IN THIS ISSUE of the ARCHIVES, Morris and colleagues1 report data from a remarkable prospective study of Alzheimer disease (AD) in a biracial community in Chicago, Ill (815 people, aged 65-94 years). They found that subjects who ate fish once a week or more had a 60% lower risk for developing AD than those who consumed fish less frequently. The data were statistically adjusted to correct for the effects of age, sex, ethnicity, education, stroke, hypertension, heart disease, apolipoprotein E (apo E) genotype, total caloric intake, and consumption of other fats or vitamin E. Intake of long-chain n-3 polyunsaturated fatty acids (PUFAs) and docosahexaenoic acid (omega-3) was associated with a reduced risk of developing AD over the 4 years of the study. Intake of α-linolenic acid or eicosapentaenpoic acid was not associated with disease after adjustment. Intake of α-linolenic acid, found in vegetable oils and nuts, was protective only in people with the apoE ϵ4 allele, and total n-3 fatty acid intake was protective only in women. These data and other work in the area1- 2 suggest that consumption of PUFAs found in fish, vegetable oils, and nuts may reduce AD risk.