Beta-glucans
Polysaccharides responsible for most of the documented immunomodulatory properties of medicinal mushrooms, oats, and barley — the common denominator behind dozens of species described in this knowledge base.
Number of studies
1
Safety
Moderate
Time to effects
The effect on LDL cholesterol is usually visible after several weeks of regular intake.
Who it's for
Table of contents
TL;DR
Polysaccharides responsible for most of the documented immunomodulatory properties of medicinal mushrooms, oats, and barley — the common denominator behind dozens of species described in this knowledge base.
- →Cereal beta-glucans have an EFSA-recognized LDL cholesterol-lowering effect
- →Mushroom-derived beta-glucans activate innate immune cells in vitro and in animal models
- →Represent a shared, identified mechanism for many traditionally used medicinal mushrooms
| Compound type | Polysaccharide (beta-1,3 and beta-1,6 bonds, or beta-1,3/1,4) |
|---|---|
| Sources | Medicinal mushrooms, yeast, oats, barley |
| Research level | Moderate — strong for the effect of cereal beta-glucans on cholesterol (recognized by EFSA) |
| Form | Naturally in food or as an isolated extract |
| Status | Natural food component, not a drug |
Understand
Overview
Beta-glucans are a group of polysaccharides made of glucose units joined by beta-glycosidic bonds, occurring naturally in the cell walls of mushrooms, yeast, oats, and barley. It's beta-glucans — more precisely, their chemical structure (1,3 and 1,6 bond types) — that account for most of the documented immunomodulatory properties attributed to the medicinal mushrooms described in this knowledge base, from shiitake to lion's mane.
The mechanism of action of mushroom-derived beta-glucans differs significantly from that of oat- and barley-derived ones: the former activate immune cells (macrophages, NK cells) via the dectin-1 receptor, while cereal beta-glucans work mainly by increasing the viscosity of gut contents, which slows the absorption of cholesterol and glucose — hence their documented cholesterol-lowering effect, officially recognized by the European Food Safety Authority.
Who can realistically benefit from this? Understanding beta-glucans as a common denominator helps you evaluate the entries on individual medicinal mushrooms in this knowledge base more critically — rather than treating each species as a separate 'magic' substance, it's worth knowing that many of the properties attributed to them stem from the same class of compounds, present in varying concentrations and structural configurations.
Mechanism of action
Mushroom-derived beta-glucans (type 1,3/1,6) bind to the dectin-1 receptor on the surface of macrophages and other cells of the innate immune system, activating a signaling cascade that leads to enhanced phagocytosis and the production of pro-inflammatory cytokines in a controlled, moderate degree. This activation of the innate immune system underlies the immunomodulatory properties attributed to medicinal mushrooms.
Cereal beta-glucans (oats, barley, type 1,3/1,4), on the other hand, act mainly mechanically in the digestive tract — they increase the viscosity of gut contents, slowing glucose absorption and binding bile acids in the intestine. To compensate for the loss of bile acids, the liver uses circulating LDL cholesterol to produce new ones, which lowers its concentration in the blood — a mechanism officially recognized by EFSA as the basis for a cholesterol-lowering health claim.
Binding to the dectin-1 receptor
Mushroom-derived beta-glucans activate macrophages and other innate immune cells through this receptor.
Enhanced phagocytosis and cytokine production
Dectin-1 activation leads to a controlled immune response.
Increased gut content viscosity
Cereal beta-glucans slow glucose absorption and bind bile acids in the intestine.
Compensatory LDL use by the liver
The loss of bile acids forces the liver to produce new ones from circulating LDL cholesterol, lowering its concentration.
Evidence: moderate — based on 1 study in this database.
Benefits
Common myths
MythEvery medicinal mushroom works thanks to a unique, mysterious substance.
FactA large share of the immunomodulatory properties attributed to medicinal mushrooms stems from the same class of compounds — beta-glucans — present in varying concentrations across many species.
MythBeta-glucans from oats and from mushrooms work the same way.
FactThey have different chemical bond structures and different mechanisms of action — cereal beta-glucans act mainly mechanically in the gut, while mushroom-derived ones act immunologically via the dectin-1 receptor.
Forms & variants
Beta-glucans comes in several forms that differ in bioavailability and use case — the form you pick genuinely matters for how effective the supplementation is.
Oat/barley beta-glucan (1,3/1,4)
Acts mainly mechanically in the digestive tract, lowering cholesterol.
Best for: Cardiometabolic prevention
Mushroom beta-glucan (1,3/1,6)
Activates innate immune cells via the dectin-1 receptor.
Best for: Immune support, a context traditionally attributed to medicinal mushrooms
Practice
Frequently asked questions
Regular consumption of oats or barley in an adequate amount provides a documented dose of beta-glucans without the need for additional supplementation.
No — the evidence for the cardiometabolic effects of cereal beta-glucans is much more solid and officially recognized, while the immunomodulatory effects of mushroom-derived beta-glucans rest mainly on laboratory and animal studies.
Beta-glucan content and proportions vary significantly between species — you'll find details in the individual entries on specific mushrooms.
Dosage & timing
Typical dose
Cereal beta-glucans: at least 3 g daily for a documented effect on cholesterol; mushroom-derived — depends on the specific extract and species
Form
Naturally in oats, barley, and medicinal mushrooms, or as an isolated, standardized extract
The effect on cholesterol requires regular, long-term intake — this is not a one-off intervention.
Best times to take it
- Not applicable — the effect depends on regularity of intake, not a specific time of day
Safety
Side effects & contraindications
Possible side effects
Possible bloating and gastrointestinal discomfort with a sudden increase in beta-glucan fiber intake
Contraindications
Autoimmune disorders — immune system activation could theoretically worsen symptoms; worth discussing with a doctor
Interactions
Immunosuppressant drugs — theoretical interaction due to the immunomodulatory effect of mushroom-derived beta-glucans
Is it worth taking?
Who it's for
- People wanting to understand the common mechanism behind many of the medicinal mushroom entries in this knowledge base
- People with elevated LDL cholesterol considering increasing their oat or barley intake
Not for
- Autoimmune disorders — immune system activation could theoretically worsen symptoms; worth discussing with a doctor
Evidence
Worth knowing
EFSA recognized a health claim for cholesterol lowering by beta-glucans from oats and barley at an intake of at least 3 g daily.
The dectin-1 receptor, through which mushroom-derived beta-glucans act, was only thoroughly characterized scientifically in the early 21st century.
Studies
Regular consumption of at least 3 g of beta-glucans daily from oats or barley significantly lowers LDL cholesterol — an effect recognized by the European Food Safety Authority as the basis for a health claim.
European Food Safety Authority (EFSA), scientific opinion on beta-glucans, 2011
The effects of beta-glucan on human immune and cancer cells
Early-stage evidenceChan GC, Chan WK, Sze DM · Journal of Hematology & Oncology · 2009
A review of the mechanisms by which beta-glucans activate immune cells, including macrophages and NK cells, via the dectin-1 receptor.
View studySources & bibliography
Citations are illustrative for this demo version and require full bibliographic verification by the editorial team before production publication.
Compare with similar entries
About the authors of this entry
Author
dr Anna KowalczykEditor-in-Chief, Molecular Biology
Anna oversees the editorial process and scientific review of every publication in the knowledge base. She previously researched autophagy and mitochondrial biology.
50 publications on this site
Medical review
dr Piotr ZielińskiEndocrinologist
Piotr reviews content on hormones, metabolic health and supplement pharmacology.
131 publications on this site
Related entries
4.3Shiitake
A culinary-functional mushroom rich in lentinan and beta-glucans, studied clinically for immune modulation and lipid profile — one of the best-researched functional mushrooms on the market.
4.1Maitake (Hen of the Woods)
A functional mushroom also known as 'Hen of the Woods,' studied mainly for immune modulation (D-fraction) in oncology and, more preliminarily, for carbohydrate metabolism — evidence in healthy people remains limited.
4.4Lion's Mane
A functional mushroom studied for its effect on nerve growth factor (NGF) and cognitive function — human evidence is still preliminary.
4.5Turkey Tail
The mushroom behind PSK and PSP — the only fungal polysaccharides registered in Japan as drugs supporting chemotherapy. Among the most solid clinical evidence of any functional mushroom, but this is NOT a standalone cancer therapy.
4.4Shimeji (Hypsizygus tessellatus)
A popular culinary mushroom of Asian cuisine (bunashimeji/bunapishimeji), rich in beta-glucans and indole compounds — in vitro and animal studies suggest antioxidant and immunomodulatory effects.
4.3Oyster Mushroom (Pleurotus ostreatus)
One of the most popular edible mushrooms in Poland, containing a natural compound structurally similar to lovastatin — studied mainly for its effects on lipid profile and immunity.
4.2Reishi (Ganoderma lucidum)
A functional mushroom with more than 2,000 years of history in Chinese and Japanese medicine, studied for its immune-modulating effects — human clinical evidence, however, remains modest and partly contradictory.
4.2Elm Oyster Mushroom (Hypsizygus ulmarius)
A culinary mushroom closely related to shimeji, studied in the lab and in animals for antioxidant, hepatoprotective, and blood-sugar-supporting effects — with no clinical studies in humans.
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Comments (2)
- KW
Kasia W. 2 weeks ago
Very clearly explained, especially the interactions section — I hadn't seen it laid out this well anywhere else.
- MT
Marek T. a month ago
Are you planning to update this with the newest study from this year? I saw an interesting meta-analysis.