Fungal beta-glucans, along with beta-glucans from oats and barley, have been shown to help control blood glucose levels and it has been suggested that a possible mechanismis activation of P13K/Akt through binding to receptors including Dectin 1 and Scavenger1. However, daily supplementation of a normal diet with 3.5g/day beta-glucan in type II diabetics over 8 weeks failed to produce any change in fasting glucose levels2.

All the main medicinal mushrooms have been investigated for potential benefits in cases of diabetes with several modes of action proposed3.
Agaricus subrufescens – Consumption of 1.5g of polysaccharide extract in combination with metformin and gliclazide for 12 weeks reduced insulin resistance in patients with type II diabetes4.
Auricularia auricula – A water-soluble polysaccharide from A. auricularia at 3% of feed reduced fasting glucose levels and improved glucose tolerance in mice5.
Ophiocordyceps sinensis – Animal studies at a dose of 250mg/kg showed improved insulin sensitivity and reduced fasting blood glucose. In one clinical trial 3g/day of a proprietary O. sinensis preparation improved blood sugar control in 95% of patients compared to 54% of a control group treated by other methods6-8.
Ganoderma lucidum – Consumption of 5.4g of polysaccharide extract for 8 weeks produced a 13% reduction in blood sugar levels in patients with type II diabetes mellitus who were not taking insulin and also led to significant improvement in peripheral neuropathy in diabetic patients9,10.
Grifola frondosa – Improved glucose tolerance in diabetic rats at 20% of feed and in a separate experiment at 1g/day. A water soluble extract, X-fraction also increased insulin sensitivity11-13.
Hericium erinaceus – Blood sugar levels decreased by 19-26% in rats fed H. erinaceus extract at 100mg/kg14.
Pleurotus ostreatus – Reduced plasma glucose levels at 4% of feed and was reported to reduce blood glucose in diabetic patients at an unspecified dosage15,16.
Tremella fuciformis – 200mg/kg of a polysaccharide extract produced a 52% reduction in plasma glucose levels17.
Some practitioners report good results with Coprinus comatus but published research either relates to vanadium-enriched C. comatus or to high supplementation levels18-23.

O. sinensis biomass at a dose of 3-5g/day can be helpful for stabilising blood sugar levels in both insulin dependent and non-insulin dependent diabetes and in reducing diabetes-related depression.

1. Beta-glucans in the treatment of diabetes and associated cardiovascular risks. Chen J, Raymond K. Vasc Health Risk Manag. 2008;4(6):1265-72.
2. A controlled study of consumption of beta-glucan-enriched soups for 2 months by type 2 diabetic free-living subjects. Cugnet-Anceau C, Nazare J.A, Biorklund M, Le Coquil E, Sassolas A, Sothier M, Holm J, Landin-Olsson M, Onning G, Laville M, Moulin P. Br J Nutr. 2010;103(3):422-8.
3. Medicinal Mushrooms for Glycemic Control in Diabetes Mellitus: History, Current Status, Future Perspectives, and Unsolved Problems (Review). Lo HC, Wasser SP. Int J Med Mushr. 2011;13(5):401-426.
4. The mushroom Agaricus Blazei Murill in combination with metformin and gliclazide improves insulin resistance in type 2 diabetes: a randomized, double-blinded, and placebo-controlled clinical trial. Hsu CH, Liao YL, Lin SC, Hwang KC, Chou P. J Altern Complement Med. 2007;13(1):97-102.
5. Hypoglycemic effect of water-soluble polysaccharide from Auricularia auricula-judae Quel. on genetically diabetic KKAy mice. Yuan Z, He P, Cui J, Takeuchi H. Biosci Biotechnol Biochem. 1998;62(10):1898-903.
6. Clinical observations of adjunctive treatment of 20 diabetic patients with Jin Shui Bao capsule. Guo QC, Zhang C, Lo HC, Tu ST, Lin KC, Lin SC. J Admin Trad Chin Med. 1995; 5:223.
7. The anti-hyperglycemic activity of the fruiting body of Cordyceps in diabetic rats induced by nicotinamide and streptozotocin. Lo HC, Tu ST, Lin KC, Lin SC. Life Sci. 2004;74(23):2897-908.
8. CordyMax Cs-4 improves glucose metabolism and increases insulin sensitivity in normal rats. Zhao CS, Yin WT, Wang JY, Zhang Y, Yu H, Cooper R, Smidt C, Zhu JS. J Altern Complement Med. 2002;8(3):309-14.
9. A phase I/II study of Ling Zhi mushroom Ganoderma lucidum (W.Curt.:Fr.) Lloyd (Aphyllophoromycetideae) extract in patients with type II Diabetes mellitus. Gao Y, Lan J, Dai X, Ye J, Zhou S. Int J Med Mushr. 2004;6(1).
10. A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia. Tang W, Gao Y, Chen G, Gao H, Dai X, Ye J, Chan E, Huang M, Zhou S. J Med Food. 2005;8(1):53-8.
11. Anti-diabetic activity present in the fruit body of Grifola frondosa (Maitake). Kubo K, Aoki H, Nanba H. I. Biol Pharm Bull. 1994;17(8):1106-10.
12. Maitake (Grifola frondosa) improve glucose tolerance of experimental diabetic rats. Horio H, Ohtsuru M. J Nutr Sci Vitaminol (Tokyo). 2001;47(1):57-63.
13. Antihypertensive and metabolic effects of whole Maitake mushroom powder and its fractions in two rat strains. Talpur NA, Echard BW, Fan AY, Jaffari O, Bagchi D, Preuss HG. Mol Cell Biochem. 2002;237(1-2):129-36.
14. Hypoglycemic effect of extract of Hericium erinaceus. Wang JC, Hu SH, Wang JT, Chen KS, Chia YC. Journal of the Science of Food and Agriculture. 2005;85(4):641-646.
15. Effect of the oyster fungus on glycaemia and cholesterolaemia in rats with insulin-dependent diabetes. Chorváthová V, Bobek P, Ginter E, Klvanová J. Physiol Res. 1993;42(3):175-9.
16. Oyster mushroom reduced blood glucose and cholesterol in diabetic subjects. Khatun K, Mahtab H, Khanam PA, Sayeed MA, Khan KA. Mymensingh Med J. 2007;16(1):94-9.
17. Hypoglycemic effects of exopolysaccharides produced by mycelial cultures of two different mushrooms Tremella fuciformis and Phellinus baumii in ob/ob mice. Cho EJ, Hwang HJ, Kim SW, Oh JY, Baek YM, Choi JW, Bae SH, Yun JW. Appl Microbiol Biotechnol. 2007;75(6):1257-65.
18. Effect of Coprinus comatus on plasma Glucose concentrations in mice. Bailey CJ, Turner SL, Jakeman KJ, Hayes WA. Planta Med. 1984;50(6):525-526.
19. Vanadium uptake by biomass of Coprinus comatus and their effect on hyperglycemic mice. Han C, Cui B, Wang Y. Biol Trace Elem Res. 2008;124(1):35-9.
20. Comparison of vanadium-rich activity of three species fungi of basidiomycetes. Han C, Cui B, Qu J. Biol Trace Elem Res. 2009;127(3):278-83.
21. Comparison of hypoglycemic activity of trace elements absorbed in fermented mushroom of Coprinus comatus. Lv Y, Han L, Yuan C, Guo J. Biol Trace Elem Res. 2009;131(2):177-85.
22. Hypoglycemic activity of fermented mushroom of Coprinus comatus rich in vanadium. Han C, Yuan J, Wang Y, Li L. J Trace Elem Med Biol. 2006;20(3):191-6.
23. Determination of trace elements in three mushroom samples of Basidiomycetes from Shandong, China. Wang C, Hou Y. Biol Trace Elem Res. 2010 Jul 28.