Maitake Extracts and Their Therapeutic Potential — A Review

Alternative Medicine Review, Feb, 2001 by Mark Mayell

Weight Control

Maitake provides some B vitamins, ergosterol/provitamin D2, magnesium, potassium, calcium, unsaturated fatty acids, phosphatidylserine and other phospholipids, and protein. Maitake does not contain vitamins A or C although substances with chemical properties similar to ascorbic acid have been identified in maitake.[46] Because maitake is rich cited as a potential weight-loss aid. Animal studies have shown that maitake as a major component of the diet can inhibit weight gain. When rats were fed dried maitake powder as 20 percent (by weight) of a high-cholesterol diet, it significantly inhibited increases in body weight and body fat.[43] A similar protocol promoted improved fat metabolism among maitake-fed rats. Maitake-fed rats weighed 24.9-percent less than control rats at the end of the study.[44] Feeding tests conducted on spontaneously hypertensive rats showed a weight-inhibiting effect for maitake.[47] In a preliminary clinical study conducted on 30 overweight patients, researchers gave subjects maitake tablets equal to 200 g fresh maitake daily for two months. Even though subjects made no changes to their regular diets, all lost weight. Average weight loss was 7-13 pounds, and one subject lost 26.4 pounds. A few patients reported slightly looser stools as a side effect.[48]

Dosage

Further research may help clarify issues relating to dosage. Data from feeding studies done on animals fed a 5-20 percent maitake diet by weight are difficult to apply to humans, since such a maitake-rich diet would be difficult for most people to follow. One recent animal study investigated the clearance of two kinds of glucans (GRN from Grifola frondosa and SSG from Sclerotinia sclerotiorum) from the blood following multiple dosing of mice with an autoimmune disease. Researchers administered 250 mcg once per week intraperitoneally to mice for 35 weeks. Blood glucan concentrations were determined to be high (about 20 mcg/mL for GRN and 200 mcg/mL for SSG). The researchers concluded, "These findings suggest that administration of a large quantity of the glucan saturated the reticuloendothelial system, resulting in circulation of the glucan in the blood."[49]

In his discussion of maitake dosing in Medicinal Mushrooms,[50] Hobbs notes that oral doses of the D-fraction that have been shown to be effective as antitumor and immunopotentiating agents in mice are approximately 0.75 mg/kg of mouse weight. He notes, "Although it is difficult to compare the activity in mice with humans, assuming a 1:1 activity ratio would mean that a comparable dose of D-fraction, found in the quantity of 4 mg/g of fruit body, is 47.25 mg for a 140-pound person--the amount contained in about 11.81 grams of maitake fruiting body." One product manufacturer says the therapeutic amount of maitake D-fraction is from 0.5mg to 1.0 mg/kg of body weight per day. That would amount to an approximate daily dose of 35-70 mg of the D-fraction.

Commercial preparations of the D- and MD-fractions typically provide 3- 25 mg of the standardized extract along with 75-250 mg of the whole powder per capsule. Capsules of the whole powder typically range in size from 100-500 mg. Liquid extracts are also available, some standardized, for example, for 1 mg D-fraction per drop. Some capsule products are also concentrated and standardized for a minimum (such as 30 percent) of polysaccharides, including the beta-D-glucan fraction. Typical label-recommended daily disease-preventive doses range from 12-25 mg extract/200-250 mg whole powder, and 500-2,500 mg whole powder.