Every comment thread about fluoridation on HN goes like this. Most countries that don’t fluoridate their water don’t do so either because they fluoridate someth

Every comment thread about fluoridation on HN goes like this. Most countries that don’t fluoridate their water don’t do so either because they fluoridate something else (table salt) or because their natural groundwater contains sufficient fluoride, or because dietary trends in those areas already provide dietary fluoride. Western Europe and Latin America are examples of (1), Central Europe is an example of (2), and much of Asia is (2) or (3). And this is the point: if you have naturally occurring fluoride at safe levels, you shouldn’t add it. If you have it at unsafe levels (which much of the world does!), you should defluoridate your water. But the body of evidence is overwhelming that 0.7mg/L for fluoridation is not a significant public health risk, especially in contrast with its tangible benefits.