Shiitake Mushrooms: Nutrition, Benefits and Side Effects

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Shiitake mushrooms are one of the most widely eaten mushrooms in the world, prized for their rich, savory flavor in soups, stir-fries and broths. Here is what shiitake mushrooms are, their nutrition, what the research says about their benefits, the side effects to know about, and how to eat them safely.

What you'll learn

• What shiitake mushrooms are and their nutrition facts
• What the research shows about shiitake benefits
• Shiitake side effects, including shiitake dermatitis
• How to cook and eat shiitake safely

What are shiitake mushrooms?

Shiitake (Lentinula edodes) is a mushroom native to East Asia that is now cultivated around the world. Both fresh and dried shiitake are staples of East Asian cooking (Memorial Sloan Kettering). They have brown, umbrella-shaped caps, firm, meaty flesh and a deep, savory (umami) flavor that gets stronger when they are dried.

Shiitake also contains lentinan, a type of polysaccharide (a beta-glucan) that is thought to be behind many of the effects researchers study (Memorial Sloan Kettering). Most of that research uses concentrated extracts rather than the mushrooms you cook at home.

Shiitake mushroom nutrition facts

Approximate nutrition in 1 cup (145 g) of cooked shiitake pieces, from USDA FoodData Central, with the percentage of the Daily Value (FDA):

In other words, a cup of cooked shiitake covers more than a full day's copper and about a full day's pantothenic acid, and about 65% of your selenium, for very few calories. It is also a source of fiber, zinc and several other B vitamins.

Shiitake has only a little vitamin D: about 0.4 mcg per 100 g raw (USDA FoodData Central). Some mushrooms are exposed to ultraviolet light to increase their vitamin D (NIH Office of Dietary Supplements), so check the label if that matters to you. Dried shiitake is much more concentrated by weight, but you use far less: four dried mushrooms weigh about 15 grams (USDA FoodData Central).

Shiitake mushroom benefits: what the research shows

Shiitake is a nutritious food, but research on specific health benefits in people is still limited. Here is what has been studied:

• Nutrients. The clearest benefit is nutritional: shiitake is low in calories and rich in copper, pantothenic acid and selenium (USDA FoodData Central).
• Immune markers. In a study of 52 healthy adults aged 21 to 41, eating 5 or 10 grams of dried shiitake a day for 4 weeks was followed by more active immune cells (gamma-delta T cells and NK-T cells), higher levels of an antibody in saliva (sIgA) and lower C-reactive protein, a marker of inflammation (Dai et al., 2015). The study was small and short, and it compared two doses without a placebo group, so it cannot prove cause and effect.
• Cholesterol and gut bacteria. Small randomized studies have looked at shiitake in adults with borderline or high cholesterol, including effects on blood lipids and gut bacteria (Memorial Sloan Kettering). These are early findings, and more research is needed.
• Lentinan. Lab and animal studies of shiitake extracts and lentinan show effects on immune activity, and lentinan has been studied alongside medical treatment in people with cancer. Memorial Sloan Kettering notes that more well-designed studies are needed (Memorial Sloan Kettering). These are concentrated extracts, not the amounts you get from eating mushrooms, and shiitake is not a treatment for any disease.

For a broader look at mushrooms and their evidence, see what the evidence says about functional mushrooms.

Shiitake side effects

Cooked shiitake is a common food that most people eat without problems. These are the side effects that have been reported (Memorial Sloan Kettering):

• Shiitake dermatitis. An itchy, whip-like rash, described below, usually after eating raw or undercooked shiitake.
• Allergic reactions. Food allergy to shiitake has been reported, and people who breathe in large amounts of shiitake spores, such as mushroom growers, can develop a lung reaction called hypersensitivity pneumonitis.
• Problems with long-term shiitake powder. Rash, sun sensitivity, digestive upset and a rise in eosinophils (a type of white blood cell) have been reported after taking shiitake powder for a long time.
• Bowel blockage. Rarely, swallowing a whole shiitake, or several large pieces, has blocked the small intestine. Slice them and chew well.

What is shiitake dermatitis?

Shiitake dermatitis (also called flagellate dermatitis) is a rare skin reaction to lentinan. It causes streaks of red, raised, itchy lines that look like whip marks. In a review of 50 reported cases, almost all (98%) had this whip-like rash and 78% had itching; some also had fever, diarrhea or mouth sores (Nguyen et al., 2017).

Most cases followed eating raw shiitake, and 22% followed eating lightly cooked or undercooked shiitake (Nguyen et al., 2017). The rash usually goes away on its own in about 12.5 days, and the main advice is to avoid eating shiitake that way again (Nguyen et al., 2017). If you develop a rash with fever or mouth sores, see a health care provider.

How to cook and eat shiitake safely

1. Cook them thoroughly. Because most cases of shiitake dermatitis follow raw or undercooked shiitake (Nguyen et al., 2017), skip raw shiitake in salads and cook them until tender and browned.
2. Trim the stems. Shiitake stems are tough and woody. Remove them from the caps and save them for stock.
3. Slice and chew well. Slicing them helps them cook evenly and avoids swallowing large pieces (Memorial Sloan Kettering).
4. Rehydrate dried shiitake. Soak them in warm water until soft, then use them like fresh. The soaking liquid adds savory flavor to soups and sauces.

Easy ways to use them: sauté with garlic and soy sauce, add to stir-fries, noodle soups and miso soup, or roast until crisp at the edges. For another meaty mushroom, see how to cook lion's mane mushrooms.

Shiitake supplements and mushroom blends

Shiitake also shows up in capsules, powders and mushroom blends such as mushroom matcha. Extracts and powders are different from the cooked mushroom: long-term use of shiitake powder has been linked to rash, sun sensitivity and digestive upset (Memorial Sloan Kettering). If you are pregnant or breastfeeding, take medication or have a medical condition, talk to your health care provider before taking a mushroom supplement. To compare products, see how to choose a quality mushroom extract.

Common myths (quick reality check)

• Myth: Raw shiitake is fine in salads. Reality: Raw or undercooked shiitake is the most common trigger of shiitake dermatitis, an itchy, whip-like rash. Cook them well.

• Myth: Shiitake is a good source of vitamin D. Reality: Regular shiitake has only a little vitamin D. Mushrooms exposed to ultraviolet light can have more; check the label.

• Myth: Eating shiitake can treat cancer. Reality: Lentinan, a compound in shiitake, has been studied as a concentrated extract alongside medical treatment, and more research is needed. Eating shiitake is not a treatment for cancer or any other disease.

Frequently asked questions (FAQ)

Are shiitake mushrooms healthy?

Yes. A cup of cooked shiitake has about 81 calories and provides about 144% of the Daily Value for copper, 104% for pantothenic acid and 65% for selenium, plus fiber and other B vitamins.

What are the benefits of shiitake mushrooms?

Shiitake is rich in nutrients like copper, pantothenic acid and selenium. A small study found that eating dried shiitake daily for 4 weeks was followed by changes in immune markers, but more research is needed.

Can you eat shiitake mushrooms raw?

It is best not to. Most cases of shiitake dermatitis, an itchy, whip-like rash, follow eating raw or undercooked shiitake. Cook them until tender.

What is shiitake dermatitis?

A rare skin reaction to lentinan in shiitake that causes itchy, red, whip-like streaks, usually after eating raw or undercooked shiitake. It typically clears on its own in about 12.5 days.

Do shiitake mushrooms have vitamin D?

Only a little, about 0.4 mcg per 100 g raw. Mushrooms exposed to ultraviolet light can have more.

Can you eat shiitake stems?

The stems are tough and woody, so most people remove them and use them to flavor stock or broth.

What are the side effects of shiitake mushrooms?

Most people eat cooked shiitake without problems. Reported side effects include shiitake dermatitis, food allergy, lung reactions in people who inhale spores, digestive upset with long-term shiitake powder and, rarely, bowel blockage from swallowing large pieces.

Related guides

• King Trumpet Mushrooms: What They Are and Their Benefits
• Lion's mane mushroom supplement guide
• Reishi mushroom benefits and side effects
• Turkey tail mushroom benefits
• What is cordyceps?
• Mushroom matcha: what it is
• Mushroom coffee side effects

Disclaimer and when to seek help

This article is for general education and is not medical advice. These statements have not been evaluated by the Food and Drug Administration. Our products are not intended to diagnose, treat, cure, or prevent any disease. See a health care provider if you develop a rash, fever, mouth sores or trouble breathing after eating or handling mushrooms, and talk to your provider before taking a mushroom supplement if you are pregnant or breastfeeding, take medication or have a medical condition.

References

1. U.S. Department of Agriculture. FoodData Central (SR Legacy: mushrooms, shiitake, cooked, without salt; raw; dried).
2. U.S. Food and Drug Administration. "Daily Value on the Nutrition and Supplement Facts Labels."
3. Memorial Sloan Kettering Cancer Center. "Shiitake Mushroom." About Herbs, last updated February 14, 2023.
4. Nguyen AH, Gonzaga MI, Lim VM, et al. "Clinical features of shiitake dermatitis: a systematic review." International Journal of Dermatology, 2017;56(6):610-616. doi:10.1111/ijd.13433
5. Dai X, Stanilka JM, Rowe CA, et al. "Consuming Lentinula edodes (shiitake) mushrooms daily improves human immunity: a randomized dietary intervention in healthy young adults." Journal of the American College of Nutrition, 2015;34(6):478-487. doi:10.1080/07315724.2014.950391
6. NIH Office of Dietary Supplements. "Vitamin D: Fact Sheet for Consumers."