Comparison of the acute response to meals enriched with cis- or trans-fatty acids on glucose and lipids in overweight individuals with differing FABP2 genotypes.

Trans-fatty acids have been implicated as a risk factor for cardiovascular disease and diabetes. In addition, a polymorphism at codon 54 (Ala54Thr) in the fatty acid-binding protein 2 (FABP2) gene has been suggested to modify an interaction between dietary fat and insulin sensitivity. We examined the postprandial metabolic profiles after meals enriched with C18:1trans- relative to a similar meal with C18:1cis-fatty acid in individuals who were either FABP2 Ala54 homozygotes or Thr54 carriers. Moderately overweight men and women ate 2 breakfast test meals, separated by 1 week, each providing 40% of their daily energy requirement and containing 50% of energy as fat. In one meal, 10% of energy was from C18:1trans, and in the other meal, the C18:1trans was replaced with C18:1cis. Metabolic parameters were assessed during an 8-hour period. Insulin and C-peptide levels increased more after the C18:1trans meal, and this was associated with a greater fall in free fatty acids. Postprandial glucose levels and oxidation of fatty acids and carbohydrate were not different between the 2 test meals. The Thr54 allele for FABP2 increased the rise in postprandial glucose but not triacylglycerols. Fractional triacylglycerol synthetic rates were higher after consumption of the C18:1trans meal relative to the C18:1cis meal only in Thr54 carriers. These data show that a single meal enriched with C18:1trans-fatty acids can significantly increase insulin resistance, and that in the presence of the FABP2 Thr54 allele, may contribute to increased partitioning of glucose to triacylglycerols and insulin resistance.