The effects of diets enriched in beta-glucans on blood lipoprotein concentrations
ABSTRACT Dietary beta-glucans lower the blood concentrations of cholesterol in animals and humans. Recent studies have uncovered mechanisms by which dietary beta-glucans may regulate cholesterol homeostasis. There is evidence that beta-glucans sequester bile acids in the intestine, reducing their reabsorption and return to the liver. Reducing hepatic bile acid concentrations activates the enzyme CYP7A1, which converts cholesterol into bile acids. This action leads to a reduction of hepatic cell cholesterol content, which up-regulates low-density lipoprotein (LDL) receptor synthesis and thereby accelerates the transportation of LDL-cholesterol from the blood into hepatocytes. Reduced intracellular cholesterol also up-regulates the hepatic synthesis of 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme in cholesterol synthesis. Statins inhibit 3-hydroxy-3-methylglutaryl coenzyme A reductase and could therefore provide an additive effect in suppressing hepatocyte cholesterol to that produced by enhancing its depletion with beta-glucans. Through this combination of agents, one would expect a greater clearance of LDL from the plasma with lower steady state levels of LDL-cholesterol.
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ABSTRACT: The aim of this study was to evaluate the effect of yacon (Smallanthus sonchifolius)(Poepp.& Endl.) on clinical parameters under diabetic conditions. The aqueous extract of yacon tuberous roots (YRAE; 0.76g fructan kg(-1) body weight) was prepared at the moment of each administration. Thirty-two male rats were divided into four groups (n=8): control group (C); group that received YRAE (Y); untreated diabetic group (DM1); and diabetic group treated with YRAE (Y-DM1). The diabetes mellitus was induced by streptozotocin (60mg kg-1 body weight). The animals from Y2 and Y-DM1 received YRAE by gavage, at 7-day intervals, for 30 days. The aqueous extract of yacon roots decreased (p<0.05) the water and food intake in diabetic rats treated with YRAE (Y-DM1). YRAE treatment reduced (p<0.05) glycaemia, total cholesterol, VLDL, LDL and triacylglycerol levels in diabetic rats (YRAE). HDL, urea and creatinine levels did not differ (p>0.05) between the Y and Y-DM1 groups. YRAE normalised alanine aminotransferase (ALT) activity, when comparing DM1 and Y-DM1 rats, but had no effect on lactate dehydrogenase activity (LDH). In conclusion, YRAE was sufficient for controlling water and food consumption, hyperglycaemia and dyslipidaemia, and promote the reduction of the ALT, suggesting a hepatoprotective effect in rats with STZ-induced DM1.Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 06/2013; 59. DOI:10.1016/j.fct.2013.05.050 · 2.61 Impact Factor
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ABSTRACT: This article presents an overview of the recent advances into the health promoting potentials of oat β‐glucan. Oat β‐glucan (OβG) consists mainly of the linear polysaccharide (1→3), (1→4)‐β‐D‐glucan and is often called β‐glucan. This soluble oat fiber is able to attenuate blood postprandial glycemic and insulinemic responses, to lower blood total cholesterol and low‐density lipoprotein (LDL) cholesterol, and to improve high‐density lipoprotein (HDL) cholesterol and blood lipid profiles as well as to maintain body weight. Thus, OβG intake is beneficial in the prevention, treatment, and control of diabetes and cardiovascular diseases. In addition, OβG can stimulate immune functions by activating monocytes/macrophages and increasing the amounts of immunoglobulin, NK cells, killer T‐cells, and so on, which will improve resistance to cancer and infectious and parasitic diseases, as well as increase biological therapies and their prevention. All these health benefits of OβG may be explained by its physicochemical properties (such as viscosity, molecular weight) which can be affected by extraction methods and its behavior in gastrointestinal tract. Articles documenting these health benefits and effects are reviewed.Comprehensive Reviews in Food Science and Food Safety 07/2012; 11(4). DOI:10.1111/j.1541-4337.2012.00189.x · 3.54 Impact Factor