Mushrooms are a rich, low calorie source of fiber, protein, and antioxidants. They may also mitigate the risk of developing serious health conditions, such as Alzheimer’s, heart disease, cancer, and diabetes.  Mushrooms not only provide you with B vitamins such as niacin and riboflavin, but are also excellent sources of three essential antioxidants, glutathione, ergothioneine, and selenium. Additionally, they are an excellent source of vitamin D and potassium.