Sodium fluoride is less toxic than most other fluoride salts. In cases of toxicity, extra calcium will bind with the fluoride, making a less soluble and less active compound.

Fluoride deficiency is less of a concern. Low fluoride or lack of fluoride use does correlate with a higher number of dental caries, given a less stability and strength of the bones and teeth in general. It is possible, that traces of fluoride are essential, but it is not clear whether it is a natural component of our body tissues. Low fluoride levels may correlate with a higher amount of bone fractures in the elderly, but that is usually in the presence of osteoporosis.

Requirements: There is no specific RDA for fluoride. Nor is it mandatory to add fluoride to the water. Many cities do not follow this much-supported preventive measure. On a worldwide level, there has been a lot of disappointment with the use of fluoridated water. People who drink fluoridated city water get about 1 mg. per day from it. Research shows that the amount in the average diet varies widely, depending on choices of foods and water use. Nonfluoridated water users take in between .35 mg. and 1.5 mg. per day, while the average city diet with fluoridated water contains about 2-3 mg. The suggested safe intake of fluoride (not necessarily the optimum, which we really do not know) is between 1.5 and 4.0 mg. per day. Amounts up to 15-20 mg. per day are probably well tolerated, though we do not know the long-range effects. And until we do, I personally would discourage overuse of fluoride. A complete review of the fluoride controversy, written from a global viewpoint, appeared in the August 1988 issue of Chemical Engineering.