Item – Theses Canada

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OCLC number
720807586
Link(s) to full text
LAC copy
LAC copy
Author
Breitman, Pearl Laurie,1976-
Title
The effects of viscous dietary fibers on the parameters of appetite and food intake regulation.
Degree
Ph. D. -- University of Toronto, 2009
Publisher
Ottawa : Library and Archives Canada = Bibliothèque et Archives Canada, [2010]
Description
2 microfiches
Notes
Includes bibliographical references.
Abstract
Obesity results in significant morbidity and mortality. Hypocaloric diets lead to hunger, discontinuation of diet and weight re-gain. Soluble dietary fiber may control hunger, however the evidence is inconsistent; possibly from fiber property differences. 'Purpose.' To examine soluble fiber blend (SFB) rheological and gravimetric properties and physiological mechanisms. 'Methods.' Healthy participants arrived fasted and randomly consumed study treatments. Glucose, insulin, growth hormone, acetaminophen (marker of gastric emptying time), symptoms, appetite and food intake were assessed. Treatments: Study 1: Four glucomannan particle sizes; Study 2: Two, 4 or 6g of SFB; Study 3: High (SFB), medium (glucomannan) or low (cellulose) viscosity fibers; Study 4: SFB or cellulose. Studies 3 and 4: food intake and satiety were also assessed at a pizza lunch. All studies used insoluble fiber controls. 'Results.' Study 1: In N=15 (29.5±2.3yrs; BMI:22.1±0.8kg/m2) glucose iAUC was lower (p=0.005) with large (199.6±23.1min.mmol/l) vs. medium (257.7±45.6min.mmol/l) and control (256.9±35.3min.mmol/l) particle sizes. Insulin iAUC was higher (p<0.01) in control (19130.5±3834.0min.pmol/l) vs. all particles. Satiety was greater (p=0.04) after large (-0.27±0.25cm) vs. control (-1.08±0.34cm). Study 2: In N=9(33.4±4.2yrs; BMI:24.4±1.5kg/m 2) glucose was lower (p<0.05) at 15, 30 and 60min with 4 and 6g vs. 2g and control. Glucose iAUC was higher (p=0.0001) in control (341.3±0.34min.mmol/l) vs. all doses. Study 3: N=35 (16.2±0.1yrs; BMI:22.2±3.6kg/m 2) pizza intake was lower (p=0.047) after SFB (264±20g) vs. glucomannan (317±18g). Study 4: N=19 (39.0±2.6yrs; BMI:28.5±0.6kg/m 2), satiety was numerically higher after SFB, however not significantly. Gastric emptying AUC was slower (p=0.004) after control (18330.13±1570.0umol/lmin) vs. SFB (19201.4±1479.5umol/l.min). Glucose and insulin iAUC were lower (p<0.0001) after SFB (125.6±7.9min.mmol/l, 8751.3±3256.4min.pmol/l, respectively) vs. control (181.2±7.8min.mmol/l, 57661.6±3321.4min.pmol/l, respectively). 'Conclusions.' Concentration and rheological variations in viscosity and particle size affected glucose, insulin, appetite and food intake, such that larger particle sizes of glucomannan and highly viscous SFB doses of 4-6g reduced postprandial glucose and insulin and lead to greater reductions in appetite and food intake. Longer term studies are required to further define the dose and viscosities of fiber to consistently reduce appetite and further maintain healthy body weight. The current study suggests that larger particle size and greater than or equal to 4-6g doses of fiber intake may aid in glycemic control.
ISBN
9780494525982
0494525983