OBJECTIVE: To investigate the relationship between serum omega-3 polyunsaturated fatty acid (omega-3PUFA) and insulin resistance (IR) in patients with type 2 diabetes mellitus and non-alcoholic fatty liver disease (NAFLD).

METHODS: This trial involved 51 patients of type 2 diabetes mellitus with NAFLD (G4 group), 50 patients of type 2 diabetes alone (G3 group), 45 patients of NAFLD alone (G2 group) and 42 healthy control subjects (G1 group). Serum omega-3PUFA profile was analyzed with capillary gas chromatography. Insulin resistance was assessed by homeostasis model assessment (HOMA-IR). ALT, AST, gamma-glutamyltransferase (GGT) and serum lipids were measured.

RESULTS: The levels of HOMA-IR were higher in G4 group than those in G3, G2 and G1 group (4.90 + or - 2.54 vs 2.38 + or - 1.23, 2.20 + or - 1.15, 1.13 + or - 0.42; P < 0.05). The level of ALT, AST, GGT, TC, TG, LDL-C were higher in G4 group than those in G3, G2 and G1 group (P < 0.05). The level of omega-3PUFA was significantly lower in G4 group than those in G3, G2 and G1 group (5.68 + or - 2.02 vs 7.17 + or - 2.38, 6.97 + or - 2.32, 10.08 + or - 2.76; P < 0.05). omega-3PUFA concentration was negatively correlated with HOMA-IR, TC, TG and LDL-C (r = -0.491, -0.376, -0.462, -0.408, P < 0.05).

CONCLUSIONS: Serum omega-3PUFA is significantly decreased in patients with type 2 diabetes mellitus and NAFLD. Serum omega-3PUFA is negatively correlated with insulin resistance. omega-3PUFA plays a very important role in the development of diabetes mellitus and NAFLD.