A meeting Wednesday at the Food and Drug Administration about fluoride supplements became, at one point, a contentious back-and-forth over whether the ingestible tablets harm children’s microbiomes or play a vital role in helping protect them from tooth decay. Pediatric dentists consider the chewable tablets, available only by prescription, as particularly important for families who live in areas without fluoride in drinking water, who don’t have dental insurance or who can’t afford regular visits to dentists. Under Commissioner Marty Makary, however, the FDA has been taking steps to remove fluoride supplements from the market. A final decision isn’t expected until October, although advocates and critics at the meeting didn’t agree on basic scientific methods or even responsible dental practices.During the public meeting held in Silver Spring, Maryland, dental experts outlined the careful balance of getting the right amount of fluoride to their patients. Too little can result in weakened tooth enamel, said Dr. James Bekker, a member of the Utah Dental Association. Too much can lead to fluorosis, a condition that leaves white or brown spots on the teeth. “There are areas where we have community water fluoridation. We don’t need supplements in those areas,” said Bekker, who was invited to speak at Wednesday’s meeting. “But there are many areas of our country where we either don’t have community water fluoridation or we don’t have naturally occurring fluoride. In those places, supplements are the key to achieving that balance.” A panelist, Dr. Bill Osmunson, a retired dentist who now works for the Fluoride Action Network, an anti-fluoride group, peppered Bekker about how he determines whether a child needs fluoride supplements. “You ask where they live?” Osmunson asked. “You ask where they go to school?” Bekker explained how he does comprehensive assessments of his young patients, including reviewing dietary issues and whether they use other supplements, before he prescribes the fluoride tablets or drops. “Really, you ask all those questions?” Osmunson said. “You bet,” Bekker said. Osmunson’s “inquisition of Dr. Bekker was a tactic to attempt to make him look incompetent,” said Dr. Johnny Johnson, president of the American Fluoridation Society. “That type of exchange is meant as a popularity contest.” Johnson spoke in favor of the supplement during a public comment session. Osmunson and other critics relied on data that didn’t necessarily prove their criticism of the products.For example, Makary, the FDA commissioner, has said ingested fluoride alters the gut microbiome. His assertion appears to hinge on a 2023 review of research by scientists in Ireland. That analysis noted that animal studies suggested that ingesting fluoride affected the microbiome but that none of the studies examined fluoride and the human microbiome. The researchers concluded that any possible effect of fluoride on the microbiome is “still in its early days, and studies investigating the impact of fluoride on the human microbiome have only begun to appear in the literature.”One of the authors of that study also spoke at Wednesday’s meeting. “Fluoride consumption at levels which we consider good for maintaining good oral health probably have limited impact on the oral and gut microbiomes,” said Gary Moran of Trinity College Dublin in Ireland. But, he added, “we certainly need more studies.”There was no vote for or against fluoride supplements. Dr. David Krol, a representative of the American Academy of Pediatrics, spoke in favor of fluoride supplements as one of many tools physicians need to ensure their patients’ teeth are as strong as possible. “Fluoride supplementation, as well as conversations about diet and conversations about hygiene, are the kinds of things that take place between pediatricians and patients,” Krol said. “We have to have that opportunity to continue those conversations and have those multifactorial tools to address this disease.”Even though Medicaid covers oral health for children, fewer than half went to the dentist at least once a year.Cavities that erupt in those kids’ mouths get worse if they’re left untreated, and they can cause widespread damage. The decay “eats away at the bone” around the tooth and sometimes gets into the bloodstream, said Dr. Steven Levy, a professor of preventive and community dentistry at the University of Iowa.“This is more than just a garden-variety, middle-class person’s experience with a cavity,” he said.Major public health groups, including the American Academy of Pediatrics and the U.S. Preventive Services Task Force, recommend prescribing supplements for children starting at 6 months if the water supply isn’t fluoridated.Fluoride supplements are often given to kids from age 5 until they have their permanent teeth, around age 13 or 14, Bekker said in an interview before the meeting. Babies get drops until they’re old enough to chew tablets. They’re generally inexpensive.Over-the-counter vitamins and supplements don’t contain fluoride. Fluoride is available over the counter only in toothpaste and mouthwashes.Makary also objects to the fluoride supplements because they aren’t approved by the FDA. Because the supplements had been in use for decades before Congress mandated that drug manufacturers show that their products were not only safe but also effective, they were never required to go through the approval process. For almost as long as the supplements have been prescribed, critics have been concerned about the lack of rigorous data showing their potential health effects and how they protect kids’ teeth.“I think we really need to understand the benefits,” said Linda Birnbaum, a toxicologist and former director of the National Institute of Environmental Health Sciences and the National Toxicology Program. Birnbaum also spoke during the FDA meeting.Dr. Brett Kessler of the American Dental Association acknowledged that prescription fluoride supplements should be administered only after a “thoughtful decision” based on conversations between physicians and families.“I’m hoping we can all take a breath, filter out all the noise and not give in to the anti-fluoride hysteria,” he said during the meeting.