maitake mushroom maitake mushroom (Grifola frondosa) Mushroom Capsules. Maitake is rich in minerals such as potassium, calcium, and magnesium. Contains various vitamins B2, D2 and niacin, fibers and amino acids. Maitake ‘The Dancing Mushroom’ is traditionally regarded as the mushroom for a healthy immune system. Contents – maitake mushroom recipes