title: Mechanisms underlying the cholesterol-lowering properties of soluble dietary fibre polysaccharides.
abstract: A number of studies have shown a positive relationship between diets rich in soluble dietary fibres (SDF) such as β-glucan, pectin, guar gum and psyllium, and reduced serum cholesterol and thus a decreased risk of cardiovascular disease (CVD). Three major biological mechanisms have been proposed to explain the cholesterol-reducing effects of SDF: prevention of bile salt (BS) re-absorption from the small intestine leading to an excess faecal BS excretion; reduced glycemic response leading to lower insulin stimulation of hepatic cholesterol synthesis; and physiological effects of fermentation products of SDF, mainly propionate. Evidence for the latter mechanism is inconclusive, whereas in vivo, ex vivo and in vitro experiments suggest that BS micelles "bind" to SDF preventing their re-absorption. Whereas, glycemic responses to SDF have been studied extensively, the nature of interactions between bile salt micelles and SDF that lead to incomplete BS re-absorption are poorly defined. Three potential physicochemical mechanisms are proposed together with suggestions for in vitro experiments to test them.
authors.affiliation: Centre for Nutrition and Food Sciences, The University of Queensland, Hartley Teakle Building, St Lucia, Queensland 4072, Australia.
authors.forename: Purnima
authors.initials: P
authors.lastname: Gunness
authors.forename: Michael John
authors.initials: MJ
authors.lastname: Gidley
mesh_terms: D000924:Anticholesteremic Agents / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000378:metabolism*; D004043:Dietary Fiber / Q000378:metabolism*; D005260:Female; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology*; D008297:Male; D011134:Polysaccharides / Q000378:metabolism*; D012995:Solubility
chemical_list: D000924:Anticholesteremic Agents; D001647:Bile Acids and Salts; D004043:Dietary Fiber; D011134:Polysaccharides