Increasing the viscosity of oat β-glucan solutions by reducing solution volume does not reduce glycemic responses.

Kwong, M.G.Y., Wolever, T.M.S., Brummer, Y., and Tosh, S.M. (2013). "Increasing the viscosity of oat β-glucan solutions by reducing solution volume does not reduce glycemic responses.", British Journal of Nutrition, 110(8), pp. 1465-1471. doi : 10.1017/S000711451300069X  Access to full text

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.

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