Antioxidants and Alzheimer's disease: from bench to bedside (and back again)

Accumulating evidence from both animal and human studies indicates a major role for oxidative damage in the pathogenesis of Alzheimer's disease, occurring even before symptoms arise and both beta-amyloid-containing plaques and neurofibrillary tangles are formed. This raises the possibility of preventing, or at least slowing down, the progression of Alzheimer's disease by the use of antioxidants. In this review, we present recent studies on the association between oxidative stress and Alzheimer's disease pathology, and on the efficacy of dietary, exogenous antioxidants to prevent or attenuate the progression of Alzheimer's disease.

Recent prospective studies have indicated that dietary intake of several exogenous antioxidants is associated with a lower risk for Alzheimer's disease. This suggests that people at risk for developing Alzheimer's disease or being in the early phases of this disease may benefit from intervention with exogenous antioxidants. The clinical studies carried out so far, however, do not provide the final answer to whether antioxidants are truly protective against Alzheimer's disease.

There is compelling evidence that oxidative stress is involved in Alzheimer's disease pathogenesis, and several lines of evidence indicate that administration of antioxidants may be useful in prevention and treatment of Alzheimer's disease. Further clinical studies, based on larger cohorts studied over a longer period of time, are needed, however, to test this hypothesis. Furthermore, for the future one might expect balanced upregulation of both exogenous and endogenous antioxidants as one of the best treatment strategies for preventing or at least slowing down the progression of Alzheimer's disease.