Flavonoids and the brain: interactions at the blood–brain barrier and their physiological effects on the central nervous system

Over the past few years there has been an exponential growth in the number of reports describing the effects of nutritional modulation on aging and age-related diseases. Specific attention has been directed toward the beneficial effects afforded by dietary antioxidants, in particular those from fruit and vegetables, in ameliorating age-related deficits in brain performance. The rationale for studying the effects of dietary intervention stems from evidence implicating free radicals in aspects related to the aging process. Age-dependent neuropathology is a cumulative response to alterations induced by reactive oxygen species. Therefore cognitive aging, according to this hypothesis, should be slowed, and possibly even reversed, by appropriately increasing levels of antioxidants or decreasing overproduction of free radicals in the body.