High Cholesterol

Because of their high fibre content, sterols and low calorific value mushrooms are an ideal food for diets designed to prevent cardiovascular disease and have also been extensively investigated for their potential therapeutic application in this regard.

In animal models a range of mushrooms, including Agaricus bisporus (common button mushroom), Grifola frondosa, Lentinus edodes, Ganoderma lucidum and Flammulina velutipes, all show increased excretion of cholesterol, decreases in LDL and triglycerides and rises in HDL when included in the diet at 5% of feed1-4. Similar effects are seen from dietary inclusion of other beta glucan sources such as oats and barley and it is considered that the action of beta glucans on cholesterol levels is mediated by their binding affinity for bile acids, leading to activation of cholesterol 7α-hydroxylase and upregulation of low-density lipoprotien receptor and thus increased transport of LDL into hepatocytes and the conversion of cholesterol into bile acids5.

In addition, some mushrooms show specific cholesterol lowering action. Prominent among these is Pleurotus ostreatus (oyster mushroom), which is a natural source of the important cholesterol-lowering drug lovastatin (also called monakolin K, or mevinolin) wih higher levels found in the fruiting body (especially in the lamellae or gills) than the mycelium6. Inclusion of 15-20g/day dried P. ostreatus in the diet of hypercholesterolemic patients reduced cholesterol levels in many but not all patients while inclusion in the diet of rats at 1% produced no effect but 5% produced significant reductions in serum cholesterol, liver cholesterol and VLDL7. However, levels of Lovastatin show significant variation from one strain to another making standardised protocols difficult and better results are achieved clinically with another lovastatin-producing fungus, Monascus purpureus (Hong Qu Mi – Red Yeast Rice) for which standardised strains are available and for which a much greater impact on cholesterol levels has been demonstrated than achieved by the equivalent dosage of pure lovastatin, implying synergistic action between it and other compounds found in fungi.

Eritadenine, a compound isolated from L. edodes has also demonstrated strong cholesterol lowering properties and it has been suggested that this occurs by alteration of hepatic phospholipid metabolism through the inhibition of S-adenosylhomocysteine hydrolase, increased excretion and decomposition of ingested cholesterol and reduced excretion of VLDL. L. edodes fed at 10-50g/kg of diet led to significant decreases in both plasma cholesterol concentration and PC:PE ratio of liver microsomes in rats and eritadenine included at 50mg/kg diet had a similar effect8. In clinical trials dried L. edodes (9g/day) decreased serum cholesterol 7-10% in patients suffering from hypercholesterolemia and 90g/day fresh L. edodes (equivalent to 9g/day dried mushroom) led to a decrease in total cholesterol of 9-12% and triglycerides of 6-7%9.

Saito et al reported levels of eritadenine of 400-700mg/kg, although Enman et al suggest that the true level may be 10 times greater but without standardised strains levels of eritadenine in L. edodes are hard to quantify10,11. It has also been shown that stirring rather than shaking during mycellial fermentation can produce a five-fold increase in production of eritadenine implying significant potential variability in response to cultivation parameters12.

1. White button mushroom (Agaricus bisporus) lowers blood glucose and cholesterol levels in diabetic and hypercholesterolemic rats. Jeong S.C, Jeong Y.T, Yang B.K, Islam R, Koyyalamudi S.R, Pang G, Cho K.Y, Song C.H. Nutr Res. 2010;30(1):49-56.
2. Cholesterol-lowering effects of maitake (Grifola frondosa) fiber, shiitake (Lentinus edodes) fiber, and enokitake (Flammulina velutipes) fiber in rats. Fukushima M, Ohashi T, Fujiwara Y, Sonoyama K, Nakano M. Exp Biol Med (Maywood). 2001;226(8):758-65.
3. Maitake extracts and their therapeutic potential – A Review. Mayell M. Alt Med Rev, 2001;6:1.
4. Cholesterol-lowering properties of Ganoderma lucidum in vitro, ex vivo, and in hamsters and minipigs. Berger A, Rein D, Kratky E, Monnard I, Piguet-Welsch C, Hauser J, Mace K, Niederberger P. Lipids in Health and Disease 2004;3:2
5. Effect of high beta-glucan barley on serum cholesterol concentrations and visceral fat area in Japanese men – A randomised, double-blinded, placebo controlled trial. Shimizu C, Kihara M, Aoe S et al. Plant Foods Hum Nutr. 2008;63:21- 5
6. Pleurotus fruiting bodies contain the inhibitor of 3-hydroxy- 3-methylglutaryl-coenzyme A reductase – lovastatin. Gunde-Cimerman N, Cimerman A. Exp Mycol. 1995;19(1):1-6.
7. Dose and time dependent hypercholesterolemic effect of oyster mushroom (Pleurotus ostreatus) in rats. Nutrition. 1998;14:282-286.
8. Hypocholesterolemic action of eritadenine is mediated by a modification of hepatic phospholipid metabolism in rats. Sugiyama K, Akachi T, Yamakawa A. J Nutr. 1995;125(8):2134-44.
9. Shiitake (Lentinus edodes) Wasser S.P. Encyclopedia of Dietary Supplements. 2005 Epub
10. Quantitative analysis of eritadenine in “Shii-take” mushroom and other edible fungi. Saito M, Yamashita T, Kaneda T. Eiyo to Shokuryo. 1975;28:503-505.
v 11. Quantification of the bioactive compound eritadenine in selected strains of shiitake mushroom (Lentinus edodes). Enman J, Rova U, Berglund K.A. J Agric Food Chem. 2007;55(4):1177-80.
12. Production of the bioactive compound eritadenine by submerged cultivation of shiitake (Lentinus edodes) mycelia. Enman J, Hodge D, Berglund K.A, Rova U.J. Agric Food Chem. 2008;56(8):2609-12.

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