05th April 2004

     
NEW YORK (Reuters Health) - Fluoride in water has helped prevent millions of cavities, but the results of a new study suggest that infants who drink large amounts of beverages that contain fluoride may be at risk for discoloration of their primary teeth.

In particular, infants who drank the most water-based beverages, particularly infant formulas made with water, were more likely to develop a condition called dental fluorosis when they were older.

But for most children, the level of fluoride in the water supply is unlikely to make them susceptible to fluorosis, the study's lead author emphasized.

Levels of dental cavities, or caries, have plummeted as a result of the fluoridation of water systems and the widespread availability of fluoridated toothpaste.

But as is the case with any nutrient, "some is good, but more is not necessarily better," according to Dr. Teresa A. Marshall of the University of Iowa College of Dentistry in Iowa City.

Exposure to too much fluoride of the nutrient during tooth development may change the structure of tooth enamel. These changes can lead to fluorosis, which is marked by tooth discoloration. Most cases are mild, but the condition is a signal that someone might have consumed too much fluoride when their teeth were forming.

Marshall and her colleagues set out to see if infants' drinking patterns influence their risk of fluorosis. They were particularly interested in looking at consumption of infant formulas.

During the 1970s, formula manufacturers reduced the amount of fluoride in their products, but some formulas must be mixed with water, which often contains fluoride.

Marshall and her colleagues followed 677 children from 6 weeks of age until a dental check-up when they were at least 4 years old. Parents periodically filled out detailed questions about their children's diet.

Compared to children who did not develop fluorosis, children who developed the condition consumed more water-constituted formula during infancy, the study found. They also drank more beverages overall, including water and fruit juice.

The results were published in the April issue of the Journal of the American College of Nutrition.

"Very young infants are unlikely to benefit from the caries-prevention effects of fluoride," Marshall told Reuters Health. "They may be at increased risk of dental fluorosis."

But most parents do not need to be overly concerned, according to Marshall. Based on fluoride levels typical of public water systems in the U.S., young children who drink a normal amount of water are unlikely to consume enough fluoride to develop fluorosis, she said.

But an infant who consumes fluoride from other sources, such as some soy or liquid concentrate formulas, may have an increased risk of dental fluorosis, according to the Iowa researcher. She added that a child who is a "big eater" could also be at increased risk.

SOURCE: Journal of the American College of Nutrition, April 2004.-By Merritt McKinney

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