Dementia and age-related macular degeneration (AMD) are major causes of disability in the elderly. n-3 Fatty acids, particularly docosahexaenoic acid (DHA), are highly concentrated in brain and retinal tissue and may prevent or delay the progression of dementia and AMD. Low dietary intakes and plasma concentrations have been reported to be associated with dementia, cognitive decline, and AMD risk. The major dietary sources of DHA are fish and fish oils, although dietary supplements are available. At this point, it is not possible to make firm recommendations regarding n-3 fatty acids and the prevention of dementia and AMD. Our own unpublished observations from the Framingham Heart Study suggest that > or =180 mg/d of dietary DHA (approximately 2.7 fish servings/wk) is associated with an approximately 50% reduction in dementia risk. At least this amount of DHA is generally found in one commercially available 1-g fish oil capsule given daily.