Flavonoids and immune function in human: a systematic review.

Flavonoids, through a modulation of immune function, have been suggested to be involved in the role played by plant foods in disease prevention. We performed a systematic search in the MEDLINE database to review the effect of flavonoid-rich foods and flavonoids supplements on immune function. A total of 58 studies, were identified as suitable: 41 addressed in vivo proinflammatory cytokines and 15 measured ex vivo markers of immune function. According to our findings and on the basis of single food items, the number of studies in humans is limited and, for galenic supplements, only quercetin has been investigated. More evidences are needed to clarify the role of flavonoids as modulator of immune function in humans.