Fatty acid-binding protein 2 Ala54Thr genotype is associated with insulin resistance and leptin levels changes after a high monounsaturated fat diet in obese non-diabetic patients

Background: It has been found that the expression of fatty acid binding protein 2 (FABP2) mRNA is under dietary control. This polymorphism was associated with high insulin resistance, and fasting insulin concentrations. Objective: The aim of our study was to investigate the influence of Thr54 polymorphism in the FABP2 gene on metabolic response, weight loss and serum adipokine levels secondary to a high monounsaturated fat hypocaloric diet. Design: A sample of 122 obese patients was analyzed in a prospective way. The hypocaloric diet had 1342 kcal, 46.6% of carbohydrates, 34.1% of lipids and 19.2% of proteins, with a 67.5% of monounsaturated fats, and lasted 3 months. Results: Fifty-five patients (45.1 %) had the genotype Ala54/Ala54 (wild group) and 67 (64.9%) patients a mutant genotype, Ala54/Thr54 (54 patients, 44.3%) or Thr54/Thr54 (13 patients, 10.7%). In wild group, body mass index (−1.5±1.2 kg/m2), weight (−4.1±3.6 kg), fat mass (−3.6±3.3 kg), waist circumference (−4.9±2.9 cm), insulin (−1.7±3.6 mUI/l), homeostasis model assessment of insulin resistance (HOMA-IR) (−0.6±1.8 units) and leptin levels decreased (−7.6±7.1 ng/ml). In mutant group, anthropometric parameters improved, without changes in biochemical parameters. Conclusion: Carriers of Thr54 allele have a different response than wild type obese, with a lack of decrease of insulin levels, leptin levels and HOMA-IR.