Heimuer

Metadata

Regulatory Status

Chinese Pharmacopoeia

• Listed: Yes. Heimuer (黑木耳) is an official drug in the Chinese Pharmacopoeia (2020 edition), listed under the Auricularia drug entry. Note: the pharmacopoeia uses the older name Auricularia auricula (now A. heimuer).
• Dual-use status: Officially recognized as both food and traditional Chinese medicine in China. This dual status is shared with relatively few fungal species and reflects the deep integration of Heimuer into both Chinese cuisine and medical practice.
• Traditional indications: Nourishing yin, moistening the lungs, nourishing the stomach, promoting blood circulation, stopping bleeding (hemostatic — paradoxically, despite blood-moving properties). Indicated for qi and blood deficiency, cough with lung dryness, hemoptysis, and deficiency-type bleeding.
• Official dose: 6-12 g dried fruiting body in decoction.

Classical Chinese Texts

• Heimuer has been documented in Chinese medicinal texts for over 1,500 years. It appears in the Shennong Bencao Jing (circa 200 CE) and subsequent materia medica compilations. Li Shizhen’s Bencao Gangmu (1596) provides detailed descriptions of its medicinal properties, preparation methods, and habitat.
• In TCM theory, Heimuer is classified as sweet in flavor, neutral in temperature, and entering the stomach, large intestine, and liver meridians. Its primary TCM functions are to nourish yin and moisten dryness, promote blood circulation, and stop bleeding.

Korean Traditional Medicine

• Recognition: Known as “Mok-yi” (목이) in Korean. Used in Korean traditional medicine (Hanbang) for blood circulation, cardiovascular support, and as a nutritious food medicine. Documented in Korean medicinal texts including the Dongui Bogam (1613).
• Dual use: Widely consumed as both food and medicine in Korean cuisine (commonly in soups, stir-fries, and salads).

Japan

• Food status: Widely consumed as “Kikurage” (キクラゲ, lit. “tree jellyfish”) in Japanese cuisine. Not listed in the Japanese Pharmacopoeia as a medicinal product, but recognized as a traditional health food.
• Dietary use: Common ingredient in ramen, miso soup, stir-fries, and salads. Imported primarily from China.

United States

• Dietary supplement: Marketed as a dietary supplement under DSHEA, typically as “Black Fungus Extract” or “Wood Ear Extract” in capsule or powder form.
• Food status: Widely available as a dried food ingredient in Asian grocery stores throughout the US. No GRAS determination for concentrated extracts, though the whole food has a long history of consumption.

European Union

• Novel food: Auricularia preparations have been consumed in some EU member states (particularly those with significant Asian populations) for decades, and dried wood ear mushrooms are available in food markets. Novel food status for concentrated extracts may vary.
• No EMA/HMPC monograph.

Conditions & Indications

Primary: Cardiovascular Health and Blood Circulation (TCM Tradition + Preclinical/Limited Clinical Evidence)

• Anticoagulant and antiplatelet activity: Heimuer has been used in TCM for centuries to “promote blood circulation” (huo xue). Modern research has confirmed adenosine-mediated antiplatelet activity: adenosine, present in significant concentrations in Heimuer, inhibits platelet aggregation through activation of A2A receptors on platelet surfaces. Polysaccharide fractions also demonstrate anticoagulant activity through inhibition of thrombin and enhancement of antithrombin III activity in vitro and in animal models. Hammerschmidt (1980) published a landmark case study reporting that prolonged consumption of a traditional Chinese diet rich in Heimuer was associated with reduced platelet aggregation in a patient.
• Lipid-lowering effects: Multiple animal studies and several small human trials have demonstrated that Heimuer polysaccharide supplementation reduces total cholesterol, LDL cholesterol, and triglycerides while increasing HDL cholesterol. The mechanism involves inhibition of hepatic HMG-CoA reductase activity (the same target as statin drugs), enhanced bile acid excretion, and modulation of cholesterol absorption in the intestine. Clinical evidence, while encouraging, comes from small trials with methodological limitations.
• Hemorheological improvement: Heimuer extracts improve blood rheological properties (reducing blood viscosity, enhancing red blood cell deformability, reducing erythrocyte aggregation) in both animal models and small human studies. These hemorheological effects support the traditional TCM indication of “promoting blood circulation” and are relevant to cardiovascular risk reduction, particularly in conditions associated with hyperviscosity.

Secondary: Antioxidant and Immunomodulatory Effects (Preclinical Evidence)

• Antioxidant activity: Polysaccharide and melanin fractions demonstrate significant free radical scavenging activity (DPPH, hydroxyl, superoxide) and metal chelation capacity. The melanin content of Heimuer is unusually high among edible mushrooms and contributes substantially to its antioxidant profile. Melanin also provides UV-protective and metal-chelation properties.
• Immunomodulation: Polysaccharide fractions activate macrophages, enhance NK cell activity, and stimulate cytokine production (TNF-alpha, IL-6, IFN-gamma) through Dectin-1 and TLR-2 receptor engagement, consistent with the broader medicinal mushroom polysaccharide immunomodulatory paradigm.
• Iron supplementation: Heimuer is one of the richest dietary sources of iron among mushrooms (typically 40-100 mg/100g dry weight), contributing to its traditional use for blood nourishment (bu xue) in TCM. The iron is primarily in non-heme form, with bioavailability enhanced by the concurrent presence of ascorbic acid.

Emerging/Preclinical

• Anti-obesity and metabolic effects: Animal studies demonstrate that Heimuer polysaccharides modulate gut microbiota composition, reduce body weight gain on high-fat diets, improve glucose tolerance, and reduce hepatic lipid accumulation. The prebiotic effects on gut microbiota (increasing Bacteroidetes relative to Firmicutes) parallel findings reported for reishi polysaccharides.
• Hepatoprotective effects: Polysaccharide fractions protect against chemically induced liver injury in animal models, reducing serum transaminases and hepatic oxidative stress markers.
• Anti-tumor activity: Polysaccharide fractions demonstrate anti-tumor activity in sarcoma 180 and H22 hepatoma mouse models, with tumor inhibition rates of 30-70%. The mechanism appears to be primarily immunomodulatory rather than directly cytotoxic. Lectin (AAL) from A. heimuer demonstrates selective agglutination of tumor cells.
• Radioprotective effects: Preclinical evidence suggests that Heimuer polysaccharides provide some protection against radiation-induced hematopoietic damage, relevant to the Chinese Pharmacopoeia indication for use in cancer patients receiving radiation therapy.

Mechanism of Action

Primary Mechanisms

1. Adenosine-mediated antiplatelet activity: Adenosine, present in nutritionally significant concentrations in Heimuer fruiting bodies, inhibits platelet aggregation through activation of A2A adenosine receptors on the platelet surface. A2A receptor activation stimulates adenylyl cyclase, increasing intracellular cAMP levels, which in turn inhibits platelet activation signaling cascades including glycoprotein IIb/IIIa conformational change (necessary for fibrinogen binding and platelet cross-linking). This mechanism is pharmacologically identical to the antiplatelet activity of endogenous adenosine in the vascular system and parallels the adenosine-mediated antiplatelet effects documented for Reishi (Ganoderma lucidum). The clinical consequence is reduced platelet aggregation and potentially reduced thrombotic risk with regular consumption.

2. Polysaccharide-mediated lipid metabolism modulation: Acidic heteropolysaccharides from Heimuer — characterized by high mannose and glucuronic acid content with beta-(1,3) and beta-(1,6) linkages — reduce blood lipid levels through multiple convergent mechanisms: (a) inhibition of hepatic HMG-CoA reductase, reducing endogenous cholesterol synthesis (the same enzymatic target as pharmaceutical statins); (b) enhanced fecal bile acid excretion, reducing the enterohepatic bile acid pool and forcing hepatic conversion of additional cholesterol to bile acids; (c) reduced intestinal cholesterol absorption through binding of dietary cholesterol and bile acids in the gut lumen. Animal studies demonstrate 20-40% reductions in total cholesterol and 15-30% reductions in LDL cholesterol at effective polysaccharide doses.

3. Hemorheological modulation: Heimuer extracts reduce whole blood viscosity and plasma viscosity through: (a) reduction of fibrinogen levels (a major determinant of plasma viscosity); (b) enhancement of red blood cell deformability (improving microcirculatory flow); (c) reduction of erythrocyte aggregation. These effects collectively improve blood flow properties and microcirculation, providing the pharmacological basis for the TCM indication of “promoting blood circulation” (huo xue).

Secondary Mechanisms

• Melanin antioxidant and metal chelation: Heimuer melanin — a heterogeneous polymer of phenolic and indolic subunits — provides broad-spectrum antioxidant activity through radical scavenging, singlet oxygen quenching, and transition metal chelation. The high melanin content of Heimuer is unusual among edible mushrooms and contributes to both antioxidant protection and the characteristic dark color of the fruiting body.
• Polysaccharide immunomodulation: Beta-glucan and heteropolysaccharide fractions activate innate immune cells through Dectin-1, TLR-2, and complement receptor 3 (CR3), enhancing macrophage phagocytosis, NK cell cytotoxicity, and dendritic cell maturation. This mechanism is shared with other medicinal mushroom polysaccharides but is secondary to the cardiovascular applications for Heimuer specifically.
• Dietary fiber effects: The high dietary fiber content (30-40% dry weight, including chitin, beta-glucans, and other polysaccharides) contributes to cholesterol reduction through bile acid binding in the gut, glycemic control through delayed carbohydrate absorption, and potential prebiotic effects on gut microbiota composition.
• Lectin (AAL) activity: Auricularia lectin demonstrates selective binding to specific carbohydrate structures on cell surfaces, with reported anti-tumor activity through selective agglutination of transformed cells. The clinical significance is unknown.

Key Active Compounds

Clinical Evidence Summary

Clinical evidence for Auricularia heimuer (published under the older name A. auricula or A. auricula-judae) is moderate in volume but limited in quality. Most clinical studies are small, open-label, and conducted in China, with some published only in Chinese-language journals.

Key Clinical and Human Studies

Preclinical Evidence (Selected)

Evidence Limitations

• Clinical trial quality: Most human studies are small (n=40-80), short-duration (4-12 weeks), and conducted at single centers in China. Few use double-blind, placebo-controlled designs. Randomization and allocation concealment methods are not always adequately described.
• Taxonomic confusion in literature: All clinical studies published before 2015 use the names A. auricula, A. auricula-judae, or A. polytricha rather than the correct name A. heimuer. While most Chinese studies almost certainly used A. heimuer (the commercially cultivated species in China), definitive confirmation is not possible without voucher specimen molecular verification.
• Extract standardization variability: Studies use different preparations (dried powder, hot-water extract, purified polysaccharide fraction) at different doses, complicating cross-study comparison and meta-analysis.
• Publication bias: The majority of clinical studies originate from Chinese institutions, and positive results may be overrepresented in the accessible literature. Negative or null results may be underreported.
• Confounding by dietary context: The Hammerschmidt (1980) case report and some dietary studies do not control for other dietary factors that may contribute to the observed cardiovascular effects. Heimuer is typically consumed as part of a broader Chinese dietary pattern rich in vegetables, soy, and other potentially cardioprotective foods.
• Long-term outcomes unknown: No studies have examined hard cardiovascular endpoints (cardiovascular events, mortality) with Heimuer supplementation. All evidence concerns surrogate markers (lipid levels, blood viscosity, platelet aggregation).

Safety Profile

General Assessment

Auricularia heimuer is one of the most widely consumed mushrooms in the world, with over 6 million tonnes produced annually and centuries of culinary use across East Asia. Its safety profile as a food is well-established through massive population-level exposure. TCM pharmacopoeia sources consider it a mild, well-tolerated medicine suitable for long-term use. However, its antiplatelet activity represents a clinically meaningful pharmacological effect that requires consideration in certain populations.

Contraindications

• Bleeding disorders or thrombocytopenia: Heimuer has demonstrated antiplatelet activity through adenosine-mediated A2A receptor activation. Avoid in patients with existing bleeding disorders or low platelet counts.
• Pre-surgical: Discontinue Heimuer consumption (particularly concentrated extracts) at least 1-2 weeks before scheduled surgery due to antiplatelet effects. Dietary quantities of cooked Heimuer likely pose minimal risk, but caution is warranted.
• Pregnancy: Traditional TCM sources classify Heimuer as a “blood-moving” (huo xue) medicine, which is traditionally cautioned during pregnancy due to theoretical risk of increasing uterine blood flow. Modern evidence is insufficient to confirm or refute this risk. Concentrated extracts should be avoided during pregnancy; dietary consumption of cooked Heimuer is likely safe at normal culinary quantities based on widespread traditional practice, but specific safety studies are lacking.

Drug Interactions

• Anticoagulants and antiplatelets (warfarin, heparin, aspirin, clopidogrel): Additive antiplatelet effect through adenosine-mediated platelet inhibition. May increase bleeding risk with concurrent use. The clinical significance depends on the amount consumed — dietary quantities likely pose lower risk than concentrated extracts. Severity: Moderate. Monitor for signs of bleeding.
• Antihypertensives: Theoretically additive hypotensive effect based on vasodilatory properties of adenosine. Clinical significance at dietary doses is likely minimal. Severity: Low.
• Antidiabetic agents: Based on preliminary clinical evidence suggesting glucose-lowering effects, additive hypoglycemia risk is possible with insulin or oral hypoglycemic agents when consuming concentrated polysaccharide extracts. Severity: Low-to-moderate with concentrated extracts.
• Lipid-lowering drugs (statins, fibrates): Theoretically additive effect on lipid reduction based on demonstrated HMG-CoA reductase inhibitory activity of polysaccharides. Clinical significance is uncertain. Severity: Low.

Side Effects

• Common: Generally well-tolerated as food. Gastrointestinal effects (bloating, flatulence) may occur due to high dietary fiber content, particularly when consumed in large quantities or by individuals not accustomed to high-fiber diets.
• Uncommon: Allergic reactions in individuals with fungal sensitivities.
• Rare: Purpura and bleeding manifestations have been reported in case studies involving excessive consumption, attributed to the antiplatelet activity of adenosine.

Quality and Safety Concerns

• Bongkrekic acid contamination risk: In 2020, a fatal poisoning event in Heilongjiang Province, China, was linked to prolonged soaking of Heimuer in contaminated water, which allowed proliferation of Burkholderia gladioli pv. cocovenenans bacteria producing bongkrekic acid, a highly lethal mitochondrial toxin. The toxin was produced by the bacteria, not by the mushroom itself. This incident led to Chinese government food safety warnings about proper handling of rehydrated Heimuer: dried Heimuer should be soaked for no more than 2-4 hours, should not be left at room temperature for extended periods, and should be discarded if slimy or off-smelling.
• Heavy metals: Cultivated Heimuer generally has lower heavy metal content than wild-harvested specimens. Commercial products should be tested for cadmium, lead, and arsenic, which can be absorbed from contaminated substrates.
• Pesticide residues: Large-scale cultivation in China may involve pesticide use. Organic-certified products are available and may reduce this concern.

Clinical Dosage

Traditional Decoction (Chinese Pharmacopoeia)

• Standard dose: 6-12 g/day of dried fruiting body, prepared as a decoction (simmered in water)
• This is the official dose listed in the Chinese Pharmacopoeia (2020 edition)

Dietary Consumption (Food as Medicine)

• Typical culinary dose: 5-15 g dried Heimuer per serving (approximately 50-150 g rehydrated weight)
• Traditional preparation: Dried Heimuer is soaked in cold or warm water for 30 minutes to 2 hours until fully rehydrated, then added to soups, stir-fries, salads, or braised dishes
• Safety note: Do not soak for more than 4 hours at room temperature to prevent bacterial contamination (see bongkrekic acid risk above)

Polysaccharide Extract

• Clinical trial dose: 1-3 g/day of polysaccharide extract (based on published clinical studies)
• This dose form has been used in the lipid-lowering and hemorheological clinical trials

Dried Fruiting Body Powder

• Estimated dose: 5-10 g/day of dried powder in divided doses
• Used in some dietary supplement products and traditional preparations

Form Selection Guidance

For cardiovascular applications, the traditional dietary consumption (as cooked food) is the most well-established form, supported by centuries of TCM practice and the largest exposure base. Concentrated polysaccharide extracts have been used in clinical trials for lipid-lowering applications and may provide more consistent dosing. The adenosine content (relevant to antiplatelet effects) is present in both whole-food and extract forms. Hot-water extraction captures the polysaccharide fraction; the melanin and dietary fiber fractions are best obtained from whole-food consumption.

Sources

• Wu F, Yuan Y, He SH, Bandara AR, Hyde KD, Malysheva VF, et al. Global diversity and taxonomy of the Auricularia auricula-judae complex (Auriculariales, Basidiomycota). Mycol Prog. 2015;14:95
• Hammerschmidt DE. Szechwan purpura. N Engl J Med. 1980;302(19):1191-1193
• Chen G, Luo YC, Ji BP, Li B, Guo Y, Li Y, Su W, Xiao ZL. Effect of polysaccharide from Auricularia auricula on blood lipid metabolism and lipoprotein lipase activity of ICR mice fed a cholesterol-enriched diet. J Food Sci. 2008;73(6):H103-H108
• Yoon SJ, Yu MA, Pyun YR, Hwang JK, Chu DC, Juneja LR, Mourão PA. The nontoxic mushroom Auricularia auricula contains a polysaccharide with anticoagulant activity mediated by antithrombin. Thromb Res. 2003;112(3):151-158
• Fan L, Ding S, Ai L, Deng K. Antitumor and immunomodulatory activity of water-soluble polysaccharide from Inonotus obliquus. Carbohydr Polym. 2012;90(2):870-874
• Zhao S, Rong C, Liu Y, Xu F, Wang S, Duan C, et al. Extraction of a soluble polysaccharide from Auricularia polytricha and evaluation of its anti-hypercholesterolemic effect in rats. Carbohydr Polym. 2015;122:39-45
• Ma Z, Wang J, Zhang L, Zhang Y, Ding K. Evaluation of water soluble beta-d-glucan from Auricularia auricular-judae as potential anti-tumor agent. Carbohydr Polym. 2010;80(3):977-983
• Yu M, Xu X, Qing Y, Luo X, Yang Z, Zheng L. Isolation of an anti-tumor polysaccharide from Auricularia polytricha (wood ear) and its effects on macrophage activation. Eur Food Res Technol. 2009;228(3):477-485
• Chinese Pharmacopoeia Commission. Pharmacopoeia of the People’s Republic of China. Vol 1. 2020 Edition
• Li Shizhen. Bencao Gangmu (Compendium of Materia Medica). 1596. Mu Er category
• Wasser SP. Medicinal mushroom science: current perspectives, advances, evidences, and challenges. Biomed J. 2014;37(6):345-356
• Cheung PCK. The nutritional and health benefits of mushrooms. Nutr Bull. 2010;35(4):292-299
• Mau JL, Chao GR, Wu KT. Antioxidant properties of methanolic extracts from several ear mushrooms. J Agric Food Chem. 2001;49(11):5461-5467
• Luo Y, Chen G, Li B, Ji B, Guo Y, Tian F. Evaluation of antioxidative and hypolipidemic properties of a novel functional diet formulation of Auricularia auricula and Hawthorn. Innov Food Sci Emerg Technol. 2009;10(2):215-221
• Wu F, Dai YC. Auricularia heimuer, a new species of Auricularia (Auriculariales, Basidiomycota) from China. Phytotaxa. 2015;209(1):86-90
• Huo J, Wu J, Zhao M, Sun W, Sun J, Li H, Huang M. Immunomodulatory activity of a novel polysaccharide extracted from Auricularia polytricha in RAW264.7 macrophages. Int J Biol Macromol. 2020;143:423-432

Connections

• Auricularia auricula-judae (Jelly Ear): Jelly Ear is the true European Auricularia species, now recognized as taxonomically distinct from A. heimuer. Most of the global “wood ear” trade and virtually all TCM Mu Er research actually concerns A. heimuer, not A. auricula-judae. The pharmacological profiles may differ between species, but comparative studies are limited. When reading literature on “Auricularia auricula-judae” from Chinese sources, it almost certainly refers to A. heimuer.
• Auricularia polytricha (Cloud Ear): Cloud Ear is another commercially cultivated Auricularia species, sometimes sold interchangeably with A. heimuer. It is generally lighter in color, thinner in texture, and may have a somewhat different bioactive profile, though comparative pharmacological data are limited.
• Tremella fuciformis (Snow Fungus): Tremella is frequently paired with Heimuer in TCM formulations and Chinese culinary medicine. Tremella is classified as a yin-nourishing, lung-moistening medicine with complementary properties to Heimuer’s blood-vitalizing activity. The combination is a classic TCM pairing for respiratory and cardiovascular support.
• Ganoderma lucidum (Reishi): Reishi shares adenosine-mediated antiplatelet pharmacology with Heimuer, connecting the two species through overlapping cardiovascular mechanisms. Both are TCM qi and blood tonics, though Reishi is primarily classified as an immune-modulating shen tonic while Heimuer is primarily a blood-vitalizing food medicine.
• Cardiovascular medicinal fungi: Heimuer occupies a unique position among medicinal fungi as the species with the strongest specific cardiovascular evidence base, supported by both TCM tradition and modern clinical studies. Its anti-atherosclerotic profile (antiplatelet + lipid-lowering + hemorheological improvement) provides a multi-target cardiovascular benefit that is unusual for a single dietary intervention.
• Food-as-medicine paradigm: Heimuer exemplifies the TCM food-as-medicine (yao shan) paradigm, where dietary staples serve simultaneously as preventive medicines. Its massive production volume (>6 million tonnes/year) and daily consumption by hundreds of millions of people in East Asia make it one of the most consumed medicinal fungi on Earth, albeit primarily as food rather than as a concentrated therapeutic agent.