If flossing lowers the risk of certain types of gum disease and certain types of gum disease are associated with Alzheimer’s, then maybe flossing is (indirectly) good for your brain.
https://www.health.harvard.edu/mind-and-mood/good-oral-healt...
https://www.health.harvard.edu/mind-and-mood/good-oral-healt...
They have much higher rates of these diseases, and recently in a court case the death of a farmers daughter has been shown to be caused by these pesticides.