title: Increasing the viscosity of oat β-glucan beverages by reducing solution volume does not reduce glycaemic responses.
abstract: The soluble fibre (1 → 3)(1 → 4)-β-D-glucan attenuates postprandial glycaemic responses when administered in solution. This attenuating effect is strengthened when solution viscosity is increased by increasing the β-glucan dose or molecular weight (MW). The effect of varying solution viscosity by changing solution volume, without changing the β-glucan dose or MW, on glycaemic responses was determined. A total of fifteen healthy subjects received six 50 g oral glucose beverages prepared with or without 4 g of high-MW (HMW, 580,000 g/mol) or low-MW (LMW, 145,000 g/mol) β-glucan, with a beverage volume of 250 or 600 ml. Postprandial plasma glucose concentration was measured over 2 h, and the peak blood glucose rise (PBGR) and the incremental area under the glycaemic response curve (AUC) were calculated. Subjects served as their own controls. The physico-chemical properties of the beverages were measured to examine their relationship with glycaemic response results. The HMW β-glucan beverage was more viscous and achieved greater reductions in PBGR than the glucose beverage with LMW β-glucan (P < 0·05). At the same MW, the 250 and 600 ml β-glucan beverages differed in viscosity (>9-fold difference) but not in PBGR (P > 0·05). No differences in AUC were detected among the beverages (P = 0·147). The effects of β-glucan on glycaemic response were altered by changes in beverage viscosity achieved through changes in MW but not in volume. Therefore, β-glucan dose and MW are the most vital characteristics for optimising the bioactivity of β-glucan solutions with respect to glycaemic response.
authors.affiliation: Department of Nutritional Sciences, University of Toronto, 150 College Street, Toronto, ON, Canada M5S 3E2.
authors.forename: Melissa G Y
authors.initials: MG
authors.lastname: Kwong
authors.forename: Thomas M S
authors.initials: TM
authors.lastname: Wolever
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Brummer
authors.forename: Susan M
authors.initials: SM
authors.lastname: Tosh
mesh_terms: D000284:Administration, Oral; D000328:Adult; D019540:Area Under Curve; D018554:Avena / Q000737:chemistry*; D001628:Beverages; D001786:Blood Glucose / Q000032:analysis* / Q000187:drug effects; D015992:Body Mass Index; D004043:Dietary Fiber; D005260:Female; D006801:Humans; D007328:Insulin / Q000032:analysis; D008297:Male; D008970:Molecular Weight; D019518:Postprandial Period; D014783:Viscosity; D047071:beta-Glucans / Q000737:chemistry*
chemical_list: D001786:Blood Glucose; D004043:Dietary Fiber; D007328:Insulin; D047071:beta-Glucans; C067858:beta-glucan, (1-3)(1-4)-