 13–19.
Chemistry
This is not the place to write a textbook on chemistry, but perhaps a brief lesson will be helpful.
Elements
Fluorine is one of approximately one hundred elements that make up our universe. Most of these elements are classified as metals (iron, copper, silver, sodium, etc. ), with only a dozen or so classified as nonmetals (carbon, nitrogen, oxygen, hydrogen, fluorine, chlorine, bromine, iodine, sulfur, phosphorus, silicon, arsenic, and the noble gases—helium, neon, argon, etc. ).
Fluorine forms chemical compounds with almost every other element. With sodium, for example, it forms sodium fluoride (NaF), and with calcium, calcium fluoride (CaF2).
Compounds
When elements combine chemically, the properties of the resulting compound are completely different from those of the parent elements. For example, when sodium (a very
reactive metal that has an almost explosive reaction with water) combines with chlorine (a poisonous gas used in World War I and used today to kill bacteria in water), the compound formed is sodium chloride, or the common table salt we are happy to sprinkle on our food!
There is a world of difference between the element fluorine and the fluoride compounds it forms when it combines with metals (e. g. , sodium fluoride, calcium fluoride), which in turn are different from the organofluorine compounds it forms with carbon (e. g. , perfluoroethylene), but commentators frequently confuse the element fluorine with the metallic fluorides and sometimes the organofluorine compounds. The key difference between the latter sets of compounds is that the former contain ions and the latter contain molecules (molecules are groups of atoms held together with strong linkages called covalent bonds).
Note 1: When a nonmetal element combines with another element, we change the ending of the nonmetal from ine to ide; for example, sodium and fluorine combine to form sodium fluoride.
Note 2: While there are only about one hundred elements, there are literally millions of compounds.
Fluorine
Fluorine—the element—is a pale yellow gas, and because it is so extremely reactive, it is never found as the free element in nature. What we find in nature are its compounds with other elements, such as calcium fluoride, which is found as the mineral fluorspar (CaF2). Another important mineral containing fluorine is cryolite (Na3AlF6). This latter mineral is of critical importance in the electrolytic process used to extract the metal aluminum from bauxite.
