Phytochemicals: Classification and occurrence

Phytochemicals, particularly flavonoids, may contribute to the health-promoting effects of a plant-based diet. The main dietary flavonoid subclasses are the flavones, flavonols, flavan-3-ols, isoflavones, flavanones, and anthocyanins. Diets high in flavonoids may not only reduce the risk of cardiovascular disease (CVD) and cancer but also, by protecting against cellular damage, may slow aspects of the aging process. There is still much to understand about their bioavailability, metabolism, mechanisms of action, optimal doses or, indeed, the actual compounds responsible for their health effects (parent/precursor versus metabolite). Although ‘naturally’ occurring, they require the same level of proof of efficacy and safety as synthetic pharmaceutical agents.