Updated on 6/28/2005
Beta glucans are a group of naturally occurring polysaccarides (complex sugars) that are part of the cell walls of bacteria, plants and fungi. As dietary supplements, they seem to boost immune function. They are also partly responsible for the anti-cancer and immune-boosting effects of medicinal mushrooms. A National Cancer Institute (www.nci.nih.gov) study showed that injecting tumors with glucan derivatives led to a reduction in their size. This was associated with migration of immune cells to the tumor site and with tumor necrosis (cell death). Beta glucan supplements are widely promoted on the Internet and sold through multi-level marketing schemes.
Rather than taking overpriced beta glucan supplements I suggest including mushrooms in your diet as a better way of getting their beneficial effects. I've often recommended certain species of mushrooms to cancer patients and cancer survivors:
- Maitake (Grifola frondosa). This delicious, edible mushroom is known as "hen of the woods" because it resembles the fluffed tail feathers of a nesting hen. In addition to its anti-cancer, anti-viral and immune-enhancing properties, maitake may also reduce blood pressure and blood sugar. You should be able to find it dried or fresh in Japanese markets, gourmet stores or upscale supermarkets.
- Shiitake (Lentinula edodes). This delicious, meaty-tasting mushroom is widely available fresh or dried in grocery stores and Asian markets. The Japanese have extensively studied the shiitake and found it to have immune modulating, anti-viral and cholesterol-reducing properties. Certain extracts of shiitake mushrooms are used in Japan as adjunctive therapy to strengthen immunity of cancer patients during chemotherapy and radiation.
- Agaricus (Agaricus blazei). This is a medicinal mushroom with anti-tumor and anti-viral activity widely used by oncologists in Japan and Brazil. It is delicious, and I hope it will become available here as a gourmet species. You can get it as a culture or in extract form from Fungi Perfecti (www.fungi.com) in Olympia, WA.
- Reishi (Ganoderma lucidum). Too woody and bitter to eat as food, reishi mushrooms are available in tea bags, capsules and liquid extracts. Animal studies have shown that reishi improves immune function and inhibits the growth of some malignant tumors. It is also a natural anti-inflammatory agent.
These, along with other well-studied medicinal mushrooms, may also be available as a blended product, and is probably your best bet for getting the most from beta glucans.
Andrew Weil, M.D.