Nutritional benefits of Mushrooms

Firstly, no specific food is a “cure” for cancer, so try not to read too much into these studies. That said, shiitake mushrooms contain various compounds that research demonstrates as having anti-cancer effects. Among these compounds is lentinan, a type of beta-glucan polysaccharide that displays anti-tumor activity. Notably, research on this compound has shown that high-dose extracts can “significantly decrease” the proliferation (spread) of specific types of cancer cells.
These anti-tumor compounds have also displayed beneficial effects in animal studies.

Shiitake mushrooms provide a substantial amount of the essential mineral copper. Per 100 grams, dried mushrooms contain 258% of the RDA for this essential mineral. For 100 grams of fresh, cooked mushrooms, the provision is 45% of the RDA. This separates shiitake from oyster mushrooms in that they have almost 4 times the amount of copper than that of oyster mushrooms. Copper plays a role in various biological functions, and it is known to be essential for developing and maintaining a healthy immune system. Furthermore, copper deficiency has strong links to cardiovascular disease in animal studies. However, more research is necessary to determine if this is also true for humans.

To increase the vitamin D2 and D4 levels in your mushrooms, simply slice the caps in half, and leave gill side up in sunlight for 12 to 24 . This has a drastic effect in raising the levels of Vitamin D2 and D4 in mushrooms. Oyster mushrooms have the potential to contain twice the amount of Vitamin D2 and D4 as Shiitake after the already mentioned technique.

Information about Vitamin D and it's relation to mushrooms can be found in the following link.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213178/ 

Unfortunately, it is not possible to confidently estimate how much vitamin D is in each mushroom, as this can significantly vary depending on the level of sun exposure (if any). However, vitamin D concentrations can sometimes be extremely high. For instance, dried shiitake mushrooms grown with full sun exposure may offer amounts as high as 46,000 IU per 100 grams. 

A variety of research shows that shiitake mushrooms and oyster mushrooms contain compounds that have anti-inflammatory properties. Researchers believe these anti-inflammatory effects are due to compounds such as ergothioneine and polysaccharides. However, having anti-inflammatory properties and being proven at reducing inflammation in humans are two distinctly separate things. While some studies (in vivo and in vitro) show evidence that  mushrooms modestly decrease inflammation in human subjects, further evidence is needed.

Mushrooms contain vitamin D2, as well as lesser amounts of vitamin D3 and D4. Vitamin D2 and D3 are the two most important forms for your health. Vitamin D2 is produced by plants, and Vitamin D3 is the one made by your skin when you get enough sunlight. Fortified foods can contain either form. Studies show that Vitamin D3 is far more important for our health than Vitamin D2.   Plants produce Vitamin D2 when they are exposed to UV light (in much the same way as our bodies naturally produce Vitamin D). The most common example is wild mushrooms or mushrooms produced under UV light. Dairy-free milk (including soya, coconut, and almond milk) are often boosted with D2. It is very important for vegetarians and vegans to get enough sunlight as well as vitamin D2 as you are not getting vitamin D3 from animal products.