title: Long-term effect of soluble-fiber foods on postprandial fat metabolism in dyslipidemic subjects with apo E3 and apo E4 genotypes.
abstract: To determine the long-term effect of soluble fiber on postprandial fat metabolism, we studied 33 dyslipidemic subjects, 16 with apolipoprotein (apo) E3/3 (E3) and 17 with E3/4 or E4/4 (E4) genotypes. They ate preweighed low-fat (20% of energy), high-fiber (> 5.7 g/MJ) diets for two 4-mo periods separated by a 2-mo washout period according to a randomized, crossover design. One diet contained foods rich in insoluble fiber and the other foods rich in soluble fiber. On 1 d during the last 2 wk of each diet, subjects ingested a standard, fiber-free, fatty liquid meal containing retinyl palmitate as a marker of intestinally derived lipoproteins. Plasma samples were obtained at hourly intervals for 10 h. Compared with the insoluble-fiber diet, soluble fiber reduced fasting plasma total cholesterol in both E3 (6.6 +/- 2.1%, P = 0.007)and E4 subjects (5.6 +/- 2.1%, P = 0.017). Soluble fiber increased fecal total bile acid output in both E3 (76 +/- 18%, P < 0.001) and E4 subjects (85 +/- 19%, P < 0.001). The incremental area under the chylomicron triacylglycerol response curve was significantly greater after soluble fiber than after insoluble fiber in E3 (3.56 +/- 0.56 compared with 2.87 +/- 0.38 mmol x h/L, respectively, P = 0.046) but not in E4 subjects (5.19 +/- 0.78 compared with 4.92 +/- 0.81 mmol x h/L). Kinetic analysis suggested an increase in retinyl palmitate absorption in E3 subjects after soluble fiber, but no difference in E4 subjects. These results suggest that a long-term increase in dietary soluble fiber has no effect on postprandial fat metabolism in subjects with an apo E3/4 or E4/4 genotype. However, soluble fiber enhances apparent fat absorption in E3 subjects, which could be due to an increased bile acid pool and increased micelle formation.
authors.affiliation: Department of Nutritional Sciences, University of Toronto, Ontario, Canada.
authors.forename: T M
authors.initials: TM
authors.lastname: Wolever
authors.forename: R A
authors.initials: RA
authors.lastname: Hegele
authors.forename: P W
authors.initials: PW
authors.lastname: Connelly
authors.forename: T P
authors.initials: TP
authors.lastname: Ransom
authors.forename: J A
authors.initials: JA
authors.lastname: Story
authors.forename: E J
authors.initials: EJ
authors.lastname: Furumoto
authors.forename: D J
authors.initials: DJ
authors.lastname: Jenkins
mesh_terms: D053318:Apolipoprotein E3; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics*; D002784:Cholesterol / Q000097:blood; D002914:Chylomicrons / Q000096:biosynthesis; D004041:Dietary Fats / Q000378:metabolism*; D004043:Dietary Fiber / Q000008:administration & dosage*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D019518:Postprandial Period; D012995:Solubility; D014280:Triglycerides / Q000097:blood
chemical_list: D053318:Apolipoprotein E3; D053327:Apolipoprotein E4; D001057:Apolipoproteins E; D002914:Chylomicrons; D004041:Dietary Fats; D004043:Dietary Fiber; D014280:Triglycerides; D002784:Cholesterol