Fluoride is a poison, toxic tor a small child in doses of 500 mg, and toxic to an adult in doses of a few thousand mg. It is a commonly used rat poison that kills by robbing the brain of the ability to absorb oxygen. In the form of hydrofluoric acid, it is responsible for the deaths of more famous chemists than any other single compound: Humphrey Davy died trying to isolate fluorine; Paul Louyet and Jerome Nickles, too. Thomas Knox nearly died, and Henri Moissan’s life was shortened. Louis-Joseph Gay Lussac, George Knox, and Louis- Jacques Thenard suffered burns and similar, George Knox was bedridden for three years. Among the symptoms of fluoride poisoning is severe joint pain and that your brain turns blue.

In low doses, though, fluoride is thought to be safe and beneficial. This is a phenomenon known as hormesis. Many things that are toxic at high doses are beneficial at low. Most drugs fall into this category, and chemotherapy works this way. Diseased cells are usually less-heartythan healthy ones. Fluoride is associated with strong teeth, and few cavities. It is found at ppm levels many well water systems, and has shown no sign of toxicity, either for humans or animals at these ppm levels. Following guidelines set by the AMA, we’ve been putting fluoride in drinking water since the 1960s at concentrations between 0.7 and 1.2 ppm. We have seen no deaths or clear evidence of any injury from this, but there has been controversy. Much of the controversy stems from a Chinese study that links fluoride to diminished brain function, and passivity (Anti-fluoriders falsely attribute this finding to a Harvard researcher, but the Harvard study merely cites the Chinese). The American dental association strongly maintains that worries based on this study are groundless, and that the advantage in lower cavities more than off-sets any other risks. Notwithstanding, I thought I’d take another look. The typical US adult consumes 1-3 mg/day the result of drinking 1-3 liters of fluoridated water (1 ppm = 1 mg/liter). This < 1/1000 the toxic dose,

While there is no evidence that people who drink high-fluoride well water are any less-healthy than those who drink city water, or distilled / filtered water, that does not mean that our city levels are ideal. Two months ago, while running for water commissioner, I was asked about fluoride, and said I would look into it. Things have changed since the 1960s: our nutrition has changed, we have vitamin D milk, and our toothpastes now contain fluoride. My sense is we can reduce the water concentration. One indication that this concentration could be reduced is shown below. Many industrial countries that don’t add fluoride have similar tooth decay rates to the US.

World Health Organization data on tooth decay and fluoridation.

This chart should not be read to suggest that fluoride doesn’t help; all the countries shown use fluoride toothpaste, and some give out fluoride pills, too. And some countries that don’t add fluoride have higher levels of cavities. Norway and Japan, for example, don’t add fluoride and have 50% more cavities than we do. Germany doesn’t add fluoride, and has fewer cavities, but they hand out fluoride pills, To me, the chart suggests that our levels should go down, though not to zero. In 2015, the Department of Health recommend lowering the fluoride level to 0.7 ppm, the lower end of the previous range, but my sense from the experience of Europe is that we should go lower still. If I were to pick, I’d choose 1/2 the original dose: 0.6 to 0.35 ppm. I’d then revisit in another 15 years.

Having picked my target fluoride concentration, I checked to see the levels in use in Oakland county, MI, the county I was running in. I was happy to discover that most of the water the county drinks, that provided by Detroit Water and Sewage, NOCWA and SOCWA already have decreased levels of 0.43-0.55 ppm. These are just in the range I would have picked, Fluoride concentrations are higher in towns that use well water, about  0.65-0.85 ppm. I do not know if this is because the well water comes from the ground with these fluoride concentrations or if the towns add, aiming at the Department of Health target. In either case, I don’t find these levels alarming. If you live none of these town, or outside of Oakland county, check your fluoride levels. If they seem high, write to your water commissioner. You can also try switching from fluoride toothpaste to non-fluoride, or baking soda. In any case, remember to brush. That does make a difference, and it’s completely non-toxic.

Robert Buxbaum, January 9, 2017. I discuss chloride addition a bit in this essay. As a side issue, a main mechanism of sewer pipe decay seems related to tooth decay. That is the roofs of pipe attract acid-producing, cavity causing bacteria that live off of the foul sewer gas. The remedies for pipe erosion include cleaning your pipes regularly, having them checked by a professional once per year, and repairing cavities early. Here too, it seems high fluoride cement resists cavities better.