The superior fungi are composed of a myriad of molecules with proven therapeutic qualities such as polysaccharides, dietary fibre, and terpenes. Within the group of polysaccharides are the β-glucans (beta-glucans); bioactive compounds which have been shown to act on the immune system, regulating our immune response. They also affect the functioning of the cardiovascular system and the development of oncological processes.
According to published scientific evidence, beta-glucans are able to effectively stimulate our defences against bacterial, viral or parasitic infections. In addition, they act as biological response modifiers to the host’s immune system, which has implications in the protection against various diseases.
Biochemically speaking, beta-glucans are long chains of glucose molecules that are considered soluble dietary fibres. Generally oats are the main grain associated with containing beta-glucans. However, beta-glucans are not exclusive to oats and can be found in multiple other foodstuffs including other cereals, algae and mushrooms. Beta-glucans of fungal origin are of particular interest because of their bioactive potential and their specific structure; complex branches that give rise to triple helical formations, which are essential to their antitumor activity.
Foods containing beta-glucans include:
- Basidiomycete fungi such as Royal Sun Agaricus, Lion’s Mane, Cordyceps, Coriolus versicolor, Reishi, Shiitake, Maitake, Coprinus, Polyporus…
- Cereals such as barley, oats, rye, corn, and rice
- Seaweed and algae
Mushroom beta-glucans: more complex
The beta-glucans from fungi (and some cereals) possess special chemical qualities. They have β-(1,3) bonds in their main glucose chain and have β-binding branches (1,6). Numerous studies have determined that it is this branched structure that is key to their action on the immune system.
The following structural aspects of beta-glucans relate to their level of activity:
- solubility: the higher the solubility the greater the activity observed.
- molecular size: the higher the molecular weight, the greater the activity observed.
- branch points: branch points type β-(1,6).
- branching form: the helical tertiary structure of fungal glycans is important to the immunostimulatory activity they exert. By contrast, beta-glucans in algae have a linear structure.
How are beta-glucans activated?
Beta-glucans are a constituent of everyday foods. However, they can also be consumed as a food supplement in which the concentration of beta-glucans can be standardised into a so-called therapeutic dose. In either case, beta-glucans are consumed by mouth, which leads to the following question: how do they interact with the immune system?
The gastrointestinal system
70-80% of immune system cells are located in the intestinal mucosa. This gut associated lymphatic tissue (GALT), in conjunction with the nostrils and the skin, is one of the main access routes for contact with pathogenic organisms. GALT in the digestive system allows orally administered beta-glucans to be absorbed and transported to the spleen, lymph nodes and bone marrow where, by interacting with immune cells, they can help activate the immune response.
Additionally, as elucidated in other articles, fungi contain good levels of prebiotics, which stimulate the growth of the intestinal microbiota, thus providing a global benefit.
Beta-glucans and the immune system
Some of the polysaccharides and proteoglycans isolated from medicinal mushrooms such as the Royal Sun Mushroom have been shown to have antitumor activity. In an immunology study, Royal Sun Agaricus, scientific name, Agaricus blazei, showed potential as both a therapeutic and a preventive agent for influencing the immune system.
Beta-glucans and allergies
In addition to studies exploring their antitumor effects, there are also studies evaluating the effect of beta-glucan polysaccharides on allergies and their associated symptoms: from rhinitis, conjunctivitis, itchy eyes and throat, postnasal drip and cough to fatigue and physical discomfort.
As explained in the LEARN section of our website, when an allergic reaction occurs, our body increases its defensive response. The body deviates from its usual equilibrium, also called homeostasis, into an excitatory response of the Th2 immune state, a proinflammatory state where a range of biochemical reactions occur, including the release of histamine, which can cause the aforementioned symptoms.
A study published in 2013 by The Journal Food Sciences and Nutrition reported the results of a randomized trial conducted over 4 weeks during which the experimental group was administered a formula containing beta-glucans. In comparison with the placebo group, subjects who consumed beta-glucans reported the following improvements:
- General allergy symptoms were reduced by 28%
- The severity of associated symptoms was reduced by 52%
In terms of general wellbeing, the experimental group also reported improvements in emotional wellbeing, physical health and energy levels. The reduction of specific symptoms associated with allergic processes was also reported. The following results stand out:
- Insomnia was reduced by 53%
- Eye related symptoms, including those relating to ocular mucous membranes were reduced by 57% (for example, watery eyes, redness, and itching)
- Problems related to the nose such as itching, excess mucus and other issues were reduced by 50% (postnasal drip, itching, sneezing, and congestion)
The sum of these improvements in the participating allergy patients was reported as an improvement in overall quality of life of 56%.
Biological Response Modifiers (BRM)
The ability of beta-glucans to stimulate immune system cells such as macrophages, neutrophils and NK cells has led to new clinical applications in which they are used as adjuvants for their anticancer potential to improve the effectiveness of hospital treatments.
There are studies that indicate that beta-glucans can prevent oncogenesis and, due to their impact on immune cells, beta-glucans can also inhibit tumour growth and expansion. Additionally, when used as adjuvant treatment alongside chemotherapy and radiotherapy, beta-glucans have been shown to encourage the regeneration of red blood cells (haematopoiesis) after damage to the bone marrow.
Dyslipidaemia, hypertension and obesity
There are multiple studies, which highlight the functional use of dietary fibre, of which beta-glucans are a useful source. Several scientific articles have documented the benefits of beta-glucans in specific issues related to cardiovascular health such as dyslipidaemia, hypertension and obesity.
As discussed, the solubility and molecular weight of beta-glucans determines their level of activity on the immune system as well as on the cardiovascular system, specifically in relation to their Hypocholesterolemic effect. Therefore, beta-glucans from fungi offer an increased benefit due to their greater solubility, molecular weight and more complex branching structure.
We hope this brief summary of beta-glucans highlights both the therapeutic possibilities of using beta-glucan rich food sources, and beta-glucan supplements in the development of new health treatments focused on improving the immune and cardiovascular systems.
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