13.  Does fluoride in the water supply, at the levels recommended for the prevention of tooth decay, adversely affect human health?

The overwhelming weight of scientific evidence indicates that fluoridation of community water supplies is both safe and effective.

For generations, millions of people have lived in areas where fluoride is found naturally in drinking water in concentrations as high or higher than those recommended to prevent tooth decay.  In August 1993, the National Research Council, a branch of the National Academy of Sciences, released a report prepared for the Environmental Protection Agency (EPA) which confirmed the currently allowed fluoride levels in drinking water do not pose a risk for health problems such as cancer, kidney failure or bone disease.
(National Research Council.  Health effects of ingested fluoride.  Report of the Subcommittee on Health Effects on Ingested Fluoride.  Washington, DC: National Academy Press;1993.)
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Many organizations in the U.S. and around the world involved with health issues have recognized the benefits of community water fluoridation.  The American Dental Association adopted its original resolution in support of fluoridation in 1950, and has repeatedly reaffirmed its position publicly and in its House of Delegates based on its continuing evaluation of the safety and effectiveness of fluoridation.
(American Dental Association, Survey Center, 1998 Consumers' opinions regarding community water fluoridation.  Chicago; June 1998.)

The American Medical Association's (AMA) House of Delegates first endorsed fluoridation in 1951. In 1986, and again in 1996, the AMA reaffirmed its support for fluoridation as an effective means of reducing dental decay. 
(American Medical Association. H-440.945 and H-440.972. In: American Medical Association Policy Compendium.  Chicago: American Medical Association;1998:633,637.)
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The World Health Organization, which initially recommended the practice of water fluoridation in 1969, reaffirmed its support for fluoridation in 1994 stating that: "Providing that a community has a piped water supply, water fluoridation is the most effective method of reaching the whole population, so that all social classes benefit without the need for active participation on the part of the individuals."
(World Health Organization.  Fluorides and oral health.  Report of a WHO Expert Committee on Oral Health Status and Fluoride Use.  WHO Technical Report Series 846. Geneva;1994.)

Following a comprehensive 1991 review and evaluation of the public health benefits and risks of  fluoride, the U.S. Public Health Service reaffirmed its support for fluoridation and continues to recommend the use of fluoride to prevent dental decay.

14. Are additional studies being conducted to determine the effects of fluorides in humans?

Yes. Since its inception, fluoridation has undergone a nearly continuous process of reevaluation. As with other areas of science, additional studies on the effect of fluorides in humans can provide insight as to how to make more effective choices for the use of fluoride. The American Dental Association and the U.S. Public Health Service support this on going research.

The accumulated dental, medical and public health evidence concerning fluoridation has been reviewed and evaluated numerous times by academicians, committees of experts, special councils of government and most of the world's major national and international health organizations.  The verdict of the scientific community is that water fluoridation, at the recommended levels, provides major oral health benefits. The question of possible secondary health effects caused by fluorides consumed in optimal concentrations throughout life has been the object of thorough medical investigations which have failed to show any impairment of general health.

 In scientific research, there is no such thing as "final knowledge".  New information is continuously emerging and being disseminated.  While research continues, the weight of scientific evidence indicates water fluoridation is safe and effective in preventing dental decay in humans.
(US Department of Health and Human Services, Public Health Service.  Review of fluoride: benefits and risks. Report of the Ad Hoc Subcommittee on Fluoride.  Washington, DC; February 1991.)
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15.  Does the total intake of fluoride from air, water and food pose significant health risks?

The total intake of fluoride from air, water and food in an optimally fluoridated community in the United States does not pose significant health risks.

Fluoride from the Air
The atmosphere normally contains negligible concentrations of airborne fluorides.  Studies reporting the levels of fluoride in air in the United States suggest that ambient fluoride contributes little to an individual's overall fluoride intake. 
(Hodge HC, Smith FA. Occupational fluoride exposure.  J Occup Med 1977,19:12-39;  Committee on Biologic Effects on Atmospheric Pollutants.  Biological effects of atmospheric pollutants: fluorides.  Washington, DC, National Academy of Sciences 1971:5-9.)

Fluoride from the Water  top of page |
When considering water fluoridation, an individual must consume one liter of water fluoridated at one part per million (1 ppm) to receive one milligram (1 mg) of fluoride.  Children under six years of age, on average, consume less than one-half liter of drinking water a day. Therefore, children under six years of age would consume, on average, less than 0.5 mg of fluoride a day from drinking optimally fluoridated water (at 1 ppm).
(Rugg-Gunn AJ. Nutrition and dental health. New York: Oxford University Press;1993.)

Fluoride in the Food
Fish, such as sardines, may contribute to higher dietary fluoride intake if the bones are ingested.  Brewed teas may also contain fluoride concentrations of one ppm to six ppm depending on the amount of dry tea used, the water fluoridation concentration and the brewing time.
(Whitford GM.  The metabolism and toxicity of fluoride, 2^nd rev. ed.  Monographs in oral science, Vol. 16.  Basel, Switzerland: Karger;1996.)
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Questions concerning the possible concentration of fluoride through the biologic food chain have been addressed by the National Academy of Sciences, which concluded:

Indeed, domestic animals can serve as a protective barrier for humans. Approximately 99% of the fluoride retained in the body is stored in bone, and only slight increases in the concentration of soft tissue fluoride occur even at high levels of dietary fluoride intake. There is, therefore, little danger to humans from the consumption of meat or milk from domestic animals even if the animals have ingested excessive fluoride. A few meat and fish products prepared for human consumption contain portions of comminuted (crushed) bone that may contribute to a higher fluoride content.  The proportion of the total diet represented by these products, however, would generally be very small indeed.

16.  How much fluoride should an individual consume each day to reduce the occurrence of dental decay?

The appropriate amount of daily fluoride intake varies with age and body weight. As with other nutrients, fluoride is safe and effective when used and consumed properly.

*Values based on data collected during 1988-94 as part of the Third National Health and Nutrition Examination Survey (NHANES III) in the United States.
(Institute of Medicine, Food and Nutrition Board.  Dietary reference intakes for calcium, phosphorous, magnesium, vitamin D and fluoride.  Report of the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes.  Washington, DC:National Academy Press;(In press).)
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Decay rates are declining in many population groups because children today are being exposed to fluoride from a wider variety of sources than decades ago.  Many of these sources are intended for topical use only; however, some fluoride is inadvertently ingested by children.
(Levy SM, Maurice TJ, Jakobsen JR. Feeding patterns, water sources and fluoride exposures of infants and one -year-olds. J Am Dent Assoc 1993;124:65-9.) 

For example, it has been reported in a number of studies that young children inappropriately swallow an average of 0.30 mg of fluoride from fluoride toothpaste at each brushing.  Although toothpaste is not meant to be swallowed, children may consume the daily recommended adequate intake amount of fluoride from toothpaste alone. In order to decrease the risk of dental fluorosis, the American Dental Association has since 1992 recommended that parents and care givers put only one pea-sized amount of fluoride toothpaste on a young child's toothbrush at each brushing.  Also, young children should be supervised while brushing and taught to spit out, rather than swallow, the toothpaste.

17. When fluoride is ingested, where does it go?

Much is excreted; almost all of the fluoride retained in the body is found in calcified (hard) tissues, such as bone and teeth.  Fluoride helps to prevent dental decay when incorporated into the teeth.

After ingestion of fluoride, such as drinking a glass of optimally fluoridated water, the majority of the fluoride is absorbed from the stomach and small intestine into the blood stream.
(Whiteford GM. The physiological and toxicological characteristics of fluoride. J Dent Res 1990;69 (Spec Iss):539-49.)
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Approximately 50% of the fluoride absorbed each day by young or middle-aged adults become associated with hard tissues within 24 hours while virtually all of the remainder is excreted in the urine.

Ingested or systemic fluoride becomes incorporated into forming tooth structures.  Fluoride ingested regularly during the time when teeth are developing is deposited throughout the entire surface of the tooth and contributes to long-lasting protection against dental decay. (Newbrun E. Fluorides and dental caries, 3^rd ed. Springfield, Illinois: Charles C. Thomas, publisher; 1986.)

An individual's age and stage of skeletal development will affect the rate of fluoride retention.  The amount of fluoride taken up by bone and retained in the body is inversely related to age.  More fluoride is retained in young bones than in the bones of older adults.  The kidneys play the major role in the removal of fluoride from the body.  Normally kidneys are very efficient and excrete fluoride very rapidly.

18. Will the ingestion of optimally fluoridated water over a lifetime adversely affect bone health?

According to generally accepted scientific knowledge, the ingestion of optimally fluoridated water does not have an adverse effect on bone health.

The second major area of study regarding fluoride and bone health is the role of fluoride in strengthening bone and preventing fractures. For nearly 30 years, fluoride, primarily in the form of slow-release sodium fluoride, has been used as an experimental therapy to treat osteoporosis, a condition characterized by a reduction in the amount of bone mass.  Sodium fluoride therapy has been used in individuals in an effort to reduce further bone loss, or add to existing bone mass and prevent further fractures.
(Gordon SL, Corbin SB. Summary of workshops on drinking water fluoridation influence on hip fracture on bone health.  Osteoporosis Int 1992;2:109-17.)
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Lastly, the possible association between fluoride and bone cancer has been studied. Two studies were conducted to evaluate the carcinogenicity of sodium fluoride in laboratory animals. The ad hoc subcommittee on fluoride of the U.S. Public Health Service combined the results of the two studies and stated: "Taken together, the two animal studies available at this time fail to establish an association between fluoride and cancer".
(US Department of Health and Human Services, Public Health Service.  Review of the fluoride: benefits and risks. Report of the Ad Hoc Subcommittee on Fluoride.  Washington, DC; February 1991.)

19. What is dental fluorosis?

Dental fluorosis is a change in the appearance of teeth and is caused when higher than optimal amounts of fluoride are ingested in early childhood while tooth enamel is forming.  The risk of dental fluorosis can be greatly reduced by closely monitoring the proper use of fluoride products by young children.

Dental fluorosis is caused by a disruption in enamel formation which occurs during tooth development in early childhood.
(Whiteford GM. The metabolism and toxicity of fluoride, 2^nd rev. ed.  Monographs in oral science, Vol. 16.  Basel, Switzerland: Karger;1996.)
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Enamel formation of permanent teeth, other than third molars (wisdom teeth), occurs from about the time of birth until approximately five years of age. After tooth enamel is completely formed, dental fluorosis cannot develop even if excessive fluoride is ingested. 
(Horowitz HS.  Indexes for measuring dental fluorosis. J Public Health Dentistry 1986;46(4):179-183.)

Older children and adults are not at risk for dental fluorosis.  Dental fluorosis only becomes apparent when the teeth erupt.  Because dental fluorosis occurs while teeth are forming under the gums, teeth that have erupted are not at risk for dental fluorosis.

Dental fluorosis has been classified in a number of ways.  One of the most universally accepted classifications was developed by H. T. Dean in 1942:

In assessing the risks in regards to dental fluorosis, scientific evidence shows it is probable that approximately 10% of children consuming optimally fluoridated water, in the absence of fluoride from all other sources, will develop very mild dental fluorosis.
(Dean HT.  Chronic endemic dental fluorosis. JAMA 1936;107(16):1269-73.)

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The risk of teeth forming with the very mildest form of fluorosis must be weighed against the benefit that the individual's teeth will also have a lower rate of dental decay thus saving dental treatment costs.

The type of fluorosis seen today remains largely limited to the very mild and mild categories, although the prevalence of enamel fluorosis in both fluoridated and nonfluoridated communities in the United States is higher than it was when original epidemiological studies were done approximately 60 years ago.  Because fluoride intake from water and the diet appears not to have increased since that time, the additional intake by children at risk for dental fluorosis is believed to be caused by consumer's inappropriate use of fluoride-containing dental products. As the ADA has recommended, the risk of fluorosis can be greatly reduced by following label directions for the use of these fluoride products.
(Institute of Medicine, Food and Nutrition Board.  Dietary reference intakes for calcium, phosphorous, magnesium, vitamin D and fluoride.  Report of the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes.  Washington, DC: National Academy Press;(In press);  Leone NC, Shimkin MB, Arnold FA, et al. Medical aspects of excessive fluoride in a water supply. Public Health Rep 1954;69(10):925-36.).

20.  Can fluorosis in children's teeth be prevented?

Because risk factors have been identified and verified by generally accepted scientific knowledge, the occurrence of dental fluorosis in the United States can be reduced without denying young children the decay prevention benefits of community water fluoridation.

Studies have established a direct relationship between young children brushing with more than the recommended pea-sized amount of fluoride toothpaste and the risk of very mild or mild dental fluorosis. (Levy SM. A review of fluoride intake from fluoride dentifrice.  J Dent Child 1993;60(2):115-24;   Stookey GK. Review of fluorosis risk of self-applied topical fluorides: dentifrices, mouth rinses and gels.  Community Dent Oral Epidemiol 1994;22(3):181-6;   Pendrys DG, Katz RV, Morse DE.  Risk factors for enamel fluorosis in a nonfluoridated population. Am J Epidemiol 1996;143(8):808-15.)

Fluoride supplements should only be prescribed for children living in nonfluoridated areas.  Parents, care givers and health care professionals should judiciously monitor use of all fluoride-containing dental products by children under age six.  As is the case with any therapeutic product, more is not always better. Care should be taken to adhere to label directions on fluoride prescriptions and over-the-counter products (e.g. fluoride toothpastes and rinses). The American Dental Association recommends the use of fluoride mouth rinses, but not for children under six years of age because they may swallow the rinse.

In homes where young children are consuming water with a fluoride level greater than two ppm, families should use an alternative primary water source, such as bottled water, for drinking and cooking. Private wells should be tested at least yearly due to possible fluctuations in water tables. It is important to remember that the American Dental Association recommends dietary fluoride supplements only for children living in areas with less than optimally fluoridated water.
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21.  Is fluoride, as provided by community water fluoridation, a toxic substance?

Fluoride, at the concentrations found in optimally fluoridated water, is not toxic according to generally accepted scientific knowledge.

Like many common substances essential to life and good health - salt, iron, vitamins A and D, chlorine, oxygen and even water itself - fluoride can be toxic in excessive quantities.  The amount of fluoride necessary to cause death for a human adult (155 pound man) has been estimated to be five - ten grams of sodium fluoride, ingested at one time.
(Hodge HC, Smith FA. Biological properties of inorganic fluorides.  In: Fluorine chemistry. Simons HH, ed. New York: Academy Press;1965:1-42.) 

This is more than 10,000-20,000 times as much fluoride as is consumed at one time in a single eight -ounce glass of optimally fluoridated water.

As with other nutrients, fluoride is safe and effective when used and consumed properly. While large doses of fluoride may be toxic, it is important to recognize the difference in the effect of a massive dose of an extremely high level of fluoride versus the recommended amount of fluoride found in optimally fluoridated water.  Many substances in widespread use are very beneficial in small amounts, but may be harmful in large doses - such as salt, chlorine and even water itself.

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22.  Does drinking optimally fluoridated water cause or accelerate the growth of cancer?

According to generally accepted scientific knowledge, there is no connection between cancer rates in humans and adding fluoride to drinking water. 
(American Cancer Society.  A statement on fluoride and drinking water fluoridation by Clark W. Heath, Jr. MD, Vice President of Epidemiology and Surveillance Research of American Cancer Society;February 17, 1998.)

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.
(US Department of Health and Human Services, Public Health Service.  Review of fluoride: benefits and risks.   Report of the Ad Hoc Subcommittee on Fluoride. Washington, DC; February 1991.)

Despite the abundance of scientific evidence, claims of a link between fluoridation and increased cancer rates continue. This assertion is based on one study comparing cancer death rates in ten large fluoridated cities versus ten large nonfluoridated cities in the United States.  The results of this study have been refuted by a number of organizations and researchers.
(Clemmesen J. The alleged association between artificial fluoridation of water supplies and cancer: a review.  Bulletin of the World Health Organization 1983;61(5):871-83.)
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The National Cancer Institute analyzed the same data and found that the original investigators failed to adjust their findings for variables, such as age and gender differences, which affect cancer rates. Following further reviews of the study, the consensus of the scientific community continues to support the conclusion that the incidence of cancer is unrelated to the introduction and duration of water fluoridation.
(US Department of Health and Human Services, Public Health Service.  Review of fluoride: benefits and risks. Report of the Ad Hoc subcommittee on Fluoride. Washington, DC; February 1991.)

In a document entitled "Fluoride and Drinking Water Fluoridation", the American Cancer Society states, "Scientific studies show no connection between cancer rates in humans and adding fluoride to drinking water".
(American Cancer Society.  A statement on fluoride and drinking water fluoridation by Clark W. Heath, JR. MD, Vice President of Epidemiology and Surveillance Research of American Cancer Society; February 17, 1998.)

23.  Does fluoride, as provided by community water fluoridation, inhibit the activity of enzymes in humans?

Fluoride, in the amount provided through optimally fluoridated water, has no effect on human enzyme activity according to generally accepted scientific knowledge.

Enzymes are organic compounds which promote chemical change in the body.  Generally accepted scientific knowledge has not indicated that optimally fluoridated water has any influence on human enzyme activity.

The two primary physiological mechanisms that maintain a low concentration of fluoride ions in body fluids are the rapid excretion of fluoride by the kidneys and the uptake of fluoride by calcified tissues. | Next Set of Questions | Back to Fluoridation | top of page |

24.  Can fluoride, as found in optimally fluoridated drinking water, alter immune function or produce allergic reaction (hypersensitivity)?

According to generally accepted scientific knowledge, there is no evidence of any adverse effect on specific immunity from fluoridation, nor have there been any confirmed reports of allergic reaction.
(Challacombe SJ. Does fluoridation harm immune function?  Comm Dent Health 1996;13(Suppl 2):69-71.)

A 1996 review of the literature on fluoride and white cell function examined numerous studies and concluded that there is no evidence of any harmful effect on specific immunity following fluoridation nor any confirmed reports of allergic reactions. 
(Challacombe SJ. Does fluoridation harm immune function?  Comm Dent Health 1996;13(Suppl 2):69-71.)

25. Does drinking optimally fluoridated water cause AIDS?

There is no scientific evidence linking the consumption of optimally fluoridated water and AIDS (acquired immune deficiency syndrome).

AIDS is caused by a retro virus known as the human immunodeficiency virus (HIV). The routes of transmission of HIV include unprotected sexual activity, exposure to contaminated blood or blood products and as a result of an infected woman passing the virus to the fetus during pregnancy or to the newborn at birth.
(American Dental Association, American Academy of Oral Medicine. Dental management of the HIV-infected patient. J Am Dental Assoc 1995;126(Suppl):8.)

There is no scientific evidence linking HIV or AIDS with community water fluoridation. (US Department of Health and Human Services, Centers for Disease Control, Dental Disease Prevention Activity.  Update of fluoride/acquired immunodeficiency syndrome (AIDS) allegation. Pub. No. FL-133. Atlanta; June 1987.) 
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26.  Is fluoride, as provided by community water fluoridation, a genetic hazard?

Following a review of generally accepted scientific knowledge, the National Research Council of the National Academy of Sciences supports the conclusion that drinking optimally fluoridated water is not a genetic hazard. 
(National Research Council.  Health effects of ingested fluoride.  Report of the Subcommittee on Health Effect of Ingested Fluoride. Washington, DC: National Academy Press;1993.)

Chromosomes are the DNA-containing bodies of cells which are responsible for the determination and transmission of hereditary characteristics.  Genes are the functional hereditary unit that occupy a fixed location on a chromosome.  Many studies have examined the possible effects of fluoride on chromosome damage. While there are no published studies on the genotoxic (damage to DNA) effect of fluoride in humans, numerous studies have been done on mice.
(National Research Council.  Health effects of ingested fluoride.  Report of the Subcommittee on Health Effects of Ingested Fluoride.  Washington, DC: National Academy Press;1993.)   | Next Set of Questions | Back to Fluoridation | top of page |

These studies have shown no evidence that fluoride damages chromosomes in bone marrow or sperm cells even at fluoride levels 100 times higher than that in fluoridated water.

The lowest dose of fluoride reported to cause chromosomal changes in mammalian cells was approximately 170 times that found normally in human cells in areas where drinking water is fluoridated, which indicates a very large margin of safety.
(National Research Council.  Health effects of ingested fluoride.  Report of the Subcommittee on Health Effects of Ingested Fluoride.  Washington, DC: National Academy Press;1993.) 

27.  Does drinking optimally fluoridated water cause an increase in the rate of children born with Downs Syndrome?

There is no generally accepted scientific knowledge establishing a relationship between Downs Syndrome and the consumption of optimally fluoridated drinking water.

This question originally arose because of two studies published in 1956 and 1963.  Data collected in several midwest states in 1956 formed the basis for two articles published in french journals, purporting to prove a relationship between fluoride in the water and Downs Syndrome.
(Rapaport I Contribution a l'etude de mongolisme: role pathogenique de fluor.  Bull Acad M (Paris) 1953;140:529-31;  Rapaport I Oligophrenic mongolienne et caries dentairs.  Rev Stomatol Chir Maxillofac 1963;46:207-18.)
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Experienced epidemiologists and dental researchers from the National Institute of Dental Research and staff members of the National Institute of Mental Health have found serious shortcomings in the statistical procedures and designs of these two studies. Among the most serious inadequacies is the fact that conclusions were based on the fluoridation status of the communities where the mothers gave birth, rather than the status of the rural area where many of the women lived during their pregnancies.  
(Hodge HC, Smith FA. Biological properties of inorganic fluorides: In: Fluorine chemistry.  Simons HH, ed. New York: Academic Press;1965:1-42.)

A comprehensive study of Downs Syndrome births was conducted in 44 U.S. cities over a two-year period.  Rates of Downs Syndrome were comparable in both fluoridated and nonfluoridated cities.
Erickson JD. Down syndrome, water fluoridation and maternal age.  Teratol 1980;21:177-80.)
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28.  Does ingestion of optimally fluoridated water have any neurological impact?

There is no generally accepted scientific knowledge establishing a casual relationship between consumption of optimally fluoridated water and central nervous system disorders, including effects on intelligence.

A seven-year study compared the health and behavior of children from birth through six years of age in communities with optimally fluoridated water with those of children the same age without exposure to optimally fluoridated water. Medical records were reviewed yearly during the study. At age six and seven, child behavior was measured using both maternal and teacher ratings. The results suggested that there was no evidence to indicate that exposure to optimally fluoridated water had any detectable adverse effect on children's health or behavior.  These results did not differ even when data was controlled for family social background.
(Shannon FT, Fergusson DM, Horwood LF. Exposure to fluoridated public water supplies and child health and behaviour.  N Z Med J 1986;99(803):416-8.)

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29. Does drinking optimally fluoridated water cause Alzheimer's disease?

Generally accepted science has not demonstrated an association between drinking optimally fluoridated water and Alzheimer's Disease.

The exact cause of Alzheimer's Disease (AD) has yet to be identified.  Scientists have identified the major risk factors for AD as age and family history.  Other possible risk factors include a serious head injury and lower levels of education.  Scientists are also studying additional factors to see if they may be associated with the disease.  These include genetic (inherited) factors, virus, and environmental factors such as aluminum, zinc, and other metals. Researchers have found these metals in the brain tissue of people with AD, but it is not known if these metals cause AD or build up in the brain as a result of the disease.
(National Institute on Aging.  Alzheimer's Disease fact sheet. NIH Publication No. 95-3431;August 1995.)

Because aluminum has been found in the brain tissue of people with AD, claims have been made that fluoridated water "leaches" out the aluminum in cookware when used for boiling water, thereby implicating fluoride as a cofactor in the development of AD. One experiment attempted to test this claim by measuring the release of aluminum from aluminum cookware under the most adverse conditions, with and without the presence of fluoride.  Throughout these trials, scientists were unable to leach out significant amounts of aluminum from any of the cookware, including those that were exposed to extreme acidic or alkaline conditions.
(US Department of Health and Human Services, Centers for Disease Control, Dental Disease Prevention Activity.  No association between aluminum, fluoride and Alzheimer's Disease.  Pub. No FL-132. Atlanta;May 1987.) 
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Interestingly, there is evidence that aluminum and fluoride are mutually antagonistic in competing for absorption in the human body.  (Kraus AS, Forbes WF. Aluminum, fluoride, and the prevention of Alzheimer's Disease.
(Can J Public Health 1992;83(2):97-100.) 

While a conclusion cannot be made that consumption of fluoridated water has a preventive effect on AD, there is no generally accepted scientific knowledge to show consumption of optimally fluoridated water is a risk factor for AD.

30.  Does drinking optimally fluoridated water cause or contribute to heart disease?

Broad national experience and generally accepted scientific knowledge demonstrate that drinking optimally fluoridated water is not a risk factor for cardiovascular disease.

The American Heart Association has reaffirmed its historical position that heart disease is not related to the amount of fluoride present in drinking water.
(Mary Wintons, Ed.D., personal communication, July 20, 1993.) 

The American Heart Association identifies cigarette and tobacco smoke, high blood cholesterol levels, high blood pressure, physical inactivity and obesity as major risk factors for cardiovascular disease.
(American Heart Association.  Risk factors and coronary heart disease. Available at http://www.americanheart.org/Heart_and_Stroke_A_Z_Guide /riskfact.html>. Accessed June 27, 1998.)

No evidence was found of any harmful health effects, including heart disease, attributable to fluoridation.  As in other studies, crude differences in the mortality experience of the cities with fluoridated and nonfluoridated water supplies were explainable by differences in age, gender and race composition. 
(Erickson JD.  Mortality in selected cities with fluoridated and non-fluoridated water supplies. New Eng J Med 1978;298(2):1112-6.)   | Next Set of Questions | Back to Fluoridation | top of page |

31. Is the consumption of optimally fluoridated water harmful to kidneys?

Generally accepted scientific knowledge suggests that the consumption of optimally fluoridated water does not cause or worsen human kidney disease.

In a report issued in 1993 by the National Research Council, the Subcommittee on Health Effects of Ingested Fluoride stated that the threshold dose of fluoride in drinking water which causes kidney effects in animals is approximately 50 ppm - more than 12 times the maximum level allowed in drinking water by the Environmental Protection Agency.  Therefore, they concluded that "ingestion of fluoride at currently recommended concentrations is not likely to produce kidney toxicity in humans."
(National Research Council.  Health effects of ingested fluoride.  Report of the Subcommittee on Health Effects of Ingested Fluoride.  Washington, DC:National Academy Press;1993.)
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Many people with kidney failure depend on hemodialysis (treatment with an artificial kidney machine) for their existence.  During hemodialysis, the patient's blood is exposed to large amounts of water each week (280-560 quarts).  Therefore, procedures have been designed to ensure that the water utilized in the process contain a minimum of dissolved substances that could diffuse indiscriminately into the patient's bloodstream.
(US Department of Health and Human Services, Public Health Service.  Surgeon General's advisory: treatment of water for use in dialysis: artificial kidney treatments. Washington, DC: Government Printing Office 872-021;June 1980.)

32.  Will the addition of fluoride affect the quality of drinking water?

There is no scientific evidence that optimal levels of fluoride affect the quality of water. All ground and surface water in the United States contains some naturally occurring fluoride.

Nearly all water supplies must undergo various water treatment processes to be safe and suitable for human consumption.  The substances used for this purpose include aluminum sulfate, ferric chloride, ferric sulfate, activated carbon, lime, soda ash, and, of course, chlorine.  Fluoride is added only to water that has naturally occurring lower than optimal levels of this mineral.
 (US Department of Health and Human Services, Centers for Disease Control, Dental Disease Prevention Activity.  Water fluoridation: a manual for engineers and technicians. Atlanta; September 1986.)
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Under the Safe Drinking Water Act, the EPA has established drinking water standards for a number of substances, including fluoride, in order to protect the public's health. In a notice of a final rule relating to fluoride compounds the EPA stated, "There exists no directly applicable scientific documentation of adverse medical effects at levels of fluoride below 8 mg/L (0.23 mg/kg/day)". The EPA's Maximum Concentration Limit (MCL) of 4.0 mg/L (0.114 mg/kg/day) is one half that amount, providing an adequate margin of safety.

33.  Does fluoridation present difficult engineering problems?

No.  Properly maintained and monitored water fluoridation systems do not present difficult engineering problems.

With proper planning and maintenance of the system, fluoride adjustment is compatible with other water treatment processes.  Today's equipment allows water treatment personnel to easily monitor and maintain the desired fluoride concentration. 

There are only three basic compounds used to fluoridate community drinking water: 1) sodium fluoride, a white, odorless crystalline material; 2) sodium fluorosilicate, a white or yellow-white, odorless crystalline powder; and 3) fluorosilicic acid, a white to straw-colored liquid. The three fluoride compounds are derived from the mineral apatite which is a mixture of calcium compounds.

Fluoride compounds are added to the water supply as liquids, but are measured by two basic types of devices, dry feeders or solution feeders (metering pumps). By design, and with proper maintenance and testing, water systems limit the amount of fluoride that can be added to the system (i.e., the use of a day tank that only holds one day's supply of fluoride) so prolonged over-fluoridation becomes a mechanical impossibility.
 (US Department of Health and Human Services, Centers for Disease Control, Dental Disease Prevention Activity. Water fluoridation: a manual for engineers and technicians. Atlanta; September 1986.)
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Allegations that fluoridation causes corrosion of water delivery systems are not supportable.  Corrosion by drinking water is related primarily to dissolved oxygen concentration, pH, water temperature, alkalinity, hardness, salt concentration, hydrogen sulfide content and the presence of certain bacteria.  Under some water quality conditions, a small increase in the corrosivity of drinking water that is already corrosive may be observed after treatment with alum, chlorine, fluorosilicic acid or sodium florosilicate. In such cases, further water treatment is indicated to adjust the pH upward. This is part of routine water plant operations.