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Glucan and immunomodulation: Helping the body heal itself

Several studies in the past few decades have been focused on immunomodulators, a group of naturally-occurring substances that have been found to regulate and modulate the body’s immune system. Its effects cover a wide range of potential benefits covering a variety of disease and sicknesses. Of these immunomodulators, beta-glucan presents some of the most promising results.

Beta-glucan is a known plant constituent, and the science community recognizes beta-glucan as a powerful immune stimulant and antagonist to both benign and malignant tumors. It is also known to lower cholesterol and triglyceride level, normalize blood sugar level, heal and rejuvenate the skin, and fight against infections.

Sources and differences in glucans

Glucans are derived from different sources and have different structures and molecular weight. These differences have a large impact on the activity of beta-glucan. Large molecular weight beta-glucans (such as zymosan) can activate leukocytes, stimulate phagocytic, cytotoxic, and antimicrobial properties. Low molecular weight beta-glucans have a biological activity but the cellular effects are vague, while very short beta-glucans are considered to be inactive.

Depending on location, researches about beta-glucan in Euro-America were based on the immunomodulatory effects of zymosan – a mix of polysaccharides isolated from the cell walls of yeast (Saccharomyces cerevisiae). It stimulates macrophages and prompts the release of cytokines. Upon detailed examination of zymosan, beta-glucan was identified as the part which had the primary effect. In Asia, Japan’s tradition of using medicinal mushrooms led to the discovery of beta-glucan. The detailed studies on the biological effects of mushroom concluded that the main cause of immunomodulation is due to beta-glucan.

Glucan as an immunostimulant

Beta-glucan is recognized as an immunostimulant. The binding of beta-glucan to specific receptors activates macrophages and phagocytes, and leads to the secretion of cytokines and other substances that initiate inflammatory responses.

In addition, beta-glucan is widely used against both bacterial and protozoan infections. It enhances the efficacy of antibiotics against antibiotic-resistant bacteria. The protective effect of beta-glucan was observed in experimental infections with Staphylococcus aureus, Escherichia coli, Streptococcus suis, Mesocestoides corti, Trypanosoma cruzi, Eimeria vermiformis, Bacillus anthracis, Leishmania major and L. donovani, C. albicans, Toxoplasma gondii and Plasmodium berghei.

About 40 years ago, the anti-tumor activity of beta-glucan has been noticeably demonstrated. The recent studies regarding beta-glucan demonstrated that it actively works with antibodies. These antibodies naturally occur in different cases of cancer. Further experiments also showed that daily therapy with beta-glucan resulted in a 70%-95% reduction in tumor weight compared with the control group.

Soluble beta-glucan is CM-glucan

Beta-glucans from baker’s yeast (Saccharomyces cerevisiae) possess low solubility which makes it difficult to be absorbed. With the process of carboxymethylation, beta-glucan transforms to CM-glucan (carboxymethyl-glucan or sodium carboxymethyl beta-glucan). CM-glucan is a highly soluble glucan that can be readily absorbed by the body. It has enhanced ability to bind with glucan receptors which stimulates the generation of macrophages and neutrophils, and enhances phagocytosis.

The stimulation of macrophage prevents the appearance of Th₂ response which restricts asthma episodes, reduces the duration and severity of asthma attacks, and prevents occurrences of allergic rhinitis. CM-glucan may also lessen the frequency of recurrent colds and flu and respiratory tract infections. At the same time, it provides a suitable environment for patients undergoing treatment for tuberculosis. In general, CM-glucan provides a shorter duration of treatment and faster recovery from infections and diseases.

As discussed earlier, CM-glucan has been proven to have anti-tumor activity. It modulates innate and adaptive immunity, stimulates hematopoiesis after multiple doses of radiation, increases the total leukocyte counts which may result in cancer prevention and good outcome of therapy, reduce side effects of cancer treatment, and improve the quality of life as the disease progresses.

CM-glucan also showed beneficial effects on the skin. It protects skin cells against the decrease of antioxidant molecules due to UV-A exposure and promotes the growth of keratinocytes. Keratinocytes forms a barrier against bacteria, fungi, parasites, viruses, heat, UV radiation, and water loss. In various studies, the pretreatment of skin with CM-glucan offered considerable protection against skin damage caused by a detergent or UV-A irradiation. In addition, CM-glucan also enhanced the renewal rate of the stratum corneum.

In conjunction with these effects, the carboxymethylation and increase in solubility of glucan do not show any toxicity and adverse effects, but it enhances the biological properties such as antioxidant and immunomodulation compared with insoluble beta-glucan.

Through various researches and experiments, the use of glucan to stimulate the immune system and to fight against infections has been established for a long time. With the carboxymethylation of beta-glucan, the increase in solubility brings more beneficial and enhanced properties compared with what the beta-glucan already offers.

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