caries development. At this time, therefore, the use of balance data to estimate an adequate intake of fluoride is not warranted.
Because data are not available to determine an Estimated Average Requirement (EAR), the reference value that will be used for fluoride is the AI. The AI is based on estimated intakes that have been shown to reduce the occurrence of dental caries maximally in a population without causing unwanted side effects including moderate dental fluorosis.
The cariostatic effect associated with residence in communities served with optimally fluoridated water (ca. 1 mg/liter) has been confirmed by numerous epidemiological studies conducted in countries throughout the world (Horowitz, 1996). The average dietary intake by U.S. infants and children since 1980 in these areas has been close to 0.05 mg/kg/day (Table 8-1). The slightly higher average intakes by infants aged 2 to 6 months, reported by Singer and Ophaug (1979) were largely due to intake from formulas that had been manufactured with fluoridated water. Since then, most formula manufacturers in the United States have used low-fluoride water (Burt, 1992). Although the total amount of fluoride ingested daily by older children and adults is greater than by infants or young children, it is generally lower when expressed in terms of body weight. As noted earlier, average dietary fluoride intakes by adults living in fluoridated communities have ranged from 1.4 to 3.4 mg/day, or from 0.02 to 0.05 mg/kg/day for a 70 kg person.
As noted earlier, fluoride intake among infants varies widely, especially during the first 6 months of life, depending on whether the infant is fed human milk or formula and whether the formula is ready-to-feed or requires reconstitution with water. Human milk-fed infants receive about 0.01 mg/day (0.001 to 0.003 mg/kg). Infants fed a formula reconstituted with fluoridated water may receive as much as 1.0 mg/day. Some evidence shows that the prevalence of