Mushroom Polysaccharides Explained

 

While diet can contribute to illness, some foods can also nourish and support your body. Near the top of that list are a group of powerhouse fungi called functional mushrooms. These mushroom species possess many bioactive compounds that may provide surprising benefits for human health.

One of the strongest and most well-known components of these mushrooms is their polysaccharide content. In fact, mushroom polysaccharides are one of the powerful bioactive substances that have prompted health and wellness experts to focus on mushrooms as a nutraceutical—a food that has medicinal benefits. A look at some key facts may help you to decide whether functional mushrooms hold potential benefits for you and your animals.

What Are Polysaccharides?

Before you can undertake serious consideration of what polysaccharides do, it is essential to understand what they are. Saccharides are carbohydrates, chains of sugars made up of carbon, hydrogen, and oxygen atoms. The prefix placed in front of ‘saccharides’ indicates how many sugar molecules are linked together: mono=one, di=two, and poly means many.

Monosaccharides are simple sugars, and they are sweet. Glucose (the most common natural monosaccharide) and fructose (the fruit sugar) are examples. When two monosaccharides join to form a glycosidic bond, a disaccharide is created and a molecule of water is released. Lactose (milk sugar) and sucrose (table sugar) are common disaccharides.

Polysaccharides, also known as glycans, are chains of many sugars. Some have a storage function; others are structural. Four common polysaccharides include:

• Starch: the primary energy-storage molecule in plants
• Glycogen: the primary energy-storage molecule in animals
• Cellulose: a component of the cell walls of plants, algae, and some bacteria
• Chitin: A fibrous polysaccharide forming the major constituent in the exoskeleton of arthropods and the cell walls of fungi30,

 

Digestible polysaccharides provide an energy source when they are consumed. Indigestible polysaccharides provide prebiotic dietary fiber that helps food pass through the digestive system and supports healthy gut flora.   

Potential Health Benefits of Mushroom Polysaccharides

Mushrooms contain a variety of polysaccharides, including alpha- and beta-glucans. It is the beta-glucans that get much of the attention when considering the benefits of mushrooms. The bioactivities of mushroom beta glucans include:

Digestive/Gut Flora Support^‡

Digestive enzymes are unable to break down many of the bonds holding polysaccharides together, which means that indigestible mushroom carbohydrates may act as prebiotics in the digestive tract. This fiber keeps food moving through the digestive system, but it also feeds the desirable probiotic microorganisms that contribute to a healthy gut microbiome.  The prebiotic activity of beta glucans includes:

• Support for the growth of beneficial bacteria
• A decrease in harmful bacteria
• Promotion of microbiotic diversity
• An increase in the number of bacteria that produce short-chain fatty acids

The presence of beneficial bacteria in the intestines also contributes to a healthy immune system, healthy body weight, and metabolic health.^‡

Immune Function Support^‡

Mushroom beta-glucans serve as biological response modifiers that support and activate the body’s own immune response to fight off immune challenges by modulating and potentiating both the innate and adaptive immune systems of mammals. With hundreds of studies completed and more research underway, beta-glucan polysaccharides have been proposed as a “nutritional fuel” for the immune system.^‡

The immunomodulating activity of mushroom beta glucans involves fragments of beta glucan molecules attaching to the surface receptor sites on various types of cells that comprise our immune system.  This attachment serves to modulate the activities of white blood cells, NK cells, T-helper cells, dendritic cells and other components of the immune system. While all mushrooms contain beta glucan compounds, each species contains unique beta glucan molecules with different molecular weights, side-chain attachments, and solubility.  It has been reported that the diversity of beta glucan compounds in products containing several species of mushrooms may enable more interactions with immune cell receptor sites thus eliciting a more broad-based immune response than would a single-species mushroom product.

Antioxidant Protection against oxidative cellular damage by free radicals^‡

Free radicals are unstable molecules that are generated by our metabolism and by exposure to toxins and stress.  Unless neutralized, free radicals can cause damage to cells and accelerate aging processes.  Antioxidants are molecules that are able to neutralize the damaging effects of oxidizing, free radical compounds by donating an electron to the unstable free radical molecules.  Beta glucans in addition to being immunomodulators and supporting gut health, also function as antioxidants.

Important Considerations for Choosing Functional Mushroom Products

Though mushroom polysaccharides get a lot of attention, there are many bioactive compounds in mushrooms that have the potential to provide health benefits. In some cases, the fruit body and the mycelium contain different compounds or different amounts of specific substances. For these reasons, a functional mushroom product that contains both mycelium and fruiting body provides a more complete profile of beneficial, bioactive substances.

Another consideration involves the difference between whole mushroom powder and extracts. Though a hot-water extract may have been prepared to contain a standardized dose of hot-water soluble beta-glucans, the extraction process eliminates or may denature other beneficial compounds. These may include:

• Phenolic and flavonoid compounds that act as antioxidants
• Compounds such as triterpenes that are not soluble in hot water ^‡

Many scientists studying the effects of functional mushrooms recommend consuming both the fruiting bodies and mycelial  biomass of medicinal mushrooms to capture all of the health-promoting compounds produced over the entire life cycle of the mushrooms that provides benefits for the immune and other body systems.^‡

^‡These statements have not been evaluated by the Food and Drug Administration. Functional mushroom products are not intended to diagnose, treat, cure or prevent any disease.