What are beta-glucans?

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)

Immunity

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

Related reading

• Reishi mushroom health benefits
• The Erbology guide to medicinal mushrooms