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Shiitake (Lentinula edodes, LEM)

Japanese culinary and medicinal mushroom, Lentinan polysaccharide is approved in Japan as an oncology adjuvant; consumer-supplement evidence is preliminary.

Why

Shiitake (Lentinula edodes) is one of the most-consumed culinary mushrooms globally. The polysaccharide Lentinan, isolated from shiitake, is approved in Japan as an injectable oncology adjuvant for gastric cancer. Oral consumer-supplement evidence (Lentinula edodes mycelium, LEM) is more preliminary, with small trials in lipid modulation, immune markers, and oral health. Distinct from the IV Lentinan use.

How it works

β-1,3-glucan polysaccharide (lentinan) activates innate immune cells via Dectin-1 and complement pathways, basis of the Japanese oncology approval. Eritadenine modestly lowers serum cholesterol via methionine metabolism modulation.

Expected onset · Immune markers within weeks; lipid effects over 4–8 weeks

How to take

Dosage

Whole mushroom: ~5–10 g dried daily. LEM extract: 1–3 g/day.

Timing

Once daily

On the label

Dual-extract whole shiitake fruiting body or LEM (Lentinula edodes mycelium). Avoid mycelium-on-grain products.

Ideal for

Adults including shiitake in their diet; those exploring polysaccharide-mushroom options for immune or lipid support. Oncology-adjuvant use of Lentinan is clinical-context only.

Safety

Shiitake dermatitis from raw or undercooked shiitake (flagellate erythematous eruption from lentinan), cook thoroughly. Allergic reactions to spores possible. Theoretical antiplatelet effect at higher doses. Pregnancy: culinary doses safe.

Evidence

At a glance

Dai 2015 RCT in young adults: daily shiitake consumption increased γδT and NK cell number/activity and reduced CRP at 4 weeks. Preliminary, RCTs exist in non-tier-1 journals but are small or short-duration. No Cochrane review, EMA monograph or EFSA-authorised claim covers the indication. Lentinan IV is approved in Japan for gastric cancer adjuvant use, distinct clinical context.

Limitations

Preliminary, RCTs exist in non-tier-1 journals but are small or short-duration. No Cochrane review, EMA monograph or EFSA-authorised claim covers the indication.

Where to get it

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