An extract from oats known as oat gum (OG) is composed mainly of the polysaccharide (1 + 3) (1 + 4)-/?--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 doseresponse 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 loglviscosity] of the mixtures consumed and the glucose and insulin responses. The relationship shows that 7S96 YO of the changes in plasma glucose and insulin are attributable to viscosity, and that changes occur at relatively low doses and viscosities.

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The aim of the current study was to characterize the effects of isolated and native sources of beta-glucan, oat gum, and oat bran, respectively, when incorporated into a complete meal. Fasting control subjects and subjects with Type 2 diabetes were fed porridge meals containing either wheat farina, wheat farina plus oat gum or oat bran. Blood samples were collected for 3 h after the test meals and plasma glucose and insulin were measured. Oat bran and wheat farina plus oat gum meals reduced the postprandial plasma glucose excursions and insulin levels when compared with the control wheat farina meal in both control and Type 2 diabetic subjects. This study shows that both the native cell wall fibre of oat bran and isolated oat gum, when incorporated into a meal, act similarly by lowering postprandial plasma glucose and insulin levels. A diet rich in beta-glucan may therefore be of benefit in the regulation of postprandial plasma glucose levels in subjects with Type 2 diabetes.

Foods containing soluble dietary fibers delay glucose absorption and lower postprandial plasma glucose. This effect of oat bran has been attributed to oat gum (80% beta-glucan). However, purified oat gum has previously not been available for human studies. In this study the glucose and insulin responses to consuming 14.5 g of specifically prepared oat gum with 50 g glucose were compared with the response to guar gum with glucose and to glucose alone in nine healthy, fasting subjects. Plasma glucose and insulin increases after the glucose drink were greater than after both gum meals between 20 and 60 min (P less than 0.01). The responses to the two gum meals were nearly identical. These results establish that the more palatable oat gum lowers postprandial plasma glucose and insulin concentrations in humans and may be comparable with or of greater benefit than guar gum.