Shiitake mushrooms are native to China and have been used in traditional medicine for more than 6000 years. Around the late 1990s, scientists began to discover the substances in shiitakes responsible for their antioxidant and immune-boosting benefits. Shiitakes are also a good source of dietary fiber, vitamins and minerals.
The shiitake, also called the Chinese black mushroom, is a large, golden to dark brown mushroom with an edible cap. Popular in Asian cuisine for centuries, it has gained popularity in the United States, where it’s added to salads, soups and pastas. It’s also meaty and flavorful enough to be used as the primary ingredient in sandwiches. Dried shiitakes can be stored in the freezer for up to six months.
The process of drying the shiitake mushroom improves its overall nutritional value. Just one example is vitamin D, which increases from 4 IU in one serving of raw mushrooms to 26 IU when dried. Some sources state that shiitakes provide 19 percent of the daily value (DV) of iron and 10 percent of the DV of vitamin C, protein and fiber. Although those values are accurate, they're based on 226 grams of mushrooms. A very generous serving size of four shiitake mushrooms only weighs 15 grams. Because this article includes nutrition information for one serving size, the values will be much smaller.
One serving has 44 calories, 3 percent DV of protein, 4 percent DV of total carbohydrates and an insignificant amount of fats and sugars. Shiitakes are a great source of dietary fiber; one serving provides 7 percent of your daily value.
The shiitake is an exceptional source of the B vitamin pantothenic acid (B5), which is essential for the body’s ability to convert food to energy and produce essential fats and neurotransmitters. In addition to providing 33 percent of the DV of pantothenic acid, shiitakes also supply other B vitamins, including riboflavin (11 percent), niacin (11 percent), vitamin B6 (7 percent), folate (6 percent) and thiamin (3 percent DV). The mushrooms also supply 1 percent of the daily value of vitamin C. Although one serving of dried mushrooms provides 26 IU of vitamin D, this is not enough to register as a percent of the DV.
Shiitakes are a great source of essential minerals, including copper (39 percent), selenium (10 percent) and manganese (9 percent DV). You’ll also gain 8 percent of the daily value of zinc, 7 percent of potassium, 5 percent of magnesium and 1 percent of iron.
Shiitakes contain several biochemicals, including eritadenine, L-ergothioneine and lentinan, that help to reduce cholesterol, work as antioxidants and boost the immune system. In the March 2003 issue of the Journal of Nutrition, Yasuhiko et al. reported that eritadenine helps to reduce cholesterol. Markove et al. studied L-ergothioneine and reported in the April 2009 issue of Free Radical Biology and Medicine that it is a “potent antioxidant” easily used at the cellular level. Other studies indicate that lentinan, which is a beta-glucan, stimulates the immune system and has the potential to reduce the growth of cancer cells.
Shiitake mushrooms contain natural substances called purines. They serve important functions in the body, but they also break down to form uric acid. You should limit your consumption of purines if you have kidney problems or gout.