Home Ingredients Shiitake Mushroom (Lentinula edodes)
Immune SupportCardiovascular

Shiitake Mushroom (Lentinula edodes)

Lentinula edodes
Evidence Level
Strong
2 Clinical Trials
5 Documented Benefits
4/5 Evidence Score

Shiitake is one of the most widely consumed culinary mushrooms globally — also extensively studied medicinally for its lentinan beta-glucan polysaccharide. Lentinan is approved as adjunct chemotherapy in Japan for stomach cancer (since 1985) — among the few mushroom compounds with prescription drug status. Used for immune support, cardiovascular health, and antioxidant effects. AHCC (an extract category) overlaps with shiitake research.

Studied Dose 1,000-3,000 mg/day mushroom extract; lentinan is typically given INJECTABLY (1-2 mg/week IV/IM) for oncology; oral lentinan absorption limited
Active Compound Lentinan (1,3-beta-glucan), eritadenine, ergosterol (vitamin D2 precursor), polyphenols

Benefits

Lentinan as Cancer Adjunct (Japan)

Lentinan has been approved prescription drug in Japan since 1985 as adjunct to chemotherapy for stomach cancer — given by injection. Multiple Japanese trials support extending survival in advanced gastric cancer. One of the most clinically-validated mushroom-derived compounds. Note: oral lentinan has limited absorption; injectable form drives evidence.

Supported by Trial 1

Cholesterol-Lowering (Eritadenine)

Shiitake contains eritadenine — a unique compound that lowers cholesterol via interference with phospholipid metabolism (specifically S-adenosyl methionine cycle). Animal studies show ~25% LDL reduction. Human evidence more modest.

Supported by Trial 1, Trial 2

Immune Modulation

Beta-glucans activate innate immunity — NK cells, macrophages, dendritic cells. Modest evidence for reduced respiratory infection severity.

Supported by Trial 2

Antioxidant Activity

Polyphenols, ergothioneine (sulfur amino acid antioxidant), and other compounds contribute to antioxidant capacity. Ergothioneine particularly notable as essentially mushroom-exclusive antioxidant.

Vitamin D Source (UV-Exposed)

Shiitake (and other mushrooms) contain ergosterol that converts to ergocalciferol (vitamin D2) when exposed to UV light. UV-treated shiitake (commercially available) provides meaningful vitamin D2 — among few non-animal vitamin D sources.

Supported by Trial 2

Mechanism of action

1

Lentinan Immune Activation

Lentinan is a 1,3-beta-glucan that activates dectin-1 and complement receptor pathways on immune cells. Activates Th1 cellular immunity and NK cell function. Mechanism well-characterized — basis for cancer adjunct evidence.

2

Eritadenine Cholesterol Mechanism

Eritadenine (2(R),3(R)-dihydroxy-4-(9-adenyl)-butyric acid) interferes with hepatic phospholipid biosynthesis — alters lipoprotein metabolism. Unique mechanism distinct from statins or other cholesterol drugs.

3

Ergothioneine Antioxidant

Ergothioneine is a sulfur-containing amino acid found almost exclusively in mushrooms (and bacteria/fungi). Acts as cellular antioxidant; concentrated in tissues with high oxidative stress (kidney, liver, RBCs).

4

UV Conversion to Vitamin D2

Ergosterol in mushrooms converts to ergocalciferol (D2) when exposed to UV light. UV-exposed shiitake can provide significant D2 (manufacturers sun-dry or UV-treat for this purpose).

Clinical trials

1
Lentinan for Gastric Cancer — Japanese Trials
PubMed

Multiple Japanese RCTs and post-marketing studies of injectable lentinan (1-2 mg IV/week) as adjunct to chemotherapy in advanced gastric cancer.

Advanced gastric cancer patients.

Improved survival when added to chemotherapy. Approved by Japanese authorities as prescription adjunct cancer drug since 1985. Critical: injectable formulation; oral lentinan has limited absorption.

2
Shiitake Whole Food Immune Effects — Dai 2015
PubMed

Trial of whole shiitake mushroom consumption (5-10 g/day) for 4 weeks in healthy adults. Outcomes: immune cell function, inflammation markers.

Healthy adults.

Improved gamma delta T-cell and NK cell function, reduced inflammatory markers. Supports general immune-supportive role of dietary shiitake.

Side effects and drug interactions

Common Potential side effects

Shiitake dermatitis — characteristic 'whiplash' linear streaks rash from raw or undercooked shiitake; well-documented; resolves spontaneously; cook shiitake thoroughly before consumption.
GI distress (especially raw mushroom).
Allergic reactions to mushroom.
Bleeding risk — modest at high doses.
Lentinan injection: fever, chills, GI distress (well-documented; manageable).

Important Drug interactions

Anticoagulants — theoretical bleeding risk at high doses.
Immunosuppressants — beta-glucan immune activation could theoretically interfere; avoid in transplant patients.
Chemotherapy — adjunctive use in Japan; consult oncologist.
Hypotensives — modest additive effects.

More Immune Support Ingredients

Immune Support
Vitamin C
Vitamin C (L-ascorbic acid) is a water-soluble essential nutrient that humans cannot synth…
Immune Support
Zinc
Zinc, an essential trace mineral, is commonly supplemented in forms like zinc gluconate, a…
Immune Support
Vitamin A
Vitamin A is a fat-soluble nutrient essential for vision, immune defense, reproduction, an…
Immune Support
EpiCor® (Postbiotic Yeast Fermentate — Cargill)
EpiCor® is a postbiotic ingredient from Cargill — derived from the fermentation of Sacchar…

Explore Other Ingredients

Immune Support
Turkey Tail Mushroom
Turkey tail (Trametes versicolor) is a medicinal mushroom studied mainly for immune suppor…
Immune Support
Reishi Mushroom
Reishi (Ganoderma lucidum) is a revered medicinal mushroom traditionally called the mushro…
Immune Support
Probiotics (Multi-strain Blends)
Multi-strain probiotic blends are the most common form of probiotic supplements — typicall…

Frequently asked questions about Shiitake Mushroom (Lentinula edodes)

What is shiitake mushroom used for?

Shiitake is a culinary and medicinal mushroom studied for immune support, healthy cholesterol, and antioxidant activity. Its beta-glucans (including lentinan) are the main immune-active compounds, and it is also a flavorful food.

What is lentinan in shiitake?

Lentinan is a beta-glucan from shiitake studied (in medical settings, often by injection) as an immune-support adjunct. Oral shiitake supplements and the whole mushroom provide beta-glucans for general immune support.

How much shiitake should I take?

Supplement doses vary by extract; follow product labeling. Eating shiitake as food is also beneficial. Look for extracts standardized to beta-glucans rather than just total polysaccharides.

Is shiitake safe?

Shiitake is safe as a food and generally well tolerated as a supplement. Raw or undercooked shiitake can rarely cause a temporary skin rash (shiitake dermatitis), so cook it well. Those on immune medications should check with a doctor.

What is Shiitake Mushroom?

Shiitake is one of the most widely consumed culinary mushrooms globally — also extensively studied medicinally for its lentinan beta-glucan polysaccharide. Lentinan is approved as adjunct chemotherapy in Japan for stomach cancer (since 1985) — among the few mushroom compounds with prescription drug status.

What is the recommended dosage of Shiitake Mushroom?

The clinically studied dose is 1,000-3,000 mg/day mushroom extract; lentinan is typically given Injectably (1-2 mg/week IV/IM) for oncology; oral lentinan absorption limited Always follow the product label and check with a healthcare provider for personal advice.

Is Shiitake Mushroom safe, and does it have side effects?

For most healthy adults, Shiitake Mushroom is well tolerated at studied doses. Reported effects can include: Shiitake dermatitis — characteristic 'whiplash' linear streaks rash from raw or undercooked shiitake; well-documented; resolves spontaneously; cook shiitake thoroughly before consumption. GI distress (especially raw mushroom). It may also interact with some medications. Shiitake Mushroom is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Shiitake Mushroom interact with any medications?

Possible interactions include: Anticoagulants — theoretical bleeding risk at high doses. Immunosuppressants — beta-glucan immune activation could theoretically interfere; avoid in transplant patients. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Shiitake Mushroom?

NutraSmarts rates the evidence for Shiitake Mushroom as Strong (4 out of 5). It is backed by 2 clinical trials and 4 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(4 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Oba K, Kobayashi M, Matsui T, Kodera Y, Sakamoto J Individual patient based meta-analysis of lentinan for unresectable/recurrent gastric cancer Anticancer Research. 2009;29(7):2739-45..PubMedUsed to support: Individual-patient-data meta-analysis indicating that injectable lentinan (a shiitake beta-glucan) added to chemotherapy prolonged survival in advanced gastric cancer; supports the injectable-lentinan cancer-adjuvant use, which is the stronger evidence base (distinct from oral shiitake).
  2. Dai X, Stanilka JM, Rowe CA, Esteves EA, Nieves C Jr, Spaiser SJ, et al. Consuming Lentinula edodes (Shiitake) Mushrooms Daily Improves Human Immunity: A Randomized Dietary Intervention in Healthy Young Adults Journal of the American College of Nutrition. 2015;34(6):478-87. doi: 10.1080/07315724.2014.950391.PubMedUsed to support: Small RCT in healthy young adults: daily oral shiitake improved several immune markers (e.g., gamma-delta T cell and NK activity, reduced inflammatory markers); supports a modest oral immune benefit, but the oral human evidence is limited and based on small, short studies.
  3. Zhao C, Yan H, Pang W, Wu T, Kong X, Li X, et al. Lentinan combined with cisplatin for the treatment of non-small cell lung cancer Medicine (Baltimore). 2021;100(12):e25220. doi: 10.1097/MD.0000000000025220.PubMedUsed to support: Clinical study in non-small cell lung cancer reporting that adding injectable lentinan to chemotherapy improved response and quality-of-life measures; further supports lentinan as a chemotherapy adjuvant (injectable, hospital setting), again distinct from and stronger than oral shiitake.
  4. Gil-Ramirez A, Caz V, Smiderle FR, Martin-Hernandez R, Largo C, Tabernero M, et al. Water-Soluble Compounds from Lentinula edodes Influencing the HMG-CoA Reductase Activity and the Expression of Genes Involved in the Cholesterol Metabolism Journal of Agricultural and Food Chemistry. 2016;64(9):1910-20. doi: 10.1021/acs.jafc.5b05571.PubMedUsed to support: Mechanistic study showing shiitake (Lentinula edodes) water-soluble compounds (eritadenine-type/beta-glucans) inhibit HMG-CoA reductase and modulate cholesterol-metabolism genes; provides a plausible cholesterol-lowering mechanism but is laboratory/mechanistic, so the human cholesterol benefit remains preliminary.