Oats & barley

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The evidence

• In 2014, a meta-analysis of 28 RCTs showed that a minimum of 3g of oat beta-glucans per day reduced LDL cholesterol by 0.25mmol/L – a 6% decrease compared to control groups⁹.

• Two years later, a 2016 meta-analysis of 14 RCTs with 615 participants found a 0.25mmol/L drop in LDL cholesterol and a 0.31mmol/L decrease in non HDL cholesterol among those who ate 1.5g-12g daily of barley beta-glucan for four weeks¹⁶. 
• A more comprehensive meta-analysis in 2016 analysed 58 RCTs with 3,974 participants who were given a daily dose of 3.5g of oat beta-glucan. The results showed significant reductions in LDL cholesterol (4.2%), non-HDL cholesterol (4.8%) and Apolipoprotein B (2.3%)¹⁰.
• In 2023, a systematic review of 17 RCTs affirmed the previous findings, showing that a daily intake of approximately 3g of oat beta-glucans substantially lowered both total and LDL cholesterol levels¹⁸. This review also noted a triglyceride-reducing effect, especially among individuals who were overweight, had diabetes or had metabolic syndrome.

Proposed mechanism

The hypothesised cholesterol-lowering mechanism revolves around the ability of beta-glucans to interfere with the bile acid metabolism^19,20.

• Beta-glucans form a gel-like substance in the gut lumen which can bind to dietary cholesterol and bile acids which contain recycled cholesterol.
• The binding of beta-glucans to bile acids results in the formation of complexes that are less readily absorbed from the small intestine and instead excreted through faeces, removing cholesterol from the body.
• As some bile acids are excreted rather than re-absorbed, the liver has to produce new bile acid. In order to do this, the liver removes cholesterol circulating in the blood, thus helping to reduce blood cholesterol levels.

Additionally, beta-glucans may have a prebiotic effect, positively influencing gut bacteria which produce short-chain fatty acids (SCFA). SCFA can interfere with cholesterol metabolism and production²⁰.

As the proposed mechanism differs from statin pathways, beta-glucans would further reduce serum cholesterol levels alongside statin therapy.

Effective dose: 3g beta-glucans daily

Achieving 3g a day  with oats and barley 

Choose any three of the following servings each day. Each of the following single servings contain around 1g of beta-glucan.

Food	Single serve	How to achieve it
Porridge oats – one of the UK’s favourite breakfasts	30g oats	Serve as porridge or overnight oats Use them to make home-made oat bars or in fruit crumble toppings
Oat-based breakfast cereal flakes	30-35g bowl	Check the label, they must be 100% oat-based
Oat cakes – reduced salt	3 oatcakes	A great snack – choose reduced salt varieties
Pearl barley	75g cooked or 25-30g raw	Can be used as an alternative carbohydrate to accompany meals instead of potatoes, rice or pasta Great to thicken stews and soups Use as a salad base
Oat bran	1-2 tbsp	Sprinkle over main meals such as stews, soups, curries or porridge

References 

1. Sima P, Vannucci L, Vetvicka V. β-glucans and cholesterol (Review). Int J Mol Med. 2018;41(4):1799-1808. doi:10.3892/ijmm.2018.3411
2. Whitehead A, Beck EJ, Tosh S, Wolever TM. Cholesterol-lowering effects of oat β-glucan: a meta-analysis of randomized controlled trials1234. The American Journal of Clinical Nutrition. 2014;100(6):1413-1421. doi:10.3945/ajcn.114.086108
3. FDA. 21 CFR Part 101.81 - Health Claims: Soluble fibre from certain foods and risk of coronary heart disease (CHD). Accessed October 12, 2023. https://www.ecfr.gov/current/title-21/part-101#101.81
4. European Commission. Commission Regulation (EU) No 1048/2012 of 8 November 2012 on the authorisation of a health claim made on foods and referring to the reduction of disease risk - Barley beta-glucan. OJ L. 2012;310:38-40.
5. European Commission. Commission Regulation (EU) No 1160/2011 of 14 November 2011 on the authorisation and refusal of authorisation of certain health claims made on foods and referring to the reduction of disease risk (Oat beta-glucan). OJ L. 2011;296:26-28.
6. Tiwari U, Cummins E. Meta-analysis of the effect of β-glucan intake on blood cholesterol and glucose levels. Nutrition. 2011;27(10):1008-1016. doi:10.1016/j.nut.2010.11.006
7. Ho HVT, Sievenpiper JL, Zurbau A, et al. The effect of oat β-glucan on LDL-cholesterol, non-HDL-cholesterol and apoB for CVD risk reduction: a systematic review and meta-analysis of randomised-controlled trials. British Journal of Nutrition. 2016;116(8):1369-1382. doi:10.1017/S000711451600341X
8. Ho HVT, Sievenpiper JL, Zurbau A, et al. A systematic review and meta-analysis of randomized controlled trials of the effect of barley β-glucan on LDL-C, non-HDL-C and apoB for cardiovascular disease risk reductioni-iv. Eur J Clin Nutr. 2016;70(11):1239-1245. doi:10.1038/ejcn.2016.89
9. Yu J, Xia J, Yang C, et al. Effects of Oat Beta-Glucan Intake on Lipid Profiles in Hypercholesterolemic Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients. 2022;14(10):2043. doi:10.3390/nu14102043
10. Amerizadeh A, Ghaheh HS, Vaseghi G, Farajzadegan Z, Asgary S. Effect of Oat (Avena sativa L.) Consumption on Lipid Profile With Focus on Triglycerides and High-density Lipoprotein Cholesterol (HDL-C): An Updated Systematic Review. Current Problems in Cardiology. 2023;48(7):101153. doi:10.1016/j.cpcardiol.2022.101153
11. Wang Y, Harding SV, Thandapilly SJ, Tosh SM, Jones PJH, Ames NP. Barley β-glucan reduces blood cholesterol levels via interrupting bile acid metabolism. British Journal of Nutrition. 2017;118(10):822-829. doi:10.1017/S0007114517002835
12. Joyce SA, Kamil A, Fleige L, Gahan CGM. The Cholesterol-Lowering Effect of Oats and Oat Beta Glucan: Modes of Action and Potential Role of Bile Acids and the Microbiome. Front Nutr. 2019;6:171. doi:10.3389/fnut.2019.00171

Published: June 2024