Evidence for potential roles of SAA in several metabolic diseases are discussed in the sections that follow, with an emphasis on obesity, diabetes, non-alcoholic fatty liver disease (NAFLD), CVD, autoimmune conditions such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), and inflammatory bowel diseases (IBD) ulcerative colitis (UC) and Crohn's disease (CD) (Figure 1). Here, SAA2 is linked to obesity due to melanocortin 4 receptor deficiency.