Codon 54 polymorphism of the fatty acid binding protein 2 gene is associated with increased fat oxidation and hyperinsulinemia, but not with intestinal fatty acid absorption in Korean men

The alanine to threonine substitution at codon 54 (Ala54Thr) of the fatty acid binding protein 2 (FABP2) gene has been reported to be associated with increased fat oxidation and insulin resistance in several populations. It has been hypothesized that Ala54Thr substitution results in enhanced intestinal uptake of fatty acids and thereby an impairment of insulin action, but this hypothesis has not been proven in vivo. We studied the association between the Ala54Thr polymorphism of the FABP2 gene and intestinal 3H-oleic acid absorption, as well as basal insulin level, basal metabolic rate, and fat oxidation rate in 96 healthy young Korean men. Among our subjects, the allele frequency of the Ala54Thr substitution was 0.34. Subjects with Thr54-encoding allele were found to have a higher mean fasting plasma insulin concentration and a higher basal fat oxidation rate compared with the subjects who were homozygous for the Ala54-encoding allele. However, there was no significant difference in basal metabolic rate or 3H-oleic acid absorption according to the FABP2 gene polymorphism. These results suggest that the Ala54Thr substitution in the FABP2 gene is associated with increased fat oxidation and hyperinsulinemia in normal Korean men, but these effects are not mediated by an increase in the intestinal fatty acid absorption.