The new research is the first to measure community water fluoridation exposure during childhood and any potential impact on cognition up to age 80.
The paper is here
The new research is the first to measure community water fluoridation exposure during childhood and any potential impact on cognition up to age 80.
The paper is here
Perhaps has to do with the medium and the tendency of things to decay away. Maybe fluoride is stable in water, but something like Vitamin D would break down. Sunlight for example breaks down some things like that. I imagine water is probably a difficult medium to survive in for a lot of things.