According to epidemiological studies, some of the naturally occurring dietary flavonoid such as quercetin (3,5,7,3,4-pentahydroxyflavone), kaempferol (3,5,7,4tetrahydroxyflavone) and apigenin (4,5,7-trihydroxyflavone) also contribute in the activation process of PPAR-γ, which in turn are associated to the diminishing incidence of certain disorders: diabetes, coronary heart diseases and various types of cancer [87,88]. This evidence concerns the gene PPARG and diabetes mellitus.