The National Cancer Institute defines beta-glucan as a polysaccharide found within the cell walls of plants, bacteria and fungi. Beta-glucans are most commonly extracted from oat bran and edible fungi in the form of mushrooms. The most highly commercialized mushroom for use of beta-glucan comes from the large Japan mushroom, Maitake. American Cancer Society studies are ongoing to test the immune-enhancing effects of Maitake in combination with the anti-cancer monoclonal antibody drug, rituximab.
Immunity
According to Dalia Akramien--- in the 2007 article, "Effects of Beta-glucans on the Immune System," beta-glucans have been known as powerful immune stimulants by scientists for at least the last 20 years. The glucans have broad-ranging effects in enhancing immunity. Akramiene notes that glucans are thought to mediate their effects by binding to and interacting with receptors on three different immune cells: macrophages, neutrophils and natural killer, or NK, cells, thereby enhancing the killing of microbial invaders. Due to their predominant presence in nature, in the form of fungi, yeasts, and mushrooms, beta-glucans have a specific cell-receptor on tissue macrophages by which they mediate their immune-boosting effects. Beta-glucan, itself, was found to elicit broad-range anti-infective effects against many bacteria as well as viruses, including the swine flu, explains Akramiene.
Cancer
Due to their immune-boosting qualities, beta-glucans have also been investigated for use in cancer. Cancer development involves four stages: initiation, promotion, progression and metastasis in which the cancer spreads to other parts of the body. The initiation and promotion stages are early stages which, according to the "Nutrition and Cancer Study Guide" by Anita Laswell, can be influenced by nutrition and lifestyle. Edible mushrooms such as Reishi, Tricholoma lobayense, Maitake and Sparassis cripsa, were found to undermine cancer growth and development in varying ways. The mushrooms suppressed signals that promoted and encouraged uncontrolled cell growth, increased tumor toxic immune cells, inhibited angiogenesis, or the building of new blood vessels to feed cancerous cells, and abated the side effect of red and white blood cell depletion, common to conventional radiation and chemotherapy. Furthermore, Akramiene notes that beta-glucan-rich mushrooms have been identified as adjunctive to chemotherapy, especially with use of the monoclonal antibody, or mAb, drugs. These drugs can be more effective than radiation or chemotherapy because they spare normal cells from damage. Even the superior effectiveness of these treatments can be improved with the use of beta-glucans.
Lowering Cholesterol
Oat bran has been established as beneficial in lowering cholesterol. The 1994 study, however, by J.T. Braaten, published in the European Journal of Clinical Nutrition, confirmed the hypothesis that it was the beta-glucan aspect of the oat bran that actually lowered cholesterol. The 1994 study was confirmed by a 2007 controlled clinical trial, in which participants were given 6g of beta-glucan per day for six weeks. The 2007 Clinical Journal article by Katie McQueen concluded that the 6g of beta-glucan lowered total and LDL cholesterol significantly more than the placebo control.
Diabetes Management
Processed and bleached foods versus whole, fiber-rich foods are implicated in the development of the insulin resistance that leads to diabetes. Whole, non-processed foods such as oat bran are high in the soluble fiber, beta-glucan. A 2002 European Journal of Clinical Nutrition study by A.L. Jenkins notes that when a regular oat bran cereal is enriched with a fractionated, concentrated dose of 12.5 percent beta-glucan, the ability to raise blood sugar was reduced by 62 percent. The viscosity and palatability decreases with such a high dose of glucans, so product development companies are currently researching ways to balance this effect.
References
- National Cancer Institute: Drug Dictionary---Beta Glucan
- American Cancer Society: Maitake Mushroom
- Medicina: "Effects of beta-glucans on the immune system"
- "Nutrition and Cancer Study Guide"; Anita Laswell, M.D.; 1998
- European Journal of Clinical Nutrition: "Oat beta-glucan reduces blood cholesterol concentration in hypercholesterolemic subjects"
