Beta-Glucan: The Microbiome Fixer

A reader that does microbiome analysis of her ME/CFS daughter’s microbiome using Microbiome Prescription expert system sent me this note with some literature. The daughter has Celiac Disease and ME/CFS.

Your wonderful system recommended beta-glucans [also written β-Glucan] for my daughter,  and when I looked further, I found this. I’m trying her on them for a month-, after testing her for reactions for three days- the first week has been hopeful. Will keep you posted if you wish.


β-Glucan is a nonstarch polysaccharide having documented health benefits and industrial applications. It can be extracted from various sources, including cereals, bacteria, molds, and fungi. The chemical nature of extracted β-glucan from these sources differs slightly. This variation in chemistry defines its industrial uses and health benefits.

Biopolymers for Food Design, 2018


There is not much literature available for ME/CFS.

  • “The findings showed that the beta-glucan supplementation significantly improved cognitive fatigue (assessed with FIS-40 scores) after the 36-week treatment compared to the baseline (p = 0.0338). Taken together, this study presents the novel finding that yeast-derived beta-glucan may alleviate cognitive fatigue symptoms in ME/CFS.” [2023]
  • β-Glucan Improves Conditions of Chronic Fatigue in Mice by Stimulation of Immunity [2020] Reduces TNF-α (which is connected to mast cell issues)
  • Effects of β-(1,3–1,6)-d-glucan on irritable bowel syndrome-related colonic hypersensitivity [2012]
    “β-Glucan did not affect the pain response in general but specifically affects the visceral pain response.”
  • Serum concentrations of 2′,5′-oligoadenylate synthetase, neopterin, and beta-glucan in patients with chronic fatigue syndrome and in patients with major depression. [1994]
  •  the dosage of supplementation ranged from 2.5 to 1000 mg daily [of beta-glucan] for up to 6.5 months … The primary physiological outcome of the majority of the interventions was immunomodulation, which resulted in (a) strengthened immune defense that reduces the incidence and symptoms of cold, flu and other respiratory infections and (b) improvement of allergic symptoms.” [2021]
  • β-glucan attenuates cognitive impairment via the gut-brain axis in diet-induced obese mice [2020]

Some literature for Autism

Many Sources of Beta Glucan

Often the expert system on Microbiome Prescription comes up with Barley as a strong recommendation for ME/CFS people. Barley is an excellent source. Personally, I have oats or barley porridge a couple of times every week. The impact of the β-Glucan in the Barley may be the mechanism — we just do not have as many studies as we do for Barley.

  • “The primary sources of food β-glucan for humans are cereals (especially oats and barley), fungi, algae, and yeast ” [2023] A table from this article is below
  • β-glucans bind to specific receptors on immune cells and initiate immune responses…. In vitro study found that the fermentation of barley and oat β-glucan by human fecal samples show variations in SCFAs production and the bacterial populations of Clostridium histolyticum and the ratio of Bacteroides–Prevotella species. Absorption of these SCFAs by the gut epithelial cells helps in regulating cell differentiation, proliferation, apoptosis, and gene expression (210). Butyrate increases the protein expression of tight junctions such as ZO-1 and claudin-1, resulting in enhanced intestinal barrier function.”
    β-glucan is an essential food ingredient in controlling metabolic dysregulations linked to metabolic syndrome. β-glucans have a very minimal probability of having any unfavorable side effects and are reasonably inexpensive.” [2023]

Bottom Line

Real simple: Barley or Oats porridge for breakfast each day! Since there are some chemical differences between the β-glucans in these two grains– rotate between these (and different brands) at least monthly.

Using the generic suggestions for me/cfs we see both barley and B-glucan are positive (but oats are slightly negative). The more detailed citizen science suggestions are still be worked on, but I expect similar.

Reviewing Clinical Trials, my impression is 1 gram/day of β-glucans which translates to 20 grams of Barley or 40 grams of Oats per day.

“30g uncooked oats or barley will make a fairly small bowl of porridge whilst 70-80g will provide a particularly large serving for one person. Traditional porridge recipes tend to use oatmeal with approximately 200ml of water per 50g oats, and a pinch of salt.”

University of Aberdeen

Some people will advocate just eat mushroom. While correct that it contains beta-glucans, we need to be careful not to slip into homeopathic dosages!

Among those, mushrooms feature a particularly high level, so it’s no exaggeration when we say “for beta glucans, look to mushrooms!” The amounts of beta glucans found per 100 g of raw mushroom include 2.3 g (maitake), 2.0 g (bunapi), 1.9 g (eryngii), 1.8 g (bunashimeji) and 1.5 g (shimofuri hiratake) (Hokuto data).

When we go to typical US mushrooms (i.e. Button), we drop to .75 g/100 grams [FDA]. So we are talking about 5-6 oz of mushrooms per day. That 3/4 of the typical mushroom package per day per person.

Celiac and Gluten Sensitive Issue

Most beta glucan supplements are produced from Saccharomyces cerevisiae (thus gluten free). For example the item below is about US$17.00 and gives 100 days at 1 gram per day.

I should note that there are different forms of beta glucan, for example above it is the 1,3/1,6 forms. Another product has 1,3/1,4 and is derived from Oats (you will have to write the company to see if it is gluten free or low gluten).

The cost per gram is much lower as bulk powders than with pre-filled “premium” capsules – the same volume of beta glucan can be as high as $250 (12x more) with some products.