Nutrition Facts and Potential Benefits of Shiitake Mushroom  | Shiitake Benefits for Health and Wellness | Benefits and Uses of Shiitake Mushrooms Shiitake's food value alone makes the mushroom a welcomed contribution to our increasingly diet-conscious world. Shiitake is a good source of protein, potassium, and, including the stems, zinc, an important element for immune competence. It is also a rich source of complex carbohydrates called polysaccharides and contains more than one that is known to potentiate the immune system, a subject we will take up in later chapters. If all these factors seem a lot for one mushroom, that is not surprising; mushrooms are a neglected source of human nutrition. When one considers that they can be produced on waste materials—converting products of little or no market value into food for an over-populated world—then there is no doubt that mushrooms represent one of the world's greatest untapped resources of nutritious and palatable food for the f