Well, that's how they're classified in the food groups. There's no sense in giving "edible fungi" their own category, is there?
While they're not nearly as nutrient-dense as many other types of vegetables, mushrooms do tend to have a good supply of copper -- a key nutrient not widely found in substantial amounts in other foods. They also aren't bad sources of potassium, folate, niacin, fiber and selenium. And, prepared properly, they can be a tasty, satisfying, low-calorie meat substitute.
If you're curious about the details regarding different types of mushrooms, you're in luck: The U.S. Department of Agriculture has added nutrient data for seven different kinds of mushrooms to its National Nutrient Database. Now you can compare and contrast the relative nutritional merits of crimini, enoki, maitake, oyster, portabella, shiitake and white button mushrooms.
If you look, you'll see that not all mushrooms are created equal. For example, shiitake mushrooms have a relatively high amount of copper -- nearly 1 milligram per 3.5 ounces of raw mushroom, compared with crimini (a half-milligram per 3.5 ounces of raw mushrooms); portabella (less than a half milligram per 3.5 ounces); white button mushrooms (about one-third of a milligram per 3.5 ounces); maitake and oyster (about one-quarter of a milligram) and enoki mushroom (less than 0.1 milligram copper per 3.5 ounces). The Recommended Dietary Allowance for copper in adults is 900 micrograms (or 0.9 milligrams) of copper a day. Research suggests that getting enough copper can be important to heart health.
Now, 3.5 ounces of raw mushrooms is a lot of mushrooms. If you consume all your mushrooms from canned mushroom soup or by sprinkling a few slices on your salad, you won't get much copper or anything else. But you could use mushrooms as your main dish. Portabella caps are often grilled and served like a hamburger. Or you can chop any kind of mushroom and substitute it for half (or more) of the burger or sausage in casseroles, sauces or stews.
As the water cooks out of mushrooms, the nutrients (and calories) become more concentrated. But at 20 to 50 calories per 3.5 ounces raw, mushrooms can add bulk and flavor to a dish with very few calories.
Different types of mushrooms have distinct flavors. Try new ones occasionally to see what works best for your recipes, and your palate.
This article is a service of Chow Line -- Ohio State University Extension and the Ohio Agricultural Research and Development Center.
All photos courtesy of istockphoto.com