Low-Dose Lithium 

“Lithium drinks were in huge demand for their reputed health-giving properties, so much so that the element was added to commercial drinks. 7-Up was originally called Bib-Label Lithiated Lemon-Lime Soda and contained lithium citrate right up until 1950. In fact, it’s been suggested that the 7 in 7-Up refers to the atomic mass of the lithium.”

—Fels, Anna. “Should We All Take a Bit of Lithium?The New York Times. September 13, 2014.

Low dose lithium might be a beneficial public health intervention on the level of fluoride.