British Journal of Nutrition

Metabolic effects of complex carbohydrates

Effect of dose and modification of viscous properties of oat gum on plasma glucose and insulin following an oral glucose load

Peter J.Wooda1, Jan T. Braatena2, Fraser W. Scotta3, K. Doreen Riedela2, Mark S. Wolynetza4 and Maurice W. Collinsa3

a1 Centre for Food and Animal Research, Agriculture and Agri-Food Canada, Ottawa, Ontario KIA 0C6, Canada

a2 Division of Endocrinology and Metabolism, Ottawa Civic Hospital, Ottawa, Ontario K17 4E9, Canada

a3 Nutrition Research Division, Food Directorate, Health Canada, Ottawa, Ontario KIA 0L2, Canada

a4 Research Program Service, Agriculture and Agri-Food Canada, Ottawa, Ontario KIA 0C6, Canada

Abstract

An extract from oats known as oat gum (OG) is composed mainly of the polysaccharide (1→3) (1→4)-β-D-glucan, which is highly viscous in aqueous solution. Viscous polysaccharides are known to attenuate postprandial plasma glucose and insulin responses. The purposes of this study were to determine the dose–response to OG and establish quantitatively the effect of viscosity on plasma glucose and insulin levels of healthy humans consuming 50 g glucose. Increasing the dose of OG successively reduced the plasma glucose and insulin responses relative to a control without gum. Reduction of the viscosity of OG by acid hydrolysis reduced or eliminated the capacity to decrease postprandial glucose and insulin levels. The ability of OG to modify glycaemic response was unchanged following agglomeration in the presence of maltodextrin. Agglomerated gum dispersed smoothly in a drink without formation of lumps, and development of maximum viscosity was delayed. These properties improve palatability. There was a highly significant linear relationship between log[viscosity] of the mixtures consumed and the glucose and insulin responses. The relationship shows that 79–96% of the changes in plasma glucose and insulin are attributable to viscosity, and that changes occur at relatively low doses and viscosities.

(Received October 06 1993)

(Revised January 24 1994)

(Accepted February 15 1994)

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