Dried Shiitake Mushrooms

There are two main varieties of shiitake mushrooms. The thicker "donko" variety, and the "koshin" variety which is more suitable to use in dashi.

Dried shiitake mushrooms are characterized by their high dietary fiber content. They also contain biotin, which is known to maintain skin and mucous membranes, as well as healthy nails and hair.
The ergosterol contained in shiitake mushrooms is converted into vitamin D. As a result, they are rich in vitamin D, which helps with calcium absorption, so it is good to eat shiitake with foods that are rich in calcium. Vitamin D is abundant in animal foods, and is a nutrient that tends to be lacking in people who follow a plant-based diet, so dried shiitake mushrooms are a good supplementary food for vegetarians and vegans. 
Drying them in the sun increases vitamin D as well as lenthionine, which is expected to have the effect of preventing lifestyle-related diseases such as arteriosclerosis. In addition, glutamic acid, the umami component contained in shiitake mushrooms, is known to have various effects, such as maintaining the health of the brain and intestines and producing GABA.

Store unopened packages of dried shiitake mushrooms in a cool, dark place with low humidity. Once opened, avoid excess moisture absorption.