Low levels of both insulin and insulin-like growth factors appear to cause cell loss and the shrinking of the brain that result in dementia . . . . [T]he findings offer real hope that the progression of dementia in those with conditions such as Alzheimer's, diabetes and Parkinson's disease may someday be prevented. . . . About 80 percent of Alzheimer's patients have a history of diabetes or pre-diabetes. Diabetics also are at a higher risk of developing dementia. . . .[T]he gradual loss of both insulin and insulin-like growth factors combined with aging and disease probably increases the risk of brain shrinkage. . . . [Therefore] "it may be possible to develop a treatment that prevents brain atrophy and prevents the progression of dementia."
Dementia (i.e. reduced mental abilities, often associated with aging) affects five million people in the U.S. and the numbers may double as the baby boomers age.
Also, since obesity is strongly linked to diabetes, controlling obesity may, in turn, reduce one's risk of Alzheimer's disease.