• Fluoride is a mineral that occurs naturally in water, although it can also be a byproduct of industry. Adding fluoride to public water systems began as an experiment in Grand Rapids, Mich., in 1945, after a dentist at the National Institutes of Health theorized that it might prevent cavities in teeth. Over the next 11 years, tooth decay in Grand Rapids dropped by 60 percent.
  • a president could exert pressure on the F.D.A. to reverse its approval for a particular vaccine. Mr. Trump could also appoint judges predisposed to limiting the power of federal agencies, including the F.D.A.
  • If Congress were to repeal the Affordable Care Act, what would come next? When Mr. Trump was asked during his debate against Vice President Kamala Harris whether he had a replacement plan for the law, he said he had the “concepts of a plan.”