Although fluoride in water has been proven to prevent cavities, the results of a new study suggest that infants who consumed large amounts of fluoride-containing beverages may be at risk for dental fluorosis—discoloration of the primary teeth. Specifically, infants who drank the most water-based beverages (especially infant formulas made with water) were more likely to develop the condition.

The study's purpose was to determine whether infants' drinking patterns influenced their risk of fluorosis, with a focus on infant formulas. The researchers followed 677 children from 6 weeks of age until they had a dental checkup when they were at least 4 years old. Their parents periodically filled out detailed questionnaires about the children's diets. The study results, reported in the Journal of the American College of Nutrition (April 2004), showed that children who developed the condition consumed more water-constituted formula during infancy, compared with children who did not develop fluorosis.