Nowadays, the study of the benefi cial effects of plant food components on human health is an extremely active research fi eld, but it still has to overcome important challenges. For many years, scientists have been worried about studying the biological activity of phytochemicals, looking for single miracle molecules with outstanding in vitro properties (resveratrol, quercetin, curcumin, etc…). Nevertheless, proving their effi cacy in human trials remains to be ascertained due to inter-
individual variability, and the design of an intervention represents a major challenge (1). Particularly, the paucity of clinical data for a rational use of polyphenols, including the lack of knowledge about effective dosage, actual chemical formulation, bioavailability, distribution in tissues, the effect of genetic variations, differences in gut microfl ora, the synergistic (or antagonistic) effects observed in extracts and, consequently, most safety issues.
The pathogenesis of many human chronic diseases is of multi-factorial character. This may be the reason why single polyphenols show limited effi cacy in pathologies such as obesity, cancer or cardiovascular diseases (2, 3). ...