The healthiest way to cook mushrooms is to microwave or grill them to preserve their goodness, researchers say. These cooking methods significantly increase levels of antioxidants which protect cells against diseases, but boiling or frying reduces them. A study, from Spain, looked at the properties of four different types of mushrooms before and after cooking. Adding a little oil when grilling can even improve the nutritional value of the mushrooms. Plenty, it turns out. They contain protein, including essential amino acids, fibre and lots of vitamins – such as B, C , D and E. They are also low in calories and fat. In this study, published in the International Journal of Food Sciences and Nutrition, researchers analysed how cooking methods altered white button, shiitake, oyster and king oyster mushrooms. Frying resulted in protein and carbohydrates being lost from the mushrooms, as well as antioxidant compounds. Antioxidants are vitamins and chemicals that play a key role in protecting the body against free ra7dicals, which are linked to heart disease, cancer and other diseases. What happens is that they disappear into the oil in the frying pan, reducing the goodness of the mushrooms.