INTESTINAL FATTY-ACID-BINDING PROTEIN VARIATION ASSOCIATED WITH VARIATION IN THE RESPONSE OF PLASMA-LIPOPROTEINS TO DIETARY FIBER

Increased dietary fibre intake is a component of prudent dietary advic e, although the mechanism of its beneficial effect is unclear. Further more, plasma lipoprotein response to dietary fibre seems to vary both between individuals and according to the type of fibre consumed. Two c ommon genetic variants, A54 and T54, of the intestinal fatty acid-bind ing protein gene (FABP2) have different in vitro binding affinities fo r long-chain fatty acids. We have hypothesized that variation in FABP2 would be associated with interindividual variation in the response of plasma lipoproteins to either dietary soluble or insoluble fibre. We studied 43 subjects who participated in a year-long cross-over study o f the effect of insoluble and soluble fibre on plasma lipoproteins. We tested for associations between FABP2 genotypes and the response of p lasma lipoproteins to dietary fibre. When compared with subjects homoz ygous for FABP2 A54, we found that subjects with FABP2 T54 had signifi cantly greater decreases in plasma total and low-density Lipoprotein ( LDL)-cholesterol and apoB during the period when the diet was high in soluble fibre than during the period when the diet was high in insolub le fibre. Furthermore, compared with subjects with the FABP2 A54 allel e, subjects with the FABP2 T54 allele had significantly lower secretio n of total fecal bile acids, but this did not increase with dietary so luble fibre. Genetic variation in FABP2 may thus contribute to interin dividual variation in the response of plasma lipoproteins to different dietary fibres, but the mechanism does not appear to be related to in creases in fecal bile acid secretion.