Water fluoridation has been advocated by the U.S. Department of Health, the World Health Organization, and, as an effect, dental associations and national health councils all over the world. It has been argued that fluoride is a nutrient mineral that is essential for human health, and the optimum concentration is just under one milligram per litre. The WHO claims that “Any public water supplies with fluoride levels below 0.1 mg/l (ranging up to 0.3 for cooler climates) need to be fluoridated with artificial fluoride.” Yet no evidence supports that fluoride is an essential nutrient for humans, or that it has any oral health benefits.