Beta-glucan
Two meta-analyses found oat beta-glucan at about 3 g a day or more lowered LDL cholesterol by 0.19 to 0.25 mmol/L. Barley beta-glucan lowered it by 0.25 mmol/L. Adding oat beta-glucan to meals cut the blood sugar rise by 23%. Yeast beta-glucan trials reported fewer colds, but most were small, industry-sponsored and incompletely reported for safety.
Add to Bio HackChecked 2026-11-09
- Status
- Sold as a dietary supplement and food ingredient in the US. FDA allows a health claim linking 3 g a day or more of beta-glucan soluble fiber from whole oats or barley to reduced risk of coronary heart disease.
- Also called
- β-glucan, oat beta-glucan, barley beta-glucan, oat bran, cereal beta-glucan, yeast beta-glucan, beta-1,3/1,6-glucan, Saccharomyces cerevisiae glucan, Wellmune, Yestimun, mushroom beta-glucan
- Taken for
- cholesterol, heart health, blood sugar, weight loss, immunity, colds, upper respiratory infections, allergies
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help5
- StrongShown to lower LDL by about 0.2 to 0.25 mmol/L in adults at 3 g a day or more of oat beta-glucan.
- ModerateShown to lower LDL by about 0.25 mmol/L in adults on a median 6.5 g a day of barley beta-glucan.
- ModerateShown to cut the blood sugar rise after a carbohydrate meal by 23% when oat beta-glucan is added, only at higher molecular weights. These were single-meal tests.
- ModerateShown to lower systolic blood pressure by about 1.4 mmHg in adults with overweight or obesity. Diastolic pressure did not change.
- ModerateShown to lower the odds of colds and shorten them in healthy people taking yeast beta-glucan, across few trials with high heterogeneity.
Reported risks1
- ModerateOnly half of 30 trials of commercial beta-glucan products reported safety data, and only five were registered.How often is not known
What people take it for, and what was found
Shown to help5
LDL cholesterol (oat beta-glucan)
Shown to lower LDL by about 0.2 to 0.25 mmol/L in adults at 3 g a day or more of oat beta-glucan.
The numbers and sources
- Effect
- In 28 trials, 3 g a day or more of oat beta-glucan lowered LDL by 0.25 mmol/L (95% CI 0.20 to 0.30) and total cholesterol by 0.30 mmol/L, with no change in HDL or triglycerides. Dose (3.0 to 12.4 g a day) and duration (2 to 12 weeks) did not change the result [1]. In 58 trials (3,974 people), a median 3.5 g a day lowered LDL by 0.19 mmol/L (95% CI 0.14 to 0.23), non-HDL by 0.20 mmol/L and apoB by 0.03 g/L [2].
- Population
- Adults, mostly with normal to raised cholesterol [1][2].
- Sources
- [1], [2]
- Caveats
- LDL heterogeneity was high in [2] (I² 79%). [1] was supported by DSM Nutritional Products and searched in-house reports at CreaNutrition, a subsidiary of an oat fiber company. FDA's health claim rests on 3 g a day or more from whole oats or barley [3].
LDL cholesterol (barley beta-glucan)
Shown to lower LDL by about 0.25 mmol/L in adults on a median 6.5 g a day of barley beta-glucan.
The numbers and sources
- Effect
- In 14 trials (615 people), a median 6.5 g a day of barley beta-glucan for 4 weeks lowered LDL by 0.25 mmol/L (95% CI 0.20 to 0.30) and non-HDL by 0.31 mmol/L. ApoB did not change [4].
- Population
- Adults in trials of 3 weeks or longer [4].
- Sources
- [4]
- Caveats
- Non-HDL heterogeneity was high (I² 98%) [4].
Blood sugar after meals
Shown to cut the blood sugar rise after a carbohydrate meal by 23% when oat beta-glucan is added, only at higher molecular weights. These were single-meal tests.
The numbers and sources
- Effect
- Across 103 trial comparisons (538 people), adding oat beta-glucan to carbohydrate meals cut the glucose rise (area under the curve) by 23% and the glucose peak by 28%. Insulin fell by 22%. Effects grew with dose and appeared only at molecular weights above 300 kg/mol. Results were similar with and without diabetes [5].
- Population
- Acute crossover feeding trials [5].
- Sources
- [5]
- Caveats
- Single-meal tests, not long-term blood sugar control. Two authors were employees of INQUIS Clinical Research, and 28 of the comparisons were industry funded [5].
Blood pressure
Shown to lower systolic blood pressure by about 1.4 mmHg in adults with overweight or obesity. Diastolic pressure did not change.
The numbers and sources
- Effect
- In people with a BMI of 25 or more, oat beta-glucan lowered systolic blood pressure by 1.38 mmHg (95% CI 0.09 to 2.66). Diastolic blood pressure did not change. Across cereal beta-glucan, total cholesterol fell by 0.24 mmol/L and LDL by 0.19 mmol/L [8].
- Population
- 49 studies, 3,854 people with overweight or obesity [8].
- Sources
- [8]
- Caveats
- One meta-analysis. One author is affiliated with a food science company [8].
Colds and upper respiratory infections (yeast beta-glucan)
Shown to lower the odds of colds and shorten them in healthy people taking yeast beta-glucan, across few trials with high heterogeneity.
The numbers and sources
- Effect
- In 13 trials in healthy people, yeast beta-glucan lowered the odds of an upper respiratory infection (OR 0.345, 95% CI 0.192 to 0.620), the number of episodes (SMD -0.315) and their duration (SMD -0.312) compared with placebo [9]. A review of 34 trials of fungal beta-glucans at 2.5 to 1,000 mg a day for up to 6.5 months reported fewer respiratory infection symptoms, but immune cell and molecular findings were inconsistent [10].
- Population
- Healthy subjects [9]. Healthy people and patients [10].
- Sources
- [9], [10]
- Caveats
- Heterogeneity was high and the trials were few [9]. A review of commercial beta-glucan products found an average of 33 participants per arm, and more than half of trials that reported funding were sponsored by beta-glucan producers [11].
Mixed results1
Body weight
Mixed results: one review found weight about 0.8 kg lower, and a later, larger review in adults with overweight found no change.
The numbers and sources
- Effect
- In 20 trials, cereal beta-glucan lowered body weight by 0.77 kg (95% CI 0.04 to 1.49) and BMI by 0.62. Waist circumference and energy intake did not change [7].
- Population
- Adults in randomized trials [7].
- Sources
- [7]
- Caveats
- A small average change. A later meta-analysis of 49 studies (3,854 people) with a BMI of 25 or more found no change in body weight [8].
Not shown to help1
Long-term blood sugar (HbA1c)
One trial found 6 g a day of oat beta-glucan in bread did not change HbA1c over 16 weeks in adults at risk of type 2 diabetes.
The numbers and sources
- Effect
- In 194 adults at risk of type 2 diabetes, bread enriched to 6 g of oat beta-glucan a day for 16 weeks did not change HbA1c compared with whole-grain wheat bread (difference -0.01%, 95% CI -0.03 to 0.06). Fasting glucose, insulin and LDL cholesterol (-0.11 mmol/L, 95% CI -0.27 to 0.05) did not differ either [6].
- Population
- Adults aged about 58 with a mean BMI of 32 in Germany, Norway and Sweden [6].
- Sources
- [6]
- Caveats
- One trial, run as an effectiveness trial in real-life conditions, against whole-grain wheat bread, not a fiber-free control [6].
Doses studied
Cholesterol trials used 3 to 12.4 g a day of oat beta-glucan [1], with a median of 3.5 g [2], and a median of 6.5 g a day of barley beta-glucan [4]. FDA's claim requires at least 0.75 g per serving [3]. Fungal beta-glucan trials used 2.5 to 1,000 mg a day [10].
Risks
Reported risks1
Incomplete safety reporting
Only half of 30 trials of commercial beta-glucan products reported safety data, and only five were registered.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Of 30 trials of commercial oral and inhaled beta-glucan products, only half reported safety data. Of 105 outcome measures, three were judged clinically relevant, and only five trials were registered [11].
- Population
- 30 randomized trials in healthy or ill participants [11].
- Sources
- [11]
- Caveats
- The review had no outside funding [11]. The absence of reported harm in trials that did not report safety is not evidence of no harm.
Checked, no increase found1
Adverse events in fungal and yeast beta-glucan trials
No adverse event was linked to fungal or yeast beta-glucan in small, short trials of up to 6.5 months.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- A review of 34 trials recorded no adverse event causally related to fungal beta-glucans [10]. A meta-analysis of 13 yeast beta-glucan trials described it as well tolerated [9].
- Population
- Trials of up to 6.5 months [9][10].
- Sources
- [10], [9]
- Caveats
- Trials were small and short.
Claims tested and not found
Sources
- Whitehead A, Beck EJ, Tosh S, et al. Cholesterol-lowering effects of oat β-glucan: a meta-analysis of randomized controlled trials. The American Journal of Clinical Nutrition. 2014. https://doi.org/10.3945/ajcn.114.086108
- 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. https://doi.org/10.1017/s000711451600341x
- U.S. Code of Federal Regulations. 21 CFR 101.81, Health claims: soluble fiber from certain foods and risk of coronary heart disease (CHD). 2024. https://www.govinfo.gov/content/pkg/CFR-2024-title21-vol2/pdf/CFR-2024-title21-vol2-sec101-81.pdf
- 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 reduction. European Journal of Clinical Nutrition. 2016. https://doi.org/10.1038/ejcn.2016.89
- Zurbau A, Noronha JC, Khan TA, et al. The effect of oat β-glucan on postprandial blood glucose and insulin responses: a systematic review and meta-analysis. European Journal of Clinical Nutrition. 2021. https://doi.org/10.1038/s41430-021-00875-9
- Hjorth T, Schadow A, Revheim I, et al. Effectiveness of regular oat β-glucan-enriched bread compared with whole-grain wheat bread on long-term glycemic control in adults at risk of type 2 diabetes: a randomized controlled trial. The American Journal of Clinical Nutrition. 2025. https://doi.org/10.1016/j.ajcnut.2025.06.018
- Rahmani J, Miri A, Černevičiūtė R, et al. Effects of cereal beta-glucan consumption on body weight, body mass index, waist circumference and total energy intake: A meta-analysis of randomized controlled trials. Complementary Therapies in Medicine. 2019. https://doi.org/10.1016/j.ctim.2019.01.018
- Zheng R, Zhang H, Hua H, et al. Cereal beta-glucan and cardiovascular disease risk reduction in overweight and obese populations: a systematic review and meta-analysis of lipid, blood pressure, and anthropometric parameters. Food & Function. 2026. https://doi.org/10.1039/d5fo03598h
- Zhong K, Liu Z, Lu Y, et al. Effects of yeast β-glucans for the prevention and treatment of upper respiratory tract infection in healthy subjects: a systematic review and meta-analysis. European Journal of Nutrition. 2021. https://doi.org/10.1007/s00394-021-02566-4
- Vlassopoulou M, Yannakoulia M, Pletsa V, et al. Effects of fungal beta-glucans on health: a systematic review of randomized controlled trials. Food & Function. 2021. https://doi.org/10.1039/d1fo00122a
- Markovina N, Banjari I, Bucevic Popovic V, et al. Efficacy and safety of oral and inhalation commercial beta-glucan products: Systematic review of randomized controlled trials. Clinical Nutrition. 2020. https://doi.org/10.1016/j.clnu.2019.01.003