Shiitake mushrooms: benefits for immunity and health

The shiitake mushroom (Lentinula edodes) is one of the most widely eaten mushrooms in Asia. It is now making its way into European health cuisine thanks to its rich nutritional content. It has long been used in traditional medicine, and modern research now confirms its benefits for immunity, metabolism and vitality.

What are shiitake mushrooms?

Shiitake is a wood-grown Asian mushroom with a brown cap. Its distinctive umami flavour sets it apart from other edible species. It is a natural source of fibre, minerals, antioxidants and beta-glucans. These compounds largely explain its status as a ‘health food’. When exposed to UV light, it also provides vitamin D2, useful for immunity and bone strength.

Shiitake and immunity : what studies show

The shiitake mushroom benefits from a large body of scientific evidence. A clinical study involving 52 adults evaluated consumption of 5 to 10 g of dried shiitake per day for 4 weeks. The participants showed a more marked activation of key immune cells (γδ-T, NK-T), an increase in salivary IgA and a drop in CRP, a marker of inflammation.

These data indicate that shiitake may boost natural defences and reduce inflammation, particularly in the digestive tract. Other studies also show an action on the intestinal microbiota, probably thanks to its fibres and polysaccharides.

Other benefits of shiitake mushrooms

Shiitake mushrooms have other benefits:

• Metabolic balance: several studies have observed a moderate drop in total cholesterol and an improvement in certain cardio-metabolic parameters with regular consumption.
• Liver protection: preclinical studies and a few human trials suggest a protective effect, especially when consumed as part of an overall healthy lifestyle.

In integrative oncology, extracts derived from shiitake mycelium (such as AHCC) are sometimes used with treatments to support immunity and improve tolerance. However, such use requires strict supervision by specialist medical teams.

How should shiitake mushrooms be eaten?

The simplest way is to include it in your diet. It can be cooked two or three times a week in frying pans, woks or soups. It should always be cooked thoroughly. Clinical studies evaluating its immune effect generally use 5 to 10 g of dried shiitake a day for a few weeks.

As a dietary supplement, shiitake comes in powder, capsule or polysaccharide-standardised extract form, often combined with other medicinal mushrooms. Dosages vary depending on the objective: immune support, vitality or metabolic balance. The advice of a health professional is therefore essential in choosing the most suitable form.

Side effects and precautions with shiitake

Healthy adults generally tolerate well-cooked shiitake as part of their diet. On the other hand, raw or undercooked shiitake can cause flagellate dermatitis, a very itchy, streaky rash described in several clinical cases.

Some people may also experience digestive problems (nausea, diarrhoea) or allergic reactions , especially with high doses of supplements. Concentrated extracts are not recommended for pregnant or breast-feeding women without medical advice. These extracts are not recommended for transplant patients, those undergoing immunosuppressive treatment or those who have already reacted to mushrooms.