Biochemical deficits and cognitive decline in brain aging: Intervention by dietary supplements.

The aging of brain in the absence of neurodegenerative diseases, usually called non-pathological brain aging or normal cognitive aging, is characterized by an impairment of memory and cognitive functions. The underlying cellular and molecular changes in the aging brain that include oxidative damage, mitochondrial impairment, changes in glucose-energy metabolism and neuroinflammation have been reported widely from animal experiments and human studies. The cognitive deficit of non-pathological brain aging is the resultant of such inter-dependent and reinforcing molecular pathologies which have striking similarities with those operating in Alzheimer's disease which causes progressive, irreversible and a devastating form of dementia and cognitive decline in the elderly people. Further, this article has described elaborately how nutraceuticals present in a wide variety of plants, fruits and seeds, natural vitamins or their analogues, synthetic antioxidants and other compounds taken with the diet can ameliorate the cognitive decline of brain aging by correcting the biochemical alterations at multiple levels. The clinical usefulness of such dietary supplements should be examined both for normal brain aging and Alzheimer's disease through randomized controlled trials.