Beta-1,3/1,6-D-glucan (yeast or oat)

Polysaccharide immunomodulator. Oat beta-glucan is a dietary fibre with EFSA-approved cholesterol health claim. Yeast beta-glucan (Wellmune) is a supplement with immunity marketing without EFSA approval

ATC code: A11JA-BETA-GLUCAN

Brand names – supplements: Now Beta-Glucan, Wellmune, Solgar Beta Glucans, Swanson Beta-GlucanSupplements are not tested in clinical trials and are not registered as medications.

Updated 24 Sep 2026 · Methodology

Indications

Primary hypercholesterolemia

Adjunct

Oat beta-glucan is one of the few supplements with an -approved cardiovascular risk health claim. Meta-analyses of RCTs (Whitehead 2014, AbuMweis 2010) showed that 3 g/day oat beta-glucan for 4–12 weeks lowers total cholesterol by 0.30 mmol/L and by 0.25 mmol/L in mild-to-moderate hypercholesterolaemia. EFSA 2010 approved the official health claim: «consumption of 3 g/day oat beta-glucan lowers blood cholesterol; lowering cholesterol reduces coronary heart disease risk». 2019 list dietary fibres (including oat beta-glucan) as adjunctive non-pharmacological measure in dyslipidaemia – one serving of oatmeal per day provides ≈3–4 g beta-glucan. Does not replace statins in high or very-high cardiovascular risk (T2DM, prior MI, stroke, familial hypercholesterolaemia). In primary hypercholesterolaemia with LDL ≥4.9 mmol/L or high -OP atorvastatin or rosuvastatin with ezetimibe remain first-line, with PCSK9 inhibitors as add-on.

Sources

ICD-10: E78.0 · ICD-11: 5C80.00

Marketing claims without evidence base

The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.

Cancer prevention through supplements

Not recommended

Beta-1,3/1,6-D-glucan is a polysaccharide from yeast cell walls or from oats, sold as an immune supplement and marketed for cancer prevention. There is no solid evidence for this use: the available data do not show that taking this supplement lowers cancer risk. What actually reduces that risk are other measures – not smoking, limiting alcohol, keeping a healthy weight, HPV and hepatitis B vaccination, and age-appropriate screening. This supplement should not replace approaches with proven benefit, or you may miss the care or testing you actually need.

Sources

Chronic fatigue

Not recommended

Beta-1,3/1,6-D-glucan is a polysaccharide from the cell wall of baker's yeast or from oats. Supplements market it for chronic fatigue and immune support. For chronic fatigue, beta-glucan has not shown convincing benefit, and there is no good clinical evidence for this use. Persistent fatigue calls for finding the cause (anemia, hypothyroidism, iron or B12 deficiency, sleep problems, depression) and treating that. Beta-glucan is harmless here, but it should not replace treatment your doctor has chosen, since that can mean missing a condition that does respond to therapy.

Sources

NICE: Myalgic encephalomyelitis (or encephalopathy)/chronic fatigue syndrome: diagnosis and management (NG206) (2021)

ICD-10: R53 · ICD-11: MG22

Common cold

Not recommended

Yeast beta-glucan is sold as a «natural cold remedy» promising symptom duration and severity reduction. Talbott 2009 and Auinger 2013 RCTs showed moderate cold symptom reduction with Wellmune 250 mg/day, but the effect did not exceed clinically significant threshold and depended on population (marathoners, healthy volunteers, not patients with active cold). 2013 and 2014 rejected the health claim. No Cochrane systematic review on beta-glucan in the common cold. AAFP 2019 and SEIMC 2020 for the common cold list symptomatic therapy first-line (paracetamol, nasal irrigation, rest, fluids); beta-glucan is not mentioned. If beta-glucan was recommended as a substitute for symptomatic therapy or antibiotic in bacterial superinfection, consider seeking a second opinion.

Sources

ICD-10: J00 · ICD-11: CA00

Immune support and respiratory infection care

Not recommended

Yeast beta-glucan (Wellmune, Saccharomyces cerevisiae) is widely sold as a «natural immunomodulator» promising URI frequency reduction and cold symptom relief. Small RCTs Talbott 2009 in 75 post-marathon athletes and Auinger 2013 in 100 healthy volunteers showed moderate URI frequency and severity reduction with Wellmune 250 mg/day × 12 weeks. Evidence quality is limited by small samples, single-centre design and potential conflict of interest (sponsored by manufacturer). 2013 reviewed the «yeast beta-glucan helps to maintain body's defence against pathogens» claim and rejected it due to insufficient data. EFSA 2014 rejected again. AAFP 2019 and SEIMC 2020 for the common cold list symptomatic therapy first-line; beta-glucan is not in international guidelines. Oat beta-glucan as dietary fibre is not related to immune claims.

Sources

How to read tiers A–F

AStrong evidence – first or second line in international guidelines
BRecommended in selected cases
CStudy data contradict each other
DBenefit not proven, no documented harm
FDocumented harm, or risk without benefit

Mechanism of action

Beta-glucans are polysaccharides made of D-glucose monomers linked by beta-1,3 and beta-1,6 bonds. Sources: baker's yeast cell walls (Saccharomyces cerevisiae), cereals (oat, barley), mushrooms (reishi, shiitake, maitake). Oat beta-glucan is a soluble dietary fibre: binds bile acids in the intestine, increases cholesterol excretion, reduces reabsorption and increases bile acid synthesis from cholesterol in the liver. 2010 approved health claim: «consumption of 3 g oat beta-glucan per day lowers blood cholesterol; lowering cholesterol reduces coronary heart disease risk». Yeast beta-glucan (Wellmune, Kerry Group) binds dectin-1 on macrophages and neutrophils, theoretically activating innate immunity. EFSA 2013 rejected the immune defence health claim for yeast beta-glucan due to insufficient data.

Safety

Contraindications

Active autoimmune disease (SLE, MS, RA) – Th1 immune activation risk
Immunosuppressant therapy (ciclosporin, tacrolimus, methotrexate, biologics)
Yeast allergy (for yeast beta-glucan) or oat/barley allergy (for oat beta-glucan)
Coeliac disease and gluten intolerance when using oat beta-glucan from non-uncontaminated sources
Post-organ transplantation

Serious adverse effects

Allergic reactions in yeast- or grain-hypersensitive patients (rare)
Autoimmune process activation in predisposed patients (theoretical risk)
Delayed statin therapy in high cardiovascular risk patients relying only on beta-glucan

Common adverse effects

Flatulence (especially with oat beta-glucan)
Bloating
Stool habit changes
Nausea (at high doses)

Pregnancy: can you take Beta-1,3/1,6-D-glucan (yeast or oat)?

Oat beta-glucan as part of whole-grain foods is considered safe in pregnancy (part of a normal diet). Isolated yeast beta-glucan supplements in pregnancy have not been studied – avoid.

Breastfeeding: can you take Beta-1,3/1,6-D-glucan (yeast or oat)?

Oat products with beta-glucan are considered safe during breastfeeding (part of a normal diet). Isolated yeast beta-glucan supplements in lactating women have not been studied.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

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Frequently asked

What is Beta-1,3/1,6-D-glucan (yeast or oat) used for?

Beta-1,3/1,6-D-glucan (yeast or oat) is evaluated for the following indications with varying evidence strength: Primary hypercholesterolemia (evidence tier B), Immune support and respiratory infection care (evidence tier D), Common cold (evidence tier D). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Beta-1,3/1,6-D-glucan (yeast or oat)?

Common side effects of Beta-1,3/1,6-D-glucan (yeast or oat) (≥ 1 in 100): Flatulence (especially with oat beta-glucan), Bloating, Stool habit changes, Nausea (at high doses). See the Safety section for uncommon and serious reactions.

Is Beta-1,3/1,6-D-glucan (yeast or oat) safe during pregnancy?

Oat beta-glucan as part of whole-grain foods is considered safe in pregnancy (part of a normal diet). Isolated yeast beta-glucan supplements in pregnancy have not been studied – avoid.

Is Beta-1,3/1,6-D-glucan (yeast or oat) compatible with breastfeeding?

Oat products with beta-glucan are considered safe during breastfeeding (part of a normal diet). Isolated yeast beta-glucan supplements in lactating women have not been studied.

Who should not take Beta-1,3/1,6-D-glucan (yeast or oat)?

Beta-1,3/1,6-D-glucan (yeast or oat) is contraindicated in: Active autoimmune disease (SLE, MS, RA) – Th1 immune activation risk; Immunosuppressant therapy (ciclosporin, tacrolimus, methotrexate, biologics); Yeast allergy (for yeast beta-glucan) or oat/barley allergy (for oat beta-glucan); Coeliac disease and gluten intolerance when using oat beta-glucan from non-uncontaminated sources; Post-organ transplantation. Full list in the Safety section.

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