Organic Shiitake mushroom extract
Also known as: Shiitake mushroom, black forest mushroom, Shiitake mushroom extract, Lentinula edodes
Overview
Shiitake mushroom extract is derived from the fruiting bodies of Lentinula edodes, a fungus native to East Asia, traditionally consumed as food and used in traditional medicine. It is rich in bioactive compounds, notably β-glucans (polysaccharides), lentinan (a specific β-glucan), and eritadenine. Primarily used for its purported immunomodulatory, anticancer, and gut health benefits, research includes in vitro, animal, and human clinical studies, with some systematic reviews available. While preclinical data are robust, clinical trial results show mixed outcomes, particularly concerning its use as an adjunct in cancer therapy. The extract is generally considered safe with a low incidence of adverse effects.
Benefits
Shiitake mushroom extract offers several evidence-based benefits. For immune support, clinical trials show that consuming 5-10 g/day of shiitake mushroom powder for 14 days can enhance immune parameters, including increased activation of γδ-T cells and NK cells, increased salivary secretory IgA, and reduced C-reactive protein (CRP), indicating improved immune function and reduced inflammation in healthy adults. Regarding anticancer potential, a 2021 systematic review and meta-analysis of observational studies found a significant association between higher mushroom consumption, including shiitake, and a lower risk of certain cancers. Lentinan, a purified β-glucan from shiitake, has been studied as an adjunct to chemotherapy in gastric cancer; a 2002 meta-analysis showed a modest improvement in overall survival, though a 2016 phase 3 RCT found no significant survival benefit. For gut health, β-glucans in shiitake support the gut microbiota by promoting the production of short-chain fatty acids like butyrate, which has anti-inflammatory effects and contributes to digestive health. Some less quantified evidence also suggests improvements in mental state, physical energy, and recovery quality during illness.
How it works
The primary bioactive components in shiitake mushroom extract are β-glucans, which act as immunomodulators. They bind to pattern recognition receptors, such as Dectin-1, on immune cells, thereby enhancing both innate and adaptive immune responses. Specifically, lentinan stimulates macrophages, natural killer (NK) cells, and T lymphocytes, promoting the production of cytokines like IL-4, IL-10, and TNF-α, which enhances immune surveillance against tumors. Additionally, β-glucans modulate the gut microbiota composition, increasing beneficial bacteria and the production of short-chain fatty acids. This contributes to overall gut health and systemic immune function. The bioavailability of these compounds can vary depending on the extraction method and molecular weight; while purified lentinan is sometimes administered intravenously in cancer trials, oral consumption of powder or extract is common for general immune support, with effects likely mediated via gut-associated lymphoid tissue.
Side effects
Shiitake mushroom extract is generally considered safe with a low incidence of adverse effects. Common side effects, occurring in less than 5% of users, are rare and may include mild gastrointestinal discomfort or allergic reactions in sensitive individuals. A rare but notable adverse effect, occurring in less than 1% of cases, is shiitake dermatitis, characterized by a distinctive flagellate (whip-like) rash that appears after consuming raw or undercooked shiitake mushrooms. While no major drug interactions have been definitively documented, caution is advised when combining shiitake with immunosuppressants or anticoagulants due to theoretical concerns regarding immune stimulation or potential blood-thinning effects. Contraindications include a known allergy to mushrooms or other fungal products. For special populations such as pregnant or breastfeeding women, there is insufficient data to make definitive safety conclusions, and use should be approached with caution or avoided.
Dosage
For immune function improvements, a minimum effective dose of 5 g of dried shiitake mushroom powder daily has been observed in clinical studies. The optimal dose range commonly used in trials is 5-10 g/day of dried mushroom powder or an equivalent extract standardized for β-glucans (typically ≥30-50%). In specific cancer trials, purified lentinan has been administered intravenously at varying doses, such as 2.5 mg/day. There is no established maximum safe dose; however, doses up to 10 g/day of dried mushroom powder have been well tolerated in short-term studies. Shiitake is typically administered daily, with immune benefits observed after approximately 14 days of consistent supplementation. The extract is available in various forms, including powder, capsules, or purified β-glucan extracts, and their bioavailability and efficacy may differ. Oral bioavailability of β-glucans is limited, with immune effects likely mediated via interaction with gut-associated lymphoid tissue.
FAQs
Is shiitake extract effective for cancer?
Evidence is mixed; some meta-analyses suggest a modest benefit as an adjunct therapy in gastric cancer, but high-quality randomized controlled trials show inconsistent results.
Can shiitake boost immunity in healthy people?
Yes, moderate-quality randomized controlled trials indicate improved immune markers after 5-10 g/day intake for 2 weeks in healthy adults.
Are there safety concerns?
Generally safe; avoid raw shiitake to prevent dermatitis. Allergic reactions are possible but rare. Consult a healthcare professional if you have concerns.
How soon do effects appear?
Immune improvements have been observed within 2 weeks of daily intake of shiitake mushroom extract.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8483951/ – This systematic review and meta-analysis of observational studies found a significant association between higher mushroom consumption, including shiitake, and a lower risk of certain cancers. The study highlights the potential chemopreventive effects of mushrooms based on pooled data from numerous studies, though its observational design limits conclusions on causality.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8401741/ – This review of randomized controlled trials and clinical studies indicates that shiitake intake (5-10 g/day) can improve immune cell activation, increase salivary IgA, and reduce C-reactive protein in healthy adults. The findings suggest a beneficial immunomodulatory effect, although some included trials had small sample sizes and heterogeneity in doses.
- https://www.cancertherapyadvisor.com/factsheets/shiitake-mushroom-lentinan-and-cancer/ – This summary reviews meta-analyses and randomized controlled trials on lentinan as an adjunct to chemotherapy for gastric cancer. It notes that while a meta-analysis showed modest improvement in overall survival, a more recent phase 3 RCT did not demonstrate significant survival benefits, indicating mixed and inconsistent results for its use in cancer treatment.