As Western countries start expanding their taste buds to include mushrooms, shiitake mushrooms have been one of the most commercially valuable species. However, shiitake mushrooms have been cultivated for hundreds of years – if not thousands – in places like Japan. 

 

So, what’s the deal with these shiitake mushrooms? 

Shitake Mushrooms

 

Keep reading to learn everything you need to know about shiitake mushrooms – from the health benefits to cooking methods!

What is a Shiitake Mushroom?

Like all mushrooms, a shiitake mushroom is the reproductive body of Lentinula edodes. This fungus prefers a wood-based substrate and can be grown on a number of different tree species. Shiitake mushrooms have a rich umami (meaty, savory) flavor – making them one of the most prized culinary mushrooms.

 

Home growers can easily grow this strain on old stumps using the plug method. This consists of drilling a hole in a stump, pounding in a wooden dowel covered in fungi mycelium, then sealing the opening with wax. Commercially, this mushroom is typically grown on sterilized wood chips and sawdust.

Shiitake Mushrooms and Health

Besides being a culinary delight, shiitake mushrooms have been through decades of research that show many benefits to human health. The most important components of shiitake mushrooms seem to be the vitamin D and fiber they contain.

 

Vitamin D is a very important nutrient for both the immune system and the strength of bones. Vitamin D helps regulate the activity of your immune system, ensuring that your immune system reacts properly to invasive viruses and bacteria. Vitamin D also helps regulate calcium levels in your blood, which in turn helps ensure that your bones stay strong and healthy.

 

What are the specific benefits of shiitake mushrooms?

Bone Health

Studies in rats have shown that vitamin D obtained from shiitake mushrooms successfully increased bone density. While this effect still needs further study in humans, the results suggest that eating shiitake mushrooms a few times a week could significantly improve the strength of your bones and reduce your risk of fractures. This effect is likely related to the vitamin D present in sun-exposed shiitake mushrooms.

 

Immune System

The vitamin D present in shiitake mushrooms also seems to positively impact the immune system. A comprehensive study on the effects of daily shiitake mushroom intake in humans revealed that shiitake mushrooms seem to have several benefits for the immune system. Overall immune cell activity is increased – this is a good thing because these cells catch and destroy pathogens. 

 

Plus, the increases in immune cell function did not come with increased inflammation. Inflammation can cause some of the most severe symptoms when infected with a virus or bacteria, so decreased inflammation is a good thing.

 

Anti-Viral Activity

A study in mice showed that the vitamin D supplement provided from shiitake mushrooms was able to help heal severely damaged livers recover from hepatitis-C infection. While further human studies are required, this study showed that damage caused by hepatitis-C could be treated with shiitake mushroom extracts. The authors hypothesize that this effect may be due to the immune system effects of vitamin D, but the fiber and nutrients of the mushrooms may have also contributed to the healing effects seen in the liver tissue.

Cancer

A review of the shiitake mushroom literature revealed that several anti-tumor properties are associated with shiitake mushrooms and shiitake extracts. The study also notes that in Japan, shiitake mushrooms are prescribed alongside chemotherapy and radiation for treating invasive cancers. While the exact mechanism is not well researched, the Japanese method does seem to provide a significant benefit to patients.

Can Shiitake Mushrooms Be Bad for You?

The only downside to shiitake mushrooms is that some people can be allergic to a specific chemical the mushrooms produce – lentinan. Few other side effects – if any – have been reported in the scientific literature. However, for those with a shiitake allergy the symptoms can be painful, uncomfortable, and potentially problematic

 

So, if you have never eaten shiitake mushrooms before you should definitely test a small piece before you dive face-first into a delicious plate-full. The rate of people who are allergic to shiitake mushrooms seems to be relatively low. 

Shiitake Supplements vs Whole Mushrooms

Researchers and clinicians have certainly suggested that whole shiitake mushrooms can be used to supplement your vitamin D intake. In fact, shiitake mushrooms have even been analyzed for their vitamin D content. Interestingly, there is a difference between fresh and sun-dried shiitake mushrooms.

 

Shiitake mushrooms, fresh  ∼100 IU/3.5 oz vitamin D2 
Shiitake mushrooms, sun-dried  ∼1,600 IU/3.5 oz vitamin D2 

 

Essentially, a normal adult can meet their nutritional requirement of vitamin D with 600 IU per day. In terms of how many mushrooms you have to eat, it’s not many! 600 International Units translates to about 1.3 ounces of dried mushrooms – approximately a small handful.

 

You should note that only UV exposed shiitake mushrooms – such as those placed in the sun – have significant amounts of vitamin D. It is still unclear if shiitake powder or supplements derived from shiitake mushrooms have the same beneficial effects. Some preliminary studies have indicated that shiitake powder may retain the important components that can aid in diabetes and other health conditions.