The Powerful Benefits of Beta-Glucans in Functional Mushrooms

Functional mushrooms, including shiitake, maitake, turkey tail, and reishi, have a history of versatile health benefits spanning centuries. One reason these medicinal mushrooms can do everything from helping the immune system and digestive tract to improving heart health is thanks to one of their unique components called beta-glucans (also written β-glucans). 

Beta-glucan is a soluble fiber located primarily in the cell walls of mushrooms and whole grains, known to lower blood sugar, defend against infections, and even kill cancer cells. 

This article provides an in-depth look at the health power of beta-glucans in functional mushrooms, including how beta-glucans work, their many benefits, and their most bioavailable forms for diet incorporation. 

What Are Beta-Glucans?

​​Beta-glucans are a type of dietary fiber called polysaccharides that occur naturally in the cell walls of functional mushrooms and foods like oats, wheat, and barley. Polysaccharides are carbohydrate arrangements made of long simple sugar molecule chains. They support cells and tissues, provide energy storage, and offer powerful health benefits. 

The body doesn’t produce beta-glucans, so people must obtain them through food like mushrooms and supplements. 

How Do Beta-Glucans Work?

β-glucan is a soluble fiber that dissolves in water and forms a thick, gel-like, indigestible substance. This polysaccharide travels through the gastrointestinal (GI) tract without the body breaking it down or absorbing it, allowing people to feel fuller, longer. As beta-glucans travel through the GI tract, they can carry excess lipids like cholesterol out with them. This process positively impacts metabolism, blood sugar, and cholesterol levels. 

Beta-glucans also act as disease-fighting agents by triggering events that help regulate the immune system and make it function more efficiently. Specifically, beta glucans stimulate the activity of immune cells that ingest and demolish invading pathogens and energize other immune cells to attack.

Benefits of Beta-Glucans

Studies show beta glucan positively affects digestion, which can help reduce heart disease and cholesterol levels. Beta-glucans, particularly those in functional mushrooms, also stimulate the immune system, helping to fight bacteria, viruses, and tumors and prevent infections. 

Beta-glucans play a vital role in the following body functions:

• Stabilizing blood sugar levels
• Regulating cholesterol 
• Lowering high blood pressure
• Benefiting digestive and gut health
• Boosting the immune system
• Stopping infections from viruses and bacteria
• Fighting tumors and cancer cells

The Immune Benefits of Beta-Glucans

Human white blood cells have receptor sites on their surfaces that bind with polysaccharides like beta-glucan, like a lock on a door that needs the right key to open. When this happens, beta-glucans stimulate the white blood cells to latch onto tumors and viruses and release chemicals to destroy them.

Research shows beta-glucans help the immune system function optimally by:

• Increasing secretory immunoglobulin A (IgA) levels, a protective substance that lines nasal passages, throat, and airways. 

• Activating macrophages, monocytes, and neutrophils, specialized white blood cells that actively engulf and destroy bacteria and tumor cells. Macrophages also analyze immune system threats and send chemical messages to other white blood cells to respond. 

• Enhancing natural killer (NK) cells, which destroy cells that have become cancerous or infected with viruses. 

Beta-Glucans and Heart Health

Research indicates that beta-glucan promotes heart health and positively impacts the body in several ways that reduce heart risk:

• Slows the absorption of sugar into the bloodstream, helping to support healthy blood sugar levels.
• Attaches to cholesterol in food, helping to excrete it from the body and lower cholesterol levels. According to one study, consuming three grams of beta-glucan per day for eight weeks decreased LDL cholesterol levels (the bad kind) by 15% and reduced total cholesterol by nearly 9%.
• Positively impacts metabolism by producing short-chain fatty acids in the intestine, which increases gut hormone secretion. Changes to the gut’s microorganisms lead to reduced foot intake and improved insulin sensitivity. 
• Exhibits antioxidant properties that can help neutralize harmful free radicals prevent inflammation, and protect against chronic conditions like heart disease.

Cancer

Beta-glucans show significant potential in their cancer-fighting abilities. Studies show this soluble fiber can be a natural cancer treatment by stimulating the immune system to attack malignant cells, inhibiting tumor growth.

Most US-based research on beta-glucans’ cancer potential involves animal studies. However, other countries have performed human trials, reporting a positive impact on patient survival and quality of life.

• Multiple Asian studies show that lentinan, a type of beta-glucan found in shiitake mushrooms, can reduce tumor activity and lessen the side effects of cancer treatment. Other research shows interest in lentinan in mushrooms for treating gastric cancer.
• Japan has been using a mycelium-extracted polysaccharide for clinical tumor treatment since 1977. In 1989 the country reevaluated the compound and expanded its use in combination with chemotherapy for patients with gastric cancer, colorectal cancer, and small-cell lung carcinoma. 
• A 2019 review says diets containing beta-glucans may prevent or slow cancer development, including breast and gastric cancer.

Helping the Body Conquer Infections

Beta-glucans work as Biological Response Modifiers (BRMs), stimulating an increased immune response and enabling a more effective reaction for fighting off infections. Beta-glucans can also help the body battle antibiotic-resistant bacteria and viruses that cause upper respiratory infections.

• Multiple animal studies show beta-glucan could help activate immune cells and protect against infection.
• A 2008 study on firefighters showed beta-glucans could mitigate the symptoms of the common cold, with participants who consumed beta-glucans having 23% fewer upper respiratory tract infections.

Gut Health

An imbalance in gut bacteria can lead to an overgrowth of potentially harmful microorganisms and disrupt overall health. As a soluble fiber, β-glucan ferments in the lower digestive tract and balances the gut microbiome. 

• Acts as prebiotics. Beta-glucans act as food for good bacteria, stimulating the preexisting good bacteria to multiply in the gut. This process helps relieve gas, bloating, and abdominal pain symptoms. 
• Create short-chain fatty acids, which support healthy cholesterol levels and decrease inflammation.

Food Sources of Beta-Glucans

Mushrooms

Mushrooms are an excellent source of beta glucans. But concentration of beta-glucans varies based on the species, growth environment, and mushroom maturity. Additionally, beta glucan molecules differ in structure from species to species, a significant factor in determining their bioactivity. 

The wild-grown edible mushrooms below have some of the highest beta glucan content, according to this quantitative evaluation. 

• Plums and custard mushrooms
• Jelly ear mushrooms 
• Velvet bolete
• Boletus pinophilus
• Pine bolete
• Granulated Bolete

A different study looked at commercially cultivated mushrooms, which are more common on grocery store shelves. Specifically, researchers looked at different Agaricus bisporus (white button mushrooms), Lentinula edodes (Shiitake), Cantharella cibarius (chanterelle mushrooms), and Pleurotus ostreatus (oyster mushrooms). 

Chanterelle had the highest overall beta glucan content combining its cap and stalk, followed by shiitake mushrooms. Oyster mushrooms came in third followed, and white button mushrooms came in last. 

Maitake mushrooms don’t appear in these studies. Still, they’re known to contain beta-glucans with several branching side chains, increasing the likelihood the polysaccharides will reach and activate a greater number of immune cells. Lion’s Mane, Turkey Tail, and Reishi mushrooms also have notable beta glucan content. 

• Lion’s Mane (Hericium erinaceus) is rich in beta 1–3, 1–6 glucans known to have immunomodulating and antitumor effects.

• Reishi mushrooms' (Ganoderma lucidum) (chemical contents regularly contain about 25% total polysaccharides. 

• Turkey Tail (Trametes versicolor) has one of the highest beta-glucan content in commercially grown functional mushroom species–60.79%, according to one chemical screening.  

Conversely, portobello mushrooms have some of commercial edible varieties' lowest beta glucan content. 

Other Food Sources

In addition to medicinal mushrooms, beta-glucan occurs naturally in various food sources. Grains like barley and oats contain the highest concentration of beta-glucan. One and a half cups of cooked oatmeal or three packets of instant oatmeal provide three grams of beta-glucans, while one cup of cooked pearl barley contains approximately 2.5 grams of beta-glucans. 

Beta-glucans also appear in many other foods, although to a lesser extent, including:

• Wheat
• Durum wheat
• Rice
• Sorghum
• Rye
• Maize
• Seaweed

Beta-Glucans Bioavailability 

Beta-glucan is most abundant in raw foods because processing and cooking will reduce the beta-glucan content. Eating raw oats is virtually impossible, so consumers should look for whole grains as close to their natural states as possible. For example, steel-cut oats will have more polysaccharides than instant oatmeal. Additionally, oat flour and pearl barley are better than barley flour.

Consuming raw mushrooms also presents a bioavailability issue because mushroom cells contain chitin, a rigid and challenging-to-digest material. Cooking mushrooms is essential to break down the chitin, but this process also reduces the beta-glucan content. People can consume mushroom powders or capsules to avoid this heat-driven degradation. 

• According to the FDA, 3 grams of beta-glucans daily can lower cholesterol and prevent heart disease. 
• Clinical studies show a dose between 100 and 500 mg daily can help support optimal immune function. 

The Bottom Line

Beta-glucan is a robust dietary fiber found in the cell walls of mushrooms and other foods that don’t break down in the digestive system. They slow digestion, helping to stabilize blood sugar and cholesterol levels and interact with immune cells. Scores of research show that adding beta-glucan to a daily diet—either in the form of supplements or foods containing the compound—can significantly help the body fend off everything from the common cold to heart disease and cancer. 

Not all beta-glucan sources are created equal, so finding scientifically validated products is crucial. With the explosion of functional mushroom products, quality-tested varieties will rise above the competition. 

ACS Laboratory tests functional mushroom products for purity with the same quality levels as our award-winning cannabis and hemp testing. Contact ACS to start testing mushroom products today. 

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