A Rhode Island Hospital retrospective study published in the July 2014 issue of the journal, Alzheimer's & Dementia, showed that the participants with normal cognition at the start of the study who reported taking fish oil had fewer signs of Alzheimer's disease. These patients were followed every 6 months with MRI scans. Those people with a genetic disposition to Alzheimer's disease (APOE-4 gene) were at the highest risk.