Dietary fiber and satiety: the effects of oats on satiety

Abstract

This review examines the effect of β-glucan, the viscous soluble fiber in oats, on satiety. A literature search for studies that examined delivery of the fiber in whole foods or as an extract was conducted. Viscosity interferes with the peristaltic mixing process in the small intestine to impede digestion and absorption of nutrients, which precipitates satiety signals. From measurements of the physicochemical and rheological properties of β-glucan, it appears that viscosity plays a key role in modulating satiety. However, the lack of standardized methods to measure viscosity and the inherent nature of appetite make it difficult to pinpoint the reasons for inconsistent results of the effects of oats on satiety. Nevertheless, the majority of the evidence suggests that oat β-glucan has a positive effect on perceptions of satiety.

Keywords: appetite; dietary fiber; oats; satiety; β-glucan.

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Figures

Figure 1

Diagram of the oat caryopsis (with the hull) that has been split longitudinally to display the major fractions of the groats: (A) bran that includes the pericarp, seed coat, nucellus, aleurone layer, and a large portion of the subaleurone layer of the starchy endosperm; (B) starchy endosperm; (C) germ-endosperm interface. Below (C) is a cross-section of the groat diagrammed in (C). Reproduced with permission from Miller and Fulcher.

Figure 2

Oat β-glucan, a linear polysaccharide consisting of 4-O-linked units interrupted by 3-O-linked β-D glucopyranosyl units.