In a collagen-induced RA rat model (female Sprague Dawley), genistein (a polyphenol rich in soybeans) exerted anti-inflammatory activities; it maintained a balance between the T helper cell-1 (Th1) and Th2 cells by significantly suppressing IFN-γ and augmenting the production of IL-4 [182]. This evidence concerns the gene IL4 and rheumatoid arthritis.