What are beta-glucans?

9 min readMar 2, 2021


Beta-glucans, β-glucans, Beta-d-glucans, polysaccharides… typing these into a search engine can lead you down a rabbit hole of scientific jargon. Luckily, behind all the technical terms, beta-glucans are not too complicated, and may have benefits for your health. Let’s take a refreshingly simple look at what they are, and why they might make a great addition to your diet.

What are beta-glucans?

To a simple question, a simple answer: beta-glucans are a type of fibre.

More specifically, they are a type of polysaccharide. This simply means that their structure is made up of several simple sugar molecules (monosaccharides) stuck together.

Other names for polysaccharides, which you might come across while reading up, are ‘sugar polymers’ and ‘glycans’. These terms all mean the same thing: a molecule made up of several monosaccharides.

Not all polysaccharides are created equal, however. There are lots of different types, including cellulose (used in plant cell walls), glycogen (which our livers use to store energy) and starch.

They all serve different purposes and are found in different organisms. Beta-glucans are just one specific type of polysaccharide.

You may also come across the term beta-d-glucans. This just refers to a particular type of beta-glucan, which is found specifically in fungi and yeast. → See Medicinal Mushroom Products

Where can I find them?

You can find beta-glucans in the cell walls of microorganisms such as bacteria and yeast, as well as algae, lichens, seaweed and many plants.

Fortunately, lots of these plants are edible, providing a source of beta-glucans for our diets. For example, you can get them through eating cereals such as oats and barley as well as seaweed and algae.(1)

Medicinal mushrooms such as reishi, cordyceps, turkey tail and chaga all contain high amounts of beta-glucans.

It’s important to note that the molecular structure of beta-glucans found in cereals and those found in fungi are slightly different. In cereals, they tend to have a linear structure, whereas fungal types have a branched structure.(2) Their structure gives them slightly different properties.

They can be quite tricky to detect in foods. There is only one universally-recognised test, called the beta-glucan assay test. This is what we use to check the content of our medicinal mushroom products.

Scientists are only beginning to study beta-glucans and their possible benefits for our health. That said, there are a few paths of study which are proving particularly interesting.

Gut health

Beta-glucans are a prebiotic.(2) This means that while you can’t digest them yourself, they provide a nourishing meal for the ‘good’ bacteria living in your gut.

As a quick reminder, good gut health is all about maintaining a balance between the different types of bacteria that live there. ‘Good’ bacteria keep ‘bad’ bacteria (which might cause disease if allowed to proliferate too freely) in check.

While humans lack the ability to break prebiotic fibre down, your ‘good’ gut bacteria can ferment it and extract the precious nutrients within.

Researchers found that beta-glucans from oats supported the growth of Lactobacilli and Bifidobacteria, considered to be ‘good’ gut bacteria in humans.(3)

When functioning healthily, your ‘good’ gut bacteria play an important role in your immune system and overall wellbeing. So, it’s important to keep them well-fed!

Prebiotics, by definition, either increase the numbers of ‘good’ bacteria in your gut or stimulate their activity. This, in turn, has benefits for your overall health.

Heart health and cholesterol

Interestingly, the improvements beta-glucans provide for your gut health also have knock-on effects elsewhere in the body.

A recent study found that eating beta-glucans in oats stimulated an increase in the population of a type of gut bacteria called Verrucomicrobia.

The regulation of this type of bacteria by beta-glucans also caused an improvement in plaque build-up within the walls of the aorta. Similarly, it helped to control the negative health effects of fatty deposits in arteries.(3)

Given that cardiovascular disease is the leading cause of death worldwide,(4) adding some beta-glucans to your diet may be a good choice for your long-term health.

A study on male participants with high cholesterol levels found that soluble beta-glucans (such as those found in oats) led to reduced blood cholesterol levels over the long term.(3)

The anti-cholesterol action of insoluble beta-glucans, which are found in mushrooms, is less well understood, but studies continue to unravel their secrets.

Research has shown that consuming fungi reduces cholesterol levels in animals. Increasing their intake of these fungi, on the other hand, might lower the animals’ risk of cardiovascular disease.(3)


The scientific community is well aware of beta-glucans. Researchers seem to prize them highly for their immunity-boosting properties. (For a quick refresher on how your immune system works, and the cells involved in protecting you from pathogens, head to our winter immunity article.)

Beta-glucans from mushrooms seem to support the immune system by enhancing the function of both microphages and natural killer cells.(5)

Microphages are immune cells (more specifically, they are a small phagocyte cell). Phagocytes help eliminate pathogens from your body by engulfing them; the pathogen is effectively swallowed up by the phagocyte and broken down so it can no longer do you any harm.

A natural killer cell is a type of lymphocyte which detects and kills cells which have been infected by viruses. They can help control the early signs of cancer.(6)

Beta-glucans also activate the complement system.(5) This lesser-known part of your immune system is made up of lots different plasma proteins which coat a pathogen, tagging it for destruction by other immune cells. Its action ‘complements’ that of antibodies, hence its name.(7) → See Medicinal Mushroom Products

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“Beta-glucans from mushrooms seem to support the immune system by enhancing the function of both microphages and natural killer cells.”

Protection from disease

We know that beta-glucans can help stimulate the cells of your immune system, which is exciting news for scientific researchers around the world. As a result, many different studies are underway to try to understand how they can help protect us from disease.

A study on piglets showed that beta-glucans had a protective effect against e-coli infection.(8)

Another fascinating study looked at their effect on respiratory infections in firefighters. People in this line of work are more susceptible to this kind of disease because they are likely to inhale smoke as part of their job.

Some of the group were given beta-glucans, and others were given a placebo. The researchers then looked at how often they developed an upper respiratory tract infection (URTI). Participants were considered to have developed an URTI if they showed symptoms for two days or more.

At the end of the study, the firefighters who had taken beta-glucans reported fewer symptoms of URTI and also had better overall perceived health.(9)

The results are in line with another study which showed a similar effect in marathon runners. As an added boost, the runners’ improved post-race immunity was associated with better mood, increased vigour and reduced fatigue.(10) → See Medicinal Mushroom Products

How can you get more beta-glucans in your diet?

To add beta-glucans to your diet, simply make sure you’re eating plenty of oats, barley, and other foods which naturally contain them.

You might also want to consider adding medicinal mushrooms to your diet, like the reishi shown above.

Reishi, lion’s mane, cordyceps and turkey tail mushrooms all contain beta-glucans. Indeed, these special polysaccharides are thought to be responsible for many of their health benefits.

Each different type of mushroom contains beta-glucans with different structures, which may explain their varied health benefits. This reveals another positive to introducing mushrooms into your diet; they provide your dose of beta-glucans while also allowing you to focus on a particular area of your health.

Lion’s mane mushroom, for example, is high in beta-glucans but may also support mental and cognitive health.

Meanwhile, reishi mushroom is associated with boosting your energy levels, and turkey tail is thought to be good for your gut health and immunity.

It’s easy to incorporate them into your routine by combining a small amount of our organic mushroom powders into hot drinks like tea, coffee and hot chocolate.

While it might seem strange to add mushrooms to your americano, the flavour of coffee pairs well with them and help to eliminate any bitterness coming from the mushroom. → See Medicinal Mushroom Products

What to look out for when buying medicinal mushrooms

If you’re interested in increasing your intake of beta-glucans via medicinal mushrooms, there are a few things you should look into before buying.

Lots of suppliers promote the fact that their mushrooms are high in polysaccharides, but this might not necessarily equate to their beta-glucan content.

Most medicinal mushrooms (and indeed the ones you buy from the supermarket) are grown in a controlled environment, such as indoor farms. This is because over-foraging for mushrooms in the wild can disrupt the ecosystem of natural areas, and also because it’s important to control what the mushrooms grow on. In the wild, they can grow on lots of different things, which produces mushrooms with different qualities and nutritional content.

Some medicinal mushrooms are grown on starch, such as rice. It’s a good way of providing the mushrooms with the nutrients they need to grow. Unfortunately, though, it’s very difficult to separate the starch from the mushroom when it’s time for the harvest.

That means that when the mushrooms are processed (e.g. ground into a powder or made into a supplement), all that starch is included as well.

Starch is a kind of polysaccharide, but it doesn’t really have any benefits for your health. So while you might see an impressive percentage of polysaccharides on the label, it’s very important to check what proportion is made up of healthy beta-glucans. → See Medicinal Mushroom Products

Look for a wood or a liquid medium

When buying medicinal mushrooms, look for a supplier that uses a liquid or a wood medium. The latter is sometimes called a ‘lignocellulosic substrate’ — this simply means ‘cellulose’, or plant matter, derived from ‘ligno’, or wood.

When either of these substrates are used, it’s easy to separate the mushroom during harvesting, so you can be confident that your mushroom product contains only mushroom!

There’s also an added benefit to using a liquid food for mushrooms. As the environment is carefully controlled, the growers can provide more of the specific natural nutrients which encourage a higher beta-glucan content in the final mushroom product.

It’s similar to the way that high quality soil produces better crops. More nutrients in the liquid food produce a better quality mushroom.

While the mushrooms are grown in controlled conditions, it’s still important to make sure that they are being fed on natural foods, and that no pesticides or chemicals are being used during their growth. Make sure you buy from a supplier that is certified organic.

More on mushrooms

If you’re interested in finding out more about adding medicinal mushrooms to your routine, there’s lots of information available in our Erbology Editorial section.

There, you can find out all about the health benefits of reishi, lion’s mane, cordyceps and turkey tail, as well as a bit about their traditional use and current research into their effects.

Or, if you’re primarily interested in beta-glucans for their immunity-boosting potential, take a look at our Immunity Mushroom Blend. It’s a mixture of powerful mushrooms known for their positive effects on your immune system and is naturally high in beta-glucans.

Needless to say, all of our mushroom powders are 100% organic, high in beta-glucans, and grown on liquid or lignocellulosic substrates, so there’s no unwanted filler.

So, why not whip up a deliciously indulgent hot chocolate with a half-teaspoon of medicinal mushroom? It’s perfect for a cosy treat with health-boosting benefits.

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