Dietary flavonoids for brain health: Molecular mechanisms and functional food applications

Neurodegenerative diseases affecting learning and memory pose a major public health problem, particularly in ageing populations. Despite extensive research, the mechanisms underlying neurodegeneration and associated cognitive decline remain incompletely understood. This review summarises the current state of knowledge on flavonoids - plant-derived compounds that show considerable promise for supporting and preserving brain health. Flavonoids exhibit antioxidant and anti-inflammatory properties, can cross the blood-brain barrier, and modulate brain regions involved in cognition, as well as the gut-brain axis and key molecular pathways. These features make them promising adjuncts in strategies aimed at preventing or mitigating neurodegenerative diseases and age-related cognitive decline. However, their neuroprotective efficacy depends not only on biological activity but also on stability during food processing and overall bioavailability, both of which are strongly influenced by chemical structure and the food matrix. Processing conditions, including thermal treatment, may affect flavonoid stability, while the food matrix and meal composition modulate their release, bioaccessibility, and absorption. Additionally, potential interactions with drug metabolism and transport pathways warrant careful consideration. Accordingly, effective dietary approaches should prioritise the regular consumption of a diverse range of minimally processed, flavonoid-rich foods, alongside attention to preparation methods and overall dietary composition to optimize bioavailability and maximize potential health benefits.