Background: Epidemiologic and animal studies have suggested that dietary fish or fish oil rich in -3 fatty acids, for example, docosahexaenoic acid and eicosapentaenoic acid, may prevent Alzheimer disease (AD).Objective: To determine effects of dietary -3 fatty acid supplementation on cognitive functions in patients with mild to moderate AD.Design: Randomized, double-blind, placebo-controlled clinical trial.Participants: Two hundred four patients with AD (age range [mean±SD], 74 ± 9 years) whose conditions were stable while receiving acetylcholine esterase inhibitor treatment and who had a Mini-Mental State Examination (MMSE) score of 15 points or more were randomized to daily intake of 1.7 g of docosahexaenoic acid and 0.6 g of eicosapentaenoic acid (-3 fatty acid-treated group) or placebo for 6 months, after which all received -3 fatty acid supplementation for 6 months more.

ω-3 Fatty Acid Treatment in 174 Patients With Mild to Moderate Alzheimer Disease: OmegAD Study