You Ask, We Answer: Is it safe to use fluoridated water to reconstitute infant formula?

With the release of the ADA’s new edition of "Fluoridation Facts," readers can learn the answers to hundreds of frequently asked questions about community water fluoridation and the latest scientific research. "Fluoridation Facts" — the Association’s free resource on fluoridation that examines the mineral’s effectiveness, safety, practice and cost-effectiveness — works to assist policymakers and the general public in making informed decisions about fluoridation. The new edition contains more than 400 references and 10 new Q&A’s for a total of 69 questions answered over 114 pages. 

In an ongoing series, the ADA News is delving into many questions explored in the book through conversations with experts about fluoridation information and misinformation — from overall effectiveness to whether ingesting fluoride impacts IQ, health and reproduction.

Steven Levy, D.D.S., University of Iowa dental professor and international expert on fluoride intake, discussed the safety of using fluoridated water to reconstitute infant formula — question No. 28 in “Fluoridation Facts.”

Dr. Levy said evidence continues to support the safety of using community-fluoridated water to reconstitute infant formula, while acknowledging a small associated risk of mild dental fluorosis, which is a change in the appearance of tooth enamel that occurs only while teeth are developing. Mild forms present as faint white spots or streaks and do not affect tooth function. Moderate and severe fluorosis — which can involve staining or pitting — occur only with fluoride levels far above those used in community water fluoridation, he said.

Dr. Levy emphasized that research has long shown the benefits of water at about 1 part per million of fluoride, noting that high-fluoride water, or 2 to 3 ppm or more, is linked with more severe forms of fluorosis, while optimally fluoridated water provides substantial cavity prevention with minimal cosmetic risk.

“We generally recommend that it is okay for most parents to use fluoridated water with their infants, including when they reconstitute infant formula,” Dr. Levy said.

Infants who consume large volumes of powdered formula reconstituted with fluoridated water may ingest more fluoride than is ideal for their age, which can slightly increase the likelihood of mild fluorosis. However, Dr. Levy noted that online discussions often misrepresent and exaggerate the issue when opponents display images of advanced fluorosis as if they were typical.

Dr. Levy reiterated that fluoridated water remains appropriate for most families. For parents who are particularly concerned about even mild fluorosis, he said clinicians may recommend the optional use of lower-fluoride or fluoride-free water for formula preparation.

“We generally recommend that dentists and physicians feel comfortable recommending their patients use fluoridated water, but if there is concern expressed, then that’s where you would recommend lower fluoride water,” he said. “If it’s just an occasional bottle for four ounces once or twice a day or something, then that’s where you probably wouldn’t bother with it. But if it’s a frequent regular thing, and they’re getting larger quantities, then it’s really good to consider doing that.”