Actually, almost our entire food supply is fluoridated. The USDA has put together a fluoride in foods database so that we don’t eat too much. However, most people don’t even know they should restrict their daily fluoride intake.
Fluoride is also found naturally in ocean fish and tea and is in many medicines. Fluoride containing pesticide residues also are present on some produce and grains. Sulfuryl fluoride has replaced methyl bromide as a post harvest fumigant - adding even more fluoride into our diets.
Meanwhile, fluoride is neither a nutrient nor essential for healthy teeth. So avoiding fluoride has no downside (I know that’s hard to believe) And fluoride ingestion does not reduce tooth decay. However, fluoride applied to the teeth does harden the outer enamel. But some say it hides rather than prevents tooth decay as huge cavities are found under sound-looking enamel when it is poked or proded.
I've been on reverse osmosis water and low/no fluoride foods since Dec. '99. It's made a world of difference in my quality of life (minimal back and joint pain, etc.).