[eng] Due to the increased number of elderly people worldwide, nowadays one of the major medical and socio-economic challenges is to search strategies to combat the consequences of aging process, reducing the incidence of neurodegenerative diseases such as dementia. Dementia is a clinical syndrome of chronic and progressive symptoms characterized by multiple cognitive deficits associated with aging, which includes impairment in memory and in other cognitive functions to the extent that it interferes with daily function. In the last years oxidative stress and inflammation have been pointed out as the leading causes of brain aging and neurodegeneration. Therefore,an approach for preventing some brain age-related diseases, such as dementia, may be the consumption or administration of polyphenols,which are natural compounds present in edible plants. Due to their antioxidant and anti-inflammatory properties, polyphenolshave been suggested such as a beneficial strategy against the development of brain aging and neurodegeneration. This chapter summarizes the latest discoveries regarding how polyphenols exert positive effects combating the biochemical mechanisms that originate aging and dementia,such as oxidative stress, inflammation and the aggregation of abnormal folding proteins, among others.