With the republication of Grant (18), the first paper providing epidemiologic evidence linking diet to the development of Alzheimer's disease (AD), it is an appropriate time to review the findings and hypotheses therein in light of the subsequent literature. The main findings, that dietary fat and energy in old age are high risk factors, while fish and cereals are risk-reduction factors, have been supported in various recent epidemiologic studies. Diet contributes to the development of AD through modulating oxidative stress and inflammation, which is also linked to oxidative stress, but may also arise from series 2 prostaglandins. Thus, as one ages, dietary modifications and additional supplements designed to reduce free radical production and inflammation provide a significant measure of reduction in risk for the development of AD.