The stress and pressure of modern society take a toll on immune system health. Those with weakened immunity are more susceptible to infection and disease.

The need to maintain or rebuild a healthy defense has led researchers to minerals, plants and fungi in search of natural health-supporting properties. The fungi family in particular shows promise for its ability to enhance immune function.

Mushrooms grow wild in many parts of the world and are also commercially cultivated. Nutritionally, mushrooms are a valuable health food—low in calories and carbohydrates; healthy in vegetable proteins and essential amino acids; a source of some fiber; and rich in a number of important vitamins and minerals, including B vitamins, selenium, iron, potassium and zinc.1

Mushrooms have been used medicinally for centuries in traditional Chinese and Japanese medicine. In many Asian cultures, mushrooms are used to promote good health and vitality and to increase the body's adaptive capabilities. Although the nutritional facts and culinary uses of mushrooms are well-accepted in the West, the fungi's medicinal qualities have yet to make the mainstream.

Of the hundreds of known mushroom varieties, several have been studied for their ability to enhance the human immune system and fight infections. Some well-known medicinal mushrooms with benefits for the immune system include reishi (Ganoderma lucidum) shiitake (Lentinus edodes), maitake (Grifola frondosa) and cordyceps (Cordyceps sinensis). Some of the less familiar mushrooms include bai mu erh (Tremella fuciformis), fu ling (Poria cocos), zhu ling (Grifola umbellata), lion's mane (Hericium erinaceus), Auricularia auricula-judae and Coriolus versicolor.^2,3^,4^,5,6

Researchers recently studied some of the isolated chemicals from a number of Basidiomycetes mushrooms—a large group of fungi whose members range from the familiar button mushroom to rusts and smuts that sometimes ravage crops. The constituents show promising immune-modulating, antibacterial, antiviral, antitumor, antiparasitic, cardiovascular and hypercholesterolemic effects.7^,8^,9^,10 In fact, mushrooms have an impressive effect on the cardiovascular system. Researchers have found that numerous varieties such as maitake, shiitake and cordyceps can reduce total cholesterol levels, reduce the "bad" cholesterol (low-density lipoproteins) and triglycerides, decrease platelet binding, and reduce arterial pressure.¹¹ Mushrooms also can affect glycemic levels and inflammatory conditions.12

In addition to these promising preliminary findings, scientists have also noted that mushrooms have definite primary and secondary physiological effects on the human immune system. Israeli researchers noted in 1999 that cellular components and secondary metabolites of many mushrooms affect the immune system of the host and therefore could be used to treat a variety of disease states.13

Medicinal mushrooms' powerful immune-modulating and potentiating activity helps support and enhance overall immune function. Researchers are also finding that mushrooms can directly stimulate both the basic (lymphocyte, neutrophils, etc.) and secondary immune responses (immunoglobulins IgE, IgA, IgG) of the immune system. This leads to increased production of immune defenders such as macrophages and cytokines, which play vital roles in recognizing and removing foreign antigens, as well as releasing chemical mediators including interleukin-1.

In recent studies on medicinal mushrooms, researchers have used modern analytical and laboratory techniques to significantly improve isolation and identification of bioactive chemicals. These techniques have revealed mushroom substances with antimicrobial activity. A 1999 study in Japan found three kinds of antibacterial substances in shiitake mushrooms that were effective against Streptococcus spp., Actinomyces spp., Lactobacillus spp., Prevotella spp. and Porphyromonas spp. of oral origin.14 A study in Spain found that 45 percent of 317 isolated (extracted) substances from 109 polypore and gilled mushroom species showed antimicrobial activity.15 Some mushrooms have generalized antimicrobial effects, while others have quite specific properties. This dual capability is important because it provides two separate methods of immune enhancement and response, which is important for treating specific microbial infections such as gram-negative streptococcal and herpetic virus microbial infections and disease states such as sarcoma cancers, leukemia and hepatitis.

Substances that have been found to potentiate the immune system include beta-glucans, lentins, polysaccharides, polysaccharide-peptide complexes, triterpenoids, nucleosides and other secondary metabolites.16^,17^,18,19 Many of these bioactive substances, through their stimulatory effects on the immune system, are showing powerful antitumor, antimutagenic and anticancer activity.20

Beta-glucan is isolated from shiitake and maitake mushrooms,²¹ as well as from yeast cell walls22^,23 and from oat and barley bran.²⁴ It has 1,3- and 1,6-glucose links. The 1,3 refers to the sites at which glucose molecules are connected to form the glucan backbone. The 1,6 refers to the bonding sites between a glucose molecule on the backbone and on the side chains.

Beta-glucan binds to macrophages and other phagocytic white blood cells at certain receptors and activates their anti-infection and antitumor activity by stimulating free-radical production.²⁵ This in turn signals the phagocytic immune cells to engulf and destroy foreign bodies, be they bacteria, viruses or tumor cells.26

Three separate multicenter, randomized, double-blind, placebo-controlled clinical trials have been conducted—two at Harvard Medical School—using beta-glucan on patients undergoing high-risk major abdominal and thoracic surgery or high-risk gastrointestinal surgery. Patients in one study who received high-dose beta-glucan (2.0 mg/kg) had significantly fewer postoperative infectious complications compared with placebo.27 In another, beta-glucan patients experienced 1.4 infections per patient vs. 3.4 infections in the placebo group.28 In the third study, of 1,249 patients, beta-glucan patients had a statistically significant 39 percent reduction in serious infections and death compared with placebo.29 The investigators concluded that beta-glucan was safe and well-tolerated and could potentially decrease postoperative infections.

Medicinal mushrooms' potential tumor-inhibiting effects have led to a recent surge of research in this particular area.30^,31 In a 1999 study in Japan, researchers isolated a polysaccharide from the mushroom hime-matsutake (Agaricus blazei Murrill) that proved to have antitumor effects against sarcoma 180.32 In a mouse study, other researchers investigated the antimutagenic effects of the same mushroom. They concluded that antimutagenic activities of hime-matsutake, under certain circumstances, might contribute to its anticarcinogenic effect.33

Umbrella Of Protection
The growing body of scientific evidence indicates that mushroom extracts and derivatives support the immune system. For wellness and general health effects, I recommend a combination of mushroom products (vs. a single mushroom type), preferably from an extract rather than an unprocessed whole mushroom. Certainly, incorporating whole mushrooms in the diet is important, but to achieve greater and more specific immune enhancement, standardized extracts are needed. A combination of different medicinal mushrooms offers both the generalized and specific immune system benefits. For example, a formula that includes some combination of reishi, shiitake, cordyceps, fu ling, lion's mane, bai mu erh, and zhu ling extracts can be taken frequently or even daily to enhance the immune system. As powerful immune modulators and potentiators, medicinal mushrooms are contraindicated for a number of autoimmune conditions such as systemic lupus erythematosus and collagen autoimmune disorders.

Medicinal mushrooms' value to human health is beginning to gain acceptance. Researchers are providing crucial data on the array of bioactive chemicals found within these fascinating fungi. More research is certainly warranted, but it appears mushrooms hold potential for improving human health and immunity.

Raymond M. Lombardi, D.C., C.C.N., is a certified herbalist with a holistic practice in Redding, Calif. He is author of Aspirin Alternatives—The Top Natural Pain-Relieving Analgesics (BL Publications, 1999).

References

1. Mattila P, et al. Contents of vitamins, mineral elements, and some phenolic compounds in cultivated mushrooms. J Agric Food Chem 2001 May;49(5):2343-8.

2. Kawagishi, et al. Erinacines A, B, C, strong stimulators of nerve growth factor synthesis, from the myczlia of Hericium erinaceum. Tetrahedron Letters 1994;35(10):1569-72.

3. Yu SJ, Tseng J. Fu-ling, a Chinese herbal drug, modulates cytokine secretion by human peripheral blood monocytes. Int J Immunopharmacol 1996 Jan;18(1):37-44.

4. Zee-Cheng RK. Shi-quan-da-tang (ten significant tonic decoction); SQT. A potent Chinese biological response modifier in cancer immunotherapy, potentiation and detoxification of anticancer drugs. Methods Findings Exp Clin Pharmacol 1992 Nov;14(9):725-36.

5. Gordon M, et al. A placebo-controlled trial of the immune modulator, lentinan, in HIV-positive patients: a phase I/II trial. J Med 1998;29(5-6):305-30.

6. Chang ST, Buswell JA. Ganoderma lucidum—a mushrooming medicinal mushroom. Intl J Medicinal Mushrooms 1999;1:139-46.

7. Ishikawa NK, Fukushi Y, et al. Antimicrobial cuparene-type sesquiterpenes, enokipodins C and D, from a mycelial culture of Flammulin velutipes. J Nat Prod 2001 Jul;64(7): 932-34.

8. Shon YH, Nam KS. Antimutagenicity and induction of anticarcinogenic phase II enzymes by basidiomycetes. J Ethnopharmacol 2001 Sep;77(1):103-9.

9. Fukushima M, Ohashi T, et al. cholesterol-lowering effects of Maitake (Grifola frondosa) fiber, shiitake (Lentinus edodes) fiber, and enokitake (Flammulina velutipes) fiber in rats. Exp Biol Med (Maywood) 2001 Sep;226(8):758-65.

10. Suay I, Arenal F, Asensio FJ, et al. Screening of basidiomycetes for antimicrobial activities. Antonie Van Leeuwenhoek 2000 Aug;78(2):129-3

11. Francia CS, et al. Current research finding on the effects of selected mushrooms on cardiovascular diseases. Intl J Medicinal Mushrooms 1999;1:169-72.

12. Zhu JS, et al. The scientific rediscovery of a precious ancient Chinese herbal regimen: Cordyceps sinesis: part II. J Altern Complement Med 1998 winter;4(4):429-57.

13. Wasser SP, Weis AL. Therapeutic effects of substances occurring in higher Basidiomycetes mushrooms: a modern perspective. Crit Rev Immunol 1999;19(1):65-96.

14. Hirasawa M, et al. Three kinds of antibacterial substances from Lentinus edodes (Berk.) Sing. (Shiitake, an edible mushroom). Int J Antimicrob Agents 1999 Feb;11(2):151-7.

15. Suay I, et al. Screening of basidiomycetes for antimicrobial activities. Antonie Van Leeuwenhoek 2000 Aug;78(2):129-39.

16. Zhu M, et al. Triterpene antioxidants from Ganoderma lucidum. Phytother Res 1999;13(6):529-31.

17. Eo S, et al. Antiherpetic activities of various protein bound polysaccharides isolated from Ganoderma lucidum. J Ethnopharmacol 1999;68(1-3):175-81.

18. Lui M, et al. Induction of immunomodulating cytokines by a new polysaccharide-peptide complex from culture mycelia of Lentinus edodes. Immunopharmacology 1998 Nov;40(3):187-98.

19. Ooi VE, Liu F. Immunomodulation and anti-cancer activity of polysaccharide-protein complexes. Curr Med Chem 2000 Jul;7(7):715-29.

20. Borchers AT, et al. Mushrooms, tumors, and immunity. Proc Soc Exp Biol Med 1999 Sep;221(4):281-93.

21. Mizuno T, et al. Antitumoractive substances from mushrooms. Food Rev Int 1995;11:23-6.

22. Tokunaka K, et al. Immunological and immunotoxicological activities of a water soluble 1-3 beta D glucan, CSBG, from a Candida spp. Int J Immunopharmacol 2000;22:383-94.

23. Bacon J, et al. The glucan component of the cell wall of baker's yeast (Saccharomyces cerevisiae) considered in relation to its ultrastructure. Biochem J 1969;114:557-67.

24. Baur SK, Geisler G. Variability of the beta-glucan content in oat caryopsis of 132 cultivated oat genotypes and 39 wild oat genotypes. J Agr Crop Sci 1996;176:151-7.

25. Adachi Y, et al. The effect enhancement of cytokine production by macrophages stimulated with 1,3 beta D glucan, grifolan, isolated from Grifola frondosa. Biol Pharm Bull 1994;17:1554-60.

26. Ohno N, et al. Effect of beta-glucan on the nitric oxide synthesis of peritoneal macrophage (sic) in mice. Biol Pharm Bull 1996;19:608-12.

27. Babineau TJ, et al. A phase II multicenter double-blind randomized placebo-controlled study of three dosages of an immunomodulator (PGG-glucan) in high-risk surgical patients. Arch Surg 1994;129:1204-10.

28. Babineau TJ, et al. Randomized phase I/II trial of a macrophage-specific immunomodulator (PGG-glucan) in high-risk surgical patients. Ann Surg 1994;220:601-9.

29. Dellinger EP, et al. Effect of PGG glucan on the rate of serious postoperative infection or death observed after high-risk gastrointestinal operations. Betafectin Gastrointestinal Study. Arch Surg 1999;13:977-83.

30. Wang JC, et al. Antimutagenicity of extracts of Hericium erinaceus. Kaohsiung J Med Sci 2001 May;17(5):230-8.

31. Fujimiya Y, et al. Tumor-specific cytocidal and immunopotentiating effects of relatively low molecular weight products derived from the basidiomycete, Agaricus blazei Murrill. Anticancer Res 1999 Jan-Feb;19(1A):113-8.

32. Mizuno M, et al. Anti-tumor polysaccharide from the mycelium of liquid cultured Agaricus blazei mill. Biochem Mol Biol Int 1999 Apr;47(4):707-14.

33. Delmanto RD, de Lima PL, et al. Antimutagenic effect of Agaricus blazei Murrill mushroom on the genotoxicity induced by cyclophosphamide. Mutat Res 2001 Sep 20;496(1-2):15-21.

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Natural Foods Merchandiser volume XXIII/number 9/p. 38

Natural Foods Merchandiser volume XXIII/number 9/p. 40