Flavonoids are commonly found in fruits, vegetables, and plant-derived foods and may
promote various health benefits when included in the diet. The biological activity of flavonoids is
normally associated to their potent antioxidant and anti-inflammatory effects, since oxidative stress
is associated to conditions such as diabetes, obesity, cardiovascular and neurodegenerative diseases.
Additionally, flavonoids may be related to metabolic diseases through their effects on inflammatory
mediators and pathways, barrier integrity and gut microbiota composition. The extensive
metabolism undergone by flavonoids in humans and the individual differences in their bioavailability
to target organs hinder the interpretation of results from cell and animal models. Prospective human
studies therefore provide an important perspective. In the field of neurodegenerative disease,
carefully designed cohort studies have uncovered important associations between flavonoid intake
and reduction in dementia risk, especially regarding specific flavonols, but also anthocyanins. Alternative
mechanisms of action, such as changes in the gut microbiota or modulation of the production
of toxic proteins, such as amyloid and tau, likely account for an important component of their
positive effects, and their elucidation may lead to public health benefits of large magnitude.