Resveratrol is derived from plants and is found in highest levels in red wine and the skin of red grapes. A recent study reported that monthly and weekly consumption of red wine is associated with a lower risk of dementia. There is compelling evidence that caloric restriction can improve overall health by activating a class of enzymes known as sirtuins. Resveratrol is a substance found in some plants that directly activates sirtuins, mimicking the effects of caloric restriction. It may also affect regulatory pathways of diseases of aging, including Alzheimer's disease.

In this study, 120 participants with mild to moderate dementia due to probable Alzheimer's will be randomly assigned to treatment with either resveratrol starting at 500 mg once daily or matching placebo for 12 months. The dose will be increased at 13-week intervals to a maximum of 1 gram twice daily. Participants will undergo venous blood draws for biomarker analysis at baseline and at 52 weeks; participants will also undergo two lumbar punctures for biomarker analyses of cerebrospinal fluid (CSF) at baseline and at week 52. Participants will undergo magnetic resonance imaging (MRI) to measure rate of whole-brain and regional atrophy at screening, week 13, and week 52 visits.

A small group of 15 participants will be asked to take part in a more detailed 24-hour pharmacokinetic substudy that will measure resveratrol levels over a 24-hour period. Blood samples will be collected at 15 different time points. This 24-hour pharmacokinetic sampling in the subgroup will occur after the first dose following baseline, after the first dose at each dose increment (weeks 13, 26 and 39), and after the final dose (week 52).