 Long interested in the effect of diet on the teeth, McCollum was awarded medals by the Connecticut and Ohio dental societies and was a fellow of the New York society as well as an honorary member of the American Academy of Dental Medicine.His paper "The Effect Of Additions Of Fluorine to the Diet Of The Rat On the Quality Of the Teeth" (1925) described how excessive florine would negatively affect dental health in rats.Nonetheless, McCollum would later become a supporter of water fluoridation from the beginning of recorded evidence for the intervention.