Drinking Water: Fluoride

Fluoride in Drinking Water

Fluoride, a naturally occurring element, exists in combination with other elements as a fluoride compound and is found as a constituent of minerals in rocks and soil. When water passes through and over the soil and rock formations containing fluoride it dissolves these compounds, resulting in the small amounts of soluble fluoride present in virtually all water sources.

In some communities, fluoride is added to public water supplies; a process known as fluoridation. Water fluoridation involves adjusting the natural level of fluoride to the levels recommended to prevent tooth decay. There is no difference in potential health effects between naturally occurring fluoride or that added through fluoridation.

Fluoridation of drinking water can be controversial. Opponents argue fluoridation violates individual rights and goes against religious beliefs that ban medication. The courts have established fluoridation is not an unconstitutional invasion of religious freedom or other individual rights guaranteed by the First, Fifth or Fourteenth Amendments to the U.S. Constitution. It has been the position of courts that a significant government interest in health and welfare of the public generally overrides individual objections to public health regulation.

Opponents also argue that drinking fluoridated water promotes a variety of physical and mental ailments including sickle-cell anemia, cancer, cardiovascular disease, AIDS, Down Syndrome and Alzheimer's disease. Since the 1930's, many scientific studies have shown that water fluoridation, at the concentrations recommended for good oral health, has no harmful effects. A 1992 policy statement on water fluoridation by the Surgeon General of the U.S. Public Health Service and the Assistant Secretary of Health recommended fluoridation of community water supplies be continued in areas where naturally occurring fluoride levels are deficient.

Fluoridation is endorsed by both the American Dental Association and the American Medical Association, as well as numerous national and international organizations including the American Academy of Pediatrics, American Academy of Pediatric Dentistry, American Pharmaceutical Association, American Society of Dentistry for Children, Mayo Clinic, National Academy of Sciences, National Cancer Institute, National Health Council and U.S. Public Health Service Centers for Disease Control and Prevention, Food and Drug Administration and National Institute of Health.

Indications of Fluoride

Fluoride in drinking water cannot be detected by taste, sight or smell. Testing is the only way to determine the fluoride concentration.

Potential Health Effects

The dental benefits from consuming water containing optimum levels of fluoride are well-documented. The Nebraska Health and Human Services System Division of Dental Health indicates that 0.7 to 1.5 milligrams per liter of fluoride in drinking water protects against tooth decay, reducing the incidence of dental caries (tooth decay), as well as aiding bone and tooth development. The American Dental Association has stated that fluoride benefits people of all ages. When children are young and their teeth are still forming, fluoride makes tooth enamel harder and more resistant to decay-causing acid. Studies indicate that people who drink optimally fluoridated water from birth will experience up to 40 percent less decay over their lifetimes. For adults, fluoride helps repair the early stages of tooth decay even before it becomes visible, a process known as remineralization. For older adults, fluoride has been effective in decreasing problems with root caries (decay along the gumline).

Although low levels of fluoride are beneficial, excessive amounts can be harmful. Excessive fluoride in drinking water may produce fluorosis (mottling of teeth), which increases as the optimum level of fluoride is exceeded. Dental fluorosis appears during tooth formation and is caused by excessive fluoride ingestion, which leads to enamel protein retention, hypomineralization of the dental enamel and dentin and disruption of crystal formation. The effects range from barely perceptible white striations or specks on teeth to severe pitting and/or permanent brown to brownish gray stains on teeth. Continued consumption of water containing more than 2 mg/l fluoride will likely produce mild to moderate dental fluorosis. Continued consumption of water containing increasingly higher concentrations of fluoride will generally produce more severe dental fluorosis. However, according to the American Academy of Pediatrics, the effect of fluorosis is only cosmetic. Teeth affected by fluorosis seem to be resistant to dental caries.

Like other trace elements, excessive quantities of fluoride can result in acute or chroni