How do I know fluoridated water is safe?
Over 50 years of research and experience have shown that fluoridation at optimal levels does not harm people or the environment. Leading scientists and health professionals, numerous professional organizations, and governments around the world support community water fluoridation.
A report of the Ad Hoc Subcommittee on Fluoride of the Committee to Coordinate Environmental
Health and Related Programs, United States Public Health Services (February 1991) provided sound scientific conclusions about fluoride.
Extensive studies over the past 50 years have established that individuals whose drinking water is fluoridated show a reduction in dental caries. Although the comparative degree of measurable benefit has been reduced recently as other fluoride sources have become available in non-fluoridated areas, the benefits of water fluoridation are still clearly evident. Fewer caries are associated with fewer abscesses and extractions of teeth and with improved health. The health and economic benefits of water fluoridation accrue to individuals of all ages and socioeconomic groups, especially to poor children.
Since the addition of fluoride to drinking water in the 1940's, other sources of fluoride have become available, including toothpastes, mouth rinses, and fluoride dietary supplements. These sources of fluoride also have proven to be effective in preventing dental caries.
Optimal fluoridation of drinking water does not pose a detectable cancer risk to humans as evidenced by extensive human epidemiological data available to date, including the new studies prepared for this report. While the presence of fluoride in sources other than drinking water reduces the ability to discriminate between exposure in fluoridated as compared to non-fluoridated communizes, no trends in cancer risk, including the risk of osteosarcoma, were attributed to the introduction of fluoride into drinking water in these new studies. During two time periods, 1973-1980 and 1981-1987, there was an unexplained increase of osteosarcoma in males under age 20. The reason for this increase remains to be clarified, but an extensive analysis reveals that it is unrelated to the introduction and duration of fluoridation.
There are two methodologically acceptable studies of the carcinogenicity of fluoride in experimental animals. The Procter and Gamble study did not find any significant evidence of carcinogenicity in rats and mice of either sex. In the NTP study there was no evidence of carcinogenicity in mice and in female rats. Male rats showed "equivocal" evidence of carcinogenicity based on the finding of a small number of osteosarcomas. "Equivocal" evidence is defined by NTP as "...interpreted as showing a marginal increase in neoplasms that may be chemically related" (HHS, 1990). Taken together, the data available at this time from these two animal studies fail to establish an association between fluoride and cancer.
By comparison with the 1940's, the total prevalence of dental fluorosis has increased in non-fluoridated areas and may have increased in optimally fluoridated areas. Such increases in dental fluorosis in a population signify that total fluoride exposures have increased and may be more than are necessary to prevent dental caries. For this reason, prudent public health practice dictates the reduction of unnecessary and inappropriate fluoride exposure.
In the 1940s, drinking water and food were the major sources of fluoride exposure. Since then, additional sources of fluoride have become available through the introduction of fluoride containing dental products. Although the use of these products is likely responsible for some of the declines in caries scores, the inappropriate use of these products has also likely contributed to the observed increases in the prevalence of very mild and mild forms of dental fluorosis.
Further epidemiological studies are required to determine whether or not an association exists between various levels of fluoride in drinking water and bone fractures.
Crippling skeletal fluorosis is not a public health problem in the United States, as evidenced by the reports of only five cases in 30 years. Crippling skeletal fluorosis, a chronic bone and joint disease associated with extended exposure to high levels of fluoride, has been more prevalent in some regions outside the United States.
Well-controlled studies have not demonstrated a beneficial effect of the use of high doses of fluoride in reducing osteoporosis and related bone fractures.
Genotoxicity studies of fluoride, which are highly dependent on the methods used, often show contradictory findings. The most consistent finding is that fluoride has not been shown to be mutagenic in standard tests in bacteria (Ames Test). In some studies with different methodologies, fluoride has been reported to induce mutations and chromosome aberrations in cultured rodent and human cells. The genotoxicity of fluoride in humans and animals is unresolved despite numerous studies.
Chronic low level fluoride exposure is nor associated with birth defects. Studies also fail to establish an association between fluoride and Down Syndrome.
There is no indication that chronic low level fluoride exposure of normal individuals presents a problem in other organ systems, such as the gastrointestinal, the genitourinary, and the respiratory systems. The effects of fluoride on the reproductive system merit further investigation in animal and human studies.
What are the adverse effects of fluoride?
Scientific literature does not support the claims that fluoride adversely affects the immune system, collagen, glucose metabolism, the integrity of genetic material, causes, attention deficit disorder, Alzheimer's disease, osteoporosis, cancer or AIDS, aggravates kidney disease or hypothyroidism. Anti-fluoridationists and anti-fluoride websites cite "scientific articles", most of which have methodological problems:
They are not from reputable peer-reviewed journals and are not obtainable through a medical or dental library
They do not deal with the fluoride compounds that are actually used to fluoridate water
They study exposure levels way above that possible at 1 ppm dilution of fluoridated water
They inappropriately try to extrapolate data from poorly designed animal or bench-top research with no relationship to the levels of fluoride in drinking water
Severe cosmetic or dentally injurious fluorosis of teeth or skeletal fluorosis is seen in some people growing up in areas with natural fluorides in 8 to 20 times the concentration as Arcata water. This leaves a wide safety margin for individual consumption.
Legitimate epidemiological studies have not detected health risks to water fluoridation at 1 ppm.
Since community water fluoridation was introduced in 1945, more than 50 epidemiologic studies in different populations and at different times have failed to demonstrate an association between fluoridation and the risk of cancer. Mild dental fluorosis (mottling of tooth enamel) can occur, particularly if a child also uses fluoridated toothpaste, but fluorosis does not weaken teeth. Skeletal fluorosis, which is a serious health problem, does not occur from drinking water, but can be an occupational and environmental health risk in the proximity of industries that utilize large amounts of fluoride. In contrast, the benefits of water fluoridation are great and easy to detect.
A very thorough survey of many US adults (using xrays and clinical diagnoses) found virtually no skeletal fluorosis in a population exposed for many years to natural fluoride in local water at 20 ppm (which is 20 times the recommended concentration). By comparison, in other countries there is fairly common skeletal fluorosis at concentrations half of that (but still 10 times more than in fluoridated drinking water). Clearly other factors must be operative.
Is fluoride REALLY safe?
Of course it is! Fluoride has been extensively studied for many years and it is right that it is constantly being re-evaluated so we have current data and analyses. Consistently, researchers from numerous different disciplines (physiology, toxicology, medicine, dentistry, public health, nutrition) have lines of evidence and analysis that all come to the same conclusionsfluoride is safe, effective, and cost effective.
|"Water fluoridation in low fluoride-containing water supplies helps to maintain optimal dental tissue development and dental enamel resistance against caries attack during the entire life span. People of all ages, including the elderly, benefit from community water fluoridation." -World Health Organization