The effects of retinol on postprandial parameters in men with different FABP2 promoter haplotypes

The fatty acid binding protein 2 (FABP2) mediates the intestinal uptake of fatty acids. We and others have identified six FABP2 promoter polymorphisms which result in two haplotypes, A and B. Reporter-gene assays indicated different activity in FABP2 promoter alleles A and B and different responsiveness to PPAR ligands. IN SILICO analysis revealed different putative binding sites in FABP2 haplotypes for retinoid-dependent transcription factors. Therefore, we assumed that retinol supplementation may effect postprandial fat uptake differently in men with FABP2 promoter haplotype A and B. To test this hypothesis, we administered 5000 I.U. retinol/day for 8 weeks to 19 homozygotes for AA and 21 homozygotes for BB and assessed the alteration of postprandial triglycerides during this intervention. FABP2 genotype groups did not significantly differ in anthropometric and laboratory parameters. The alteration of postprandial triglycerides did not differ significantly between genotypes during intervention. This also held true after adjustment for BMI. Furthermore, in a subgroup which had a combination of promoter and common exon polymorphism, the alteration of the postprandial triglycerides did not differ between genotypes. In conclusion, the postprandial triglyceride metabolism of FABP2 promoter AA and BB did not respond differently to retinol administration even though IN SILICO analysis suggested this.