What Are Shiitake Mushrooms?

Shiitake are edible mushrooms native to East Asia.

They're tan to dark brown, with caps that grow between 2 and 4 inches (5 and 10 cm).

While typically eaten like vegetables, shiitake are fungi that grow naturally on decaying hardwood trees.

Around 83% of shiitake are grown in Japan, although the United States, Canada, Singapore, and China also produce them (1).

You can find them fresh, dried, or in various dietary supplements.

Summary

Shiitake mushrooms are brown-capped mushrooms used around the world for food and as supplements.

Nutrition Profile of Shiitake Mushrooms

Shiitake are low in calories. They also offer good amounts of fiber, as well as B vitamins and some minerals.

The nutrients in 4 dried shiitake (15 grams) are (2):

• Calories: 44
• Carbs: 11 grams
• Fiber: 2 grams
• Protein: 1 gram
• Riboflavin: 11% of the Daily Value (DV)
• Niacin: 11% of the DV
• Copper: 39% of the DV
• Vitamin B5: 33% of the DV
• Selenium: 10% of the DV
• Manganese: 9% of the DV
• Zinc: 8% of the DV
• Vitamin B6: 7% of the DV
• Folate: 6% of the DV
• Vitamin D: 6% of the DV

In addition, shiitake contain many of the same amino acids as meat (3).

They also boast polysaccharides, terpenoids, sterols, and lipids, some of which have immune-boosting, cholesterol-lowering, and anticancer effects (4).

The amount of bioactive compounds in shiitake depends on how and where the mushrooms are grown, stored, and prepared (3).

Summary

Shiitake mushrooms are low in calories. They also offer many vitamins, minerals, and other health-promoting compounds.

How Are They Used?

Shiitake mushrooms have two main uses — as food and as supplements.

Shiitake as Whole Foods

You can cook with both fresh and dried shiitake, although the dried ones are slightly more popular.

Dried shiitake have an umami flavor that's even more intense than when fresh.

Umami flavor can be described as savory or meaty. It's often considered the fifth taste, alongside sweet, sour, bitter, and salty.

Both dried and fresh shiitake mushrooms are used in stir-fries, soups, stews, and other dishes.

Shiitake as Supplements

Shiitake mushrooms have long been used in traditional Chinese medicine. They're also part of the medical traditions of Japan, Korea, and Eastern Russia (4).

In Chinese medicine, shiitake are thought to boost health and longevity, as well as improve circulation.

Studies suggest that some of the bioactive compounds in shiitake may protect against cancerand inflammation (4).

However, many of the studies have been done in animals or test tubes rather than people. Animal studies frequently use doses that far exceed those that people would normally get from food or supplements.

In addition, many of the mushroom-based supplements on the market have not been tested for potency (5).

Although the proposed benefits are promising, more research is needed.

Summary

Shiitake have a long history of use, both as a food and in supplements.

May Aid Heart Health

Shiitake mushrooms may boost heart health. For example, they have three compounds that help lower cholesterol (3, 6Trusted Source, 7Trusted Source):

• Eritadenine. This compound inhibits an enzyme involved in producing cholesterol.

• Sterols. These molecules help block cholesterol absorption in your gut.

• Beta glucans. This type of fiber can lower cholesterol.

One study in rats with high blood pressure found that shiitake powder prevented an increase in blood pressure (8Trusted Source).

A study in lab rats fed a high-fat diet demonstrated that those given shiitake developed less fat in their livers, less plaque on their artery walls, and lower cholesterol levels than those that didn't eat any mushrooms (9Trusted Source).

Still, these effects need to be confirmed in human studies before any solid conclusions can be made.

Summary

Several compounds in shiitake help lower cholesterol and may reduce your risk of heart disease.

May Boost Your Immune System

Shiitake may also help strengthen your immune system.

One study gave people two dried shiitake daily. After one month, their immune markers improved and their inflammation levels dropped (10Trusted Source).

This immune effect might be partly due to one of the polysaccharides in shiitake mushrooms (11Trusted Source).

While people's immune systems tend to weaken with age, a mouse study found that a supplement derived from shiitake helped reverse some age-related decline in immune function (12Trusted Source).

Summary

Eating shiitake mushrooms regularly may help boost your immune system.

Contain Compounds With Potential Anticancer Activity

Polysaccharides in shiitake mushrooms may also have an anticancer effect (13Trusted Source, 14Trusted Source).

For example, the polysaccharide lentinan helps fight tumors by activating your immune system (15, 16Trusted Source).

Lentinan has been shown to inhibit the growth and spread of leukemia cells (17Trusted Source).

In China and Japan, an injectable form of lentinan is used alongside chemotherapy and other major cancer treatments to improve immune function and quality of life in people with gastric cancer (18Trusted Source, 19Trusted Source).

However, evidence is insufficient to determine whether eating shiitake mushrooms has any effect on cancer.

Summary

Lentinan is a polysaccharide in shiitake mushrooms that may help fight cancer.

Other Potential Benefits

Shiitake mushrooms may also help fight infections and promote bone health.

Promising Antibacterial and Antiviral Effects

Several compounds in shiitake have antibacterial, antiviral, and antifungal effects (18Trusted Source, 20).

As antibiotic resistance is growing, some scientists think it's important to explore the antimicrobial potential of shiitake (21Trusted Source).

That said, while isolated compounds show antimicrobial activity in test tubes, eating shiitake is unlikely to have any effect on viral, bacterial, or fungal infections in people.

May Strengthen Your Bones

Mushrooms are the only natural plant source of vitamin D.

Your body needs vitamin D to build strong bones, yet very few foods contain this important nutrient.

The vitamin D levels of mushrooms vary depending on how they're grown. When exposed to UV light, they develop higher levels of this compound.

In one study, mice fed a low-calcium, low-vitamin-D diet developed symptoms of osteoporosis. In comparison, those given calcium and UV-enhanced shiitake had higher bone density (22Trusted Source).

However, keep in mind that shiitake provide vitamin D2. This is an inferior form compared with vitamin D3, which is found in fatty fish and some other animal foods.

Summary

Compounds in shiitake have antimicrobial properties, though you're unlikely to gain benefits from eating the mushrooms themselves. Shiitake with higher vitamin D levels may improve your bone density.

Possible Side Effects

Most people can safely consume shiitake, although some side effects may occur.

In rare cases, people can develop a skin rash from eating or handling raw shiitake (23Trusted Source).

This condition, called shiitake dermatitis, is thought to be caused by lentinan (24Trusted Source).

In addition, using powdered mushroom extract over a long period may cause other side effects, including stomach upset and sensitivity to sunlight (25Trusted Source, 26Trusted Source).

Some also claim that mushrooms' high purine levels can cause symptoms in people with gout. Nonetheless, research suggests that eating mushrooms is linked to a lower risk of gout (27Trusted Source).

Summary

Shiitake may cause some side effects, such as skin rashes. Shiitake extract may also cause digestive problems and increased sensitivity to sunlight.

How to Cook With Shiitake

Mushrooms have a distinct umami flavor, which can be especially helpful when making vegetarian dishes.

Shiitake mushrooms are often sold dried. Before cooking, soak them in hot water to soften them.

To select the best specimens, look for ones sold whole rather than sliced. The caps should be thick with deep, white gills.

When cooking with fresh shiitake mushrooms, remove the stems, which remain tough even after cooking. Save the stems in the freezer for making veggie stock.

You can cook shiitake as you would any other mushroom. Here are a few suggestions:

• Sauté shiitake with greens and serve with a poached egg.

• Add them to pasta dishes or stir-fries.

• Use them to make a flavorful soup.

• Roast them for a crispy snack or side dish.

Summary

You can cook with either rehydrated, dried, or fresh shiitake mushrooms. They add a delicious, savory flavor to foods.

The Bottom Line

Shiitake have a long history of use, both as a food and a supplement.

While the research on the health benefits of these mushrooms is promising, very few human studies exist.

However, shiitake are low in calories and contain many vitamins, minerals, and bioactive plant compounds.

Overall, they're an excellent addition to your diet.