Did you read the article? 'The activist groups had a growing, but highly controversial, body of scientific evidence to draw from. Scientists had long known tha

Did you read the article? 'The activist groups had a growing, but highly controversial, body of scientific evidence to draw from. Scientists had long known that very high doses of fluoride can damage bones and teeth. Since the early 1990s, a modest body of scientific research has also suggested that fluoride can harm brain development, leading to measurable drops in children’s IQ. Many of those early studies, experts say, were poorly done. And some took place in communities where fluoride naturally occurs in the water at levels much higher than the 0.7 milligrams per liter that U.S. communities currently add to their tap water. Still, the signs of negative IQ effects were consistent enough for some experts to raise questions. “More research is needed to clarify the effect of fluoride on brain chemistry and function,” a panel of experts convened on behalf of the EPA wrote in 2006. Starting in 2015, the National Toxicology Program, an office housed within the National Institutes of Health, began preparing a major review of fluoride research — at least partly in response to a nomination from the Fluoride Action Network. Around the same time, the government institute that houses the NTP helped fund new studies in Canada and Mexico that looked at levels of fluoride in pregnant women’s urine, and then investigated whether those levels were correlated with a drop in IQ in their offspring. The researchers found some signs of an effect. The results concerned some environmental health researchers. “As the literature continued to accumulate, we were more and more convinced that there were no single flaws that could explain the consistency in the findings,” John Bucher, a retired NTP toxicologist and a lead author of the report, told Undark in an interview conducted late last year. In August, after years of delays, the NTP released its final report, finding, with moderate confidence, that fluoride exposures at levels above 1.5 mg/L “are consistently associated with lower IQ in children.”' There are serious researchers finding mixed results based on the levels, not just crunchy social media accounts.