Shiitake

Studies in people

• Open question

  Cholesterol and blood fats³

  Eating shiitake bars cut triglycerides about 10% in people with borderline high cholesterol, though some sensitive people got a skin rash.

Animal and lab studies only

• Benefit

  Gut inflammation and bowel disease⁷

  In lab and animal studies, shiitake compounds reduced gut inflammation, but human evidence is limited.

• Benefit

  Tooth decay prevention⁸

  In lab studies, shiitake mushrooms may help prevent tooth decay, but more research is needed.

• No harm found

  Pregnancy and fetal development⁹

  In animal studies, pregnant rats fed shiitake showed no changes in their babies' body measurements.

• Benefit

  Blood sugar after eating¹⁰

  In lab studies, noodles with shiitake stem powder released less sugar during digestion than plain noodles.

Study type not stated

• Open question

  Gut bacteria and cholesterol⁵

  Shiitake may feed gut bacteria that make butyrate, and compounds in it are linked to cholesterol, but human proof is still thin.

Found in some samples or products

These come from where it was grown, how it was processed or cooked, or what it was made into. They are not about the ingredient itself, so the signal does not count them.

• Arsenic and cadmium levels⁶

  Shiitake mushrooms grown in Poland contained arsenic and cadmium at levels that may be bad for people who eat them.

Single cases of misuse or overdose

One person or one incident, such as an accidental overdose or a mistake in a kitchen or factory. They are real, but a single case does not show what happens at normal amounts, so the signal does not count them.

• Skin rash after eating²

  A woman got an itchy, streak-like rash on her trunk 48 hours after eating shiitake mushrooms.

• Skin rash from food⁴

  Eating raw shiitake mushrooms can cause an itchy, whip-like rash on the body.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.