Revisiting dietary antioxidants, neurodegeneration and dementia.

Epidemiological studies suggest there is marginal benefit that dietary antioxidants reduce risk of Alzheimer type of dementias. Yet cumulative biological evidence indicates oxidative and nitrosative stresses are precursors of neurodegenerative and neurovascular processes. Different dietary flavonoids and polyphenols found in fruits, vegetables, and spices such as curcumin offer neuroprotection through different mechanisms. A study in this volume shows that tetrahydrocurcumin confers protection against amyloid [beta]-induced toxicity by reducing reactive oxygen species and retaining mitochondrial membrane potential. Alzheimer's disease is a complex disorder. A single target through use of antioxidants may be effective in some but multiple approaches for its control seem to be necessary.