Beta-glucans are polysaccharides – long chains of glucose – found in the cell walls of fungi, yeasts, algae and bacteria, as well as in cereals such as oats and barley. But not all beta-glucans are the same, and that matters when you choose a mushroom supplement.
Mushroom beta-glucans vs cereal beta-glucans
The beta-glucans characteristic of mushrooms have a backbone of glucose linked by β-(1,3) bonds, with β-(1,6) branches. Cereal beta-glucans, by contrast, have β-(1,3) and β-(1,4) bonds. In Great Britain, authorised health claims exist only for oat and barley beta-glucans; there are none for mushroom beta-glucans.
Why cereal can end up in mushroom supplements
Cereals are a common growing substrate for mushrooms. If only the fruiting body is harvested, the substrate is left behind. But if the mycelium is harvested from a solid grain substrate, the two cannot be separated – so the final product contains both mushroom and cereal, and a 'beta-glucan' figure may include cereal starch and beta-glucans.
What independent studies have found
A 2017 study in Scientific Reports analysed 19 supplements labelled as containing Reishi and found that only 5 contained the beta-glucans characteristic of the mushroom. A 2023 study comparing labels with DNA analysis found that only 5 of 19 products matched their label.
What to look for on the label
- The species and the part used (fruiting body or mycelium) and the growing medium.
- The content of β-(1,3)(1,6)-D-glucans specifically, not just 'polysaccharides'.
- The analytical method used and batch-specific results.
Our approach
Our strains come from our own strain bank, and our extracts are standardised and tested up to three times during production. We publish the beta-glucan content of our products – for example, Mico-Mix shows its content of lentinan (from Shiitake) and grifolan (from Maitake). Find out more on our quality page.