The recent observation that FFA2-deficient mice show exacerbated or unresolving inflammation in models of colitis, arthritis and asthma, and that germ-free wild-type mice, unable to convert fiber to SCFAs, show similarly exacerbated inflammatory conditions, indicate that SCFAs and FFA2 represents a link between a fiber-rich diet and its beneficial effects on the immune system and inflammation (Maslowski et al., 2009). This evidence concerns the gene FFAR2 and Arthritis.