title: Glucose and insulin do not decrease in a dose-dependent manner after increasing doses of mixed fibers that are consumed in muffins for breakfast.
abstract: Conventional wisdom suggests that fiber consumption leads to lower postprandial glucose and insulin response. We hypothesized that increasing doses of mixed, viscous fiber would lower glucose and insulin levels in a dose-dependent manner. Healthy men (n = 10) and women (n = 10) with a body mass index of 24 ± 2 (mean ± SEM) participated in this double-blind, crossover study. On 4 separate visits, fasting subjects consumed an approximately 2093 kJ (500 calorie) muffin with 0, 4, 8, or 12 g of mixed fibers. Blood was drawn to measure glucose and insulin at regular intervals throughout a 3-hour test period. Area under the curve (AUC) glucose was significantly lower after 0 g of fiber than after 4, 8, or 12 g of fiber (arbitrary AUC units ± SEM: 25.3 ± 5.2 vs 44.6 ± 7.7, 49.7 ± 7.9, 51.5 ± 6.6, respectively; P < .006). Area under the curve glucose increased with increasing fiber doses (P for trend = .0003). Area under the curve insulin was higher after the 4-g dose than after the 0-, 8-, and 12-g doses (arbitrary AUC units ± SEM: 84.4 ± 8.0 vs 60.1 ± 6.5, 69.4 ± 8.7, 69.7 ± 8.5, respectively; P < .05); it did not change in a dose-dependent manner. Area under the curve glucose and AUC insulin did not correlate with each other. Glucose and insulin did not decrease in a dose-dependent manner after 0, 4, 8, and 12 g of mixed fibers were consumed in muffins for breakfast. The lack of differences was largely based on the individual variation in glucose response. Caution should be used when making general claims about the expected impact of fiber on glucose and insulin levels.
authors.affiliation: Department of Food Science and Nutrition, University of Minnesota, St Paul, MN 55108, USA.
authors.forename: Holly J
authors.initials: HJ
authors.lastname: Willis
authors.forename: William
authors.initials: W
authors.lastname: Thomas
authors.forename: Alison L
authors.initials: AL
authors.lastname: Eldridge
authors.forename: Laura
authors.initials: L
authors.lastname: Harkness
authors.forename: Hilary
authors.initials: H
authors.lastname: Green
authors.forename: Joanne L
authors.initials: JL
authors.lastname: Slavin
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D015992:Body Mass Index; D018592:Cross-Over Studies; D004043:Dietary Fiber / Q000008:administration & dosage*; D004311:Double-Blind Method; D002149:Energy Intake; D005260:Female; D005527:Food, Fortified; D038321:Glycemic Index; D006801:Humans; D007328:Insulin / Q000097:blood*; D016014:Linear Models; D008297:Male; D019518:Postprandial Period; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D004043:Dietary Fiber; D007328:Insulin