The amazing oat fibre, beta glucan, has been shown to lower cholesterol. In fact, consuming at least 3g of oat beta glucan daily can significantly lower cholesterol, and people with higher cholesterol levels experience higher absolute falls (1,2,3,4).
Health claims for (oat) beta glucan have been approved worldwide, including the United States, Canada, Europe, Malaysia, Australia and New Zealand (5,6,7,8,9,10).
The governing legislation in the UK is the European Food Safety Authority (EFSA). In 2009, EFSA approved the general function claim (article 13.1) that regular consumption of beta glucan contributes to maintenance of normal blood cholesterol concentrations, for foods providing at least 3g of beta glucan per day (7).
In 2010, EFSA approved the disease risk reduction claim (article 14) that oat beta glucan has been shown to lower/reduce blood cholesterol. Blood cholesterol lowering may reduce the risk of (coronary) heart disease, for foods providing at least 3g of oat beta glucan per day. As a result, 3g has become the suggested daily intake. However, even 1g of oat beta glucan daily can be expected to give a small cholesterol lowering effect (8).
Soluble (or viscous) fibres (like oat beta glucan) now feature in International and UK recommendations for the management of dyslipidaemia (11,12).
Additionally, studies suggest that oat consumption providing at least 3g beta glucan daily could be expected to offer reductions in total and LDL-cholesterol in the region of 5 % (1).
While the exact mechanism by which oats lower cholesterol is unknown, the widely proposed main mechanism of action is the disruption of the enterohepatic circulation.
As part of normal digestion, oat beta glucan, a soluble fibre, dissolves to create a highly viscous, gum-like gel in the gut. This reduces the absorption of cholesterol-rich bile acids and dietary cholesterol, excreting them in the faeces. To compensate for this increased excretion, the production of new bile acid is promoted, resulting in a lowering of cholesterol in the blood (13). See figure 1.
Other proposed mechanisms of action by which oat beta glucan may lower cholesterol include inhibiting cholesterol uptake in the intestinal wall, and bacterial fermentation of the beta glucan causing the release of short-chain fatty acids that may reduce cholesterol synthesis through inhibition of the enzyme HMG-CoA reductase.
Oat beta glucan reduces total cholesterol and LDL-cholesterol without affecting HDL-cholesterol (14,15,16).
Figure 1: Enterohepatic Circulation - this is disrupted by beta glucan reducing bile reabsorption and increasing faecal losses. More cholesterol is then taken from the circulation to replace the lost bile.
1. Whitehead A, et al. Cholesterol-lowering effects of oat beta-glucan: a meta-analysis of randomised controlled trials. Am J Clin Nutr. 2014; 100:1413-21.
2. SACN. Carbohydrates and Health. 2015. https://www.gov.uk/government/publications/sacn-carbohydrates-and-health-report. Accessed February 2019.
3. Othman RA, et al. Cholesterol-lowering effects of oat β-glucan. Nutr Rev. 2011 Jun;69(6):299-309.
4. Ruxton CHS, Derbyshire E A. A systematic review of the association between cardiovascular risk factors and regular consumption of oats. Br Food J. 2008;110:1119-1132.
5. US Department of Health and Human Services, Food and Drug Administration. Food Labeling:Health claims; Oats and Coronary Heart Disease—final rule. Fed Regist. 1997;62:3584-3601.
6. Bureau of Nutritional Sciences FD, Health Products and Food Branch, Health Canada. . Oat products and blood cholesterol lowering: summary of assessment of a health claim about oat products and blood cholesterol lowering. 2010. www.hc-sc.gc.ca/fn-an/label-etiquet/claims-reclam/assess-evalu/oat-avoine-eng.php. Accessed February 2019.
7. European Food Safety Authority. Scientific Opinion on the substantiation of health claims related to beta glucans and maintenance of normal blood cholesterol concentrations. EFSA Journal. 2009;7(9):1254.
8. European Food Safety Authority. Panel on Dietetic Products, Nutrition and Allergies (NDA);Scientific Opinion on the substantiation of a health claim related to oat beta-glucan and lowering blood cholesterol and reduced risk of (coronary) heart disease pursuant to Article 14 of Regulation (EC) No 1924/2006. EFSA Journal. 2010;8(12):1885.
9. Malaysia MoH. Malaysian dietary guidelines—Key Message 14—make effective use of nutrition information on food labels (Appendix 4). 2010.
10. Food Standards Australia and New Zealand. Standard 1.2.7: Nutrition, health and related claims. Food Standards Gazette. 2013;80.
11. International Atherosclerosis Society.An International Atherosclerosis Society Position Paper: Global Recommendations for the Management ofDyslipidemia. 2013; Full Report.
12. Joint British Societies’ consensus recommendations for the prevention of cardiovascular disease. Heart. 2014;100: ii1–ii67.
13. Main L. Oats and Oat Products in Cholesterol Lowering Diets. Complete Nutrition. Dec/Jan 2015;15 (6):63-65.
14. Theuwissen E, Mensink RP. Water-soluble dietary fibers and cardiovascular disease. Physiol Behav. 2008 May 23;94(2):285-292.
15. Chen J, et al. The role of molecular weight and viscosity of oat β-glucan in hypocholesterolemic effect. Am J Clin Nutr. 2010;92:1538.
16. Queenan KM, et al. Concentrated oat beta-glucan, a fermentable fiber, lowers serum cholesterol in hypercholesterolemic adults in a randomized controlled trial. Nutr J. 2007 Mar 26;6:6.