"People with gum disease have worse mental functioning than those whose gums are healthy according to a UK study. The researchers had 6,693 adults in their twenties through seventies take cognitive performance tests. They found that, regardless of age, those with bleeding gums or tooth problems caused by inflamed gums scored worse. This finding suggests that system-wide inflammation due to gum disease causes damage to white matter in the brain, resulting in deficits in mental function. Flossing every day will help keep your gums healthy and your mind sharp."Related
Progressive brain damage via aging can also be minimized by eating fish. It's possible that the inflammation related to gum disease might be offset by eating fish... but you should probably floss anyway.
UPDATE 8/28/09: How about more reasons to floss; inflammation of the gums is also associated with an increased risk of pancreatic cancer.
This quote originated from the April 2009 issue of Best Life magazine: