Supplement
Chaga is a dark fungus that grows on birch trees and is traditionally brewed as a tea, containing polyphenols, melanin, and beta-glucans that give it antioxidant properties. The evidence is limited, but lab studies found chaga extracts slowed the growth of several cancer cell types, and animal studies found tumors grew less. No human trials have tested this, though, and one case report linked very heavy chaga use to kidney damage from its oxalates.
Sources: PMID 20607084; PMID 22135902
- Updated
- How we grade
- 17 studies cited
- Best evidence
- Grade C
- Conditions studied
- 2
- Outcomes
- 8
- Graded outcomes
- 0026
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
General
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Antitumor Effects Multiple in vitro studies show chaga extracts inhibit proliferation of various cancer cell lines including lung adenocarcinoma (A549), colon, breast, and liver cells. Betulinic acid from chaga induces apoptosis. Animal studies demonstrate tumor growth reduction. No human clinical trials exist. | Improves (the measure goes down) | Moderate effect | 7 studies | |||
Studies that measured antitumor effects
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| Antiviral Activity In vitro studies show chaga extract inhibits hepatitis C virus replication in cell cultures. A separate study demonstrated activity of aqueous extracts against human immunodeficiency virus. Both findings are limited to cell culture models with no human data. | Improves (the measure goes up) | Small effect | 5 studies | |||
Studies that measured antiviral activity
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| Anti-inflammatory Effects In vitro and animal studies demonstrate anti-inflammatory activity of chaga extracts, including reduced inflammatory markers. One study compared chaga with germinated brown rice extracts and found significant anti-inflammatory effects. No human clinical evidence. | Improves (the measure goes down) | Small effect | 4 studies | |||
Studies that measured anti-inflammatory effects | ||||||
| Immune Function Preclinical studies show beta-glucans from chaga activate macrophages and natural killer cells, enhancing innate immune function. Some evidence of cytokine modulation. No human trials have been conducted. | Improves (the measure goes up) | Small effect | 3 studies | |||
Studies that measured immune function
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| Blood Glucose In alloxan-induced diabetic mice, chaga water extract reduced blood glucose levels and improved lipid profiles. Polysaccharides produced under optimized fermentation conditions also showed hypoglycemic activity. Proposed mechanism involves alpha-glucosidase inhibition. No human data. | Improves (the measure goes down) | Moderate effect | 3 studies | |||
Studies that measured blood glucose
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| Acetylcholinesterase Inhibition Triterpenoids isolated from chaga fruiting bodies act as bivalent and dual inhibitors of both acetylcholinesterase and butyrylcholinesterase in vitro, suggesting potential relevance to neurodegenerative conditions. No animal or human data on cognitive outcomes. | Changes; see studies | Small effect | 2 studies | |||
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| Kidney Damage Risk (Oxalate Nephropathy) A case report documented chaga mushroom-induced oxalate nephropathy presenting as nephrotic syndrome. Chaga contains high levels of oxalates, and excessive consumption may cause kidney injury. This is an adverse effect warranting caution. | Worsens (the measure goes up) | Moderate effect | 3 studies | 1 person | ||
Studies that measured kidney damage risk (oxalate nephropathy) | ||||||
Key findings
- Antitumor EffectsImproves (the measure goes down)
- Antioxidant ActivityImproves (the measure goes up)
- Antiviral ActivityImproves (the measure goes up)
Safety notes in the studies
- This is an adverse effect warranting caution.
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- Grade C
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Studies cited
17 studies from PubMed
- Chemical Content and Cytotoxic Activity on Various Cancer Cell Lines of Chaga (Inonotus obliquus) Growing on Betula pendula and Betula pubescens.
- Antidiabetic activity of Inonotus obliquus water extract in alloxan-induced diabetic mice.
- Comparison of Bioactive Secondary Metabolites and Cytotoxicity of Extracts from Inonotus obliquus Isolates from Different Host Species.
- Triterpenoids as bivalent and dual inhibitors of acetylcholinesterase/butyrylcholinesterase from the fruiting bodies of Inonotus obliquus.
- Chaga mushroom-induced oxalate nephropathy that clinically manifested as nephrotic syndrome: A case report.
- Comparison of Polysaccharides Extracted from Cultivated Mycelium of Inonotus obliquus with Polysaccharide Fractions Obtained from Sterile Conk (Chaga) and Birch Heart Rot.
- Simultaneous Use of Stimulatory Agents to Enhance the Production and Hypoglycaemic Activity of Polysaccharides from Inonotus obliquus by Submerged Fermentation.
- Chaga (Inonotus obliquus), a Future Potential Medicinal Fungus in Oncology? A Chemical Study and a Comparison of the Cytotoxicity Against Human Lung Adenocarcinoma Cells (A549) and Human Bronchial Epithelial Cells (BEAS-2B).
- Inonotus obliquus - from folk medicine to clinical use
- Antiviral activity of aqueous extracts of the birch fungus Inonotus obliquus on the human immunodeficiency virus.
- Oxalate nephropathy from excessive Chaga mushroom consumption
- Anti-oxidant and anti-inflammatory activities of Inonotus obliquus and germinated brown rice extracts.
- Antiviral activity of Inonotus obliquus fungus extract towards infection caused by hepatitis C virus in cell cultures.
- Antitumor activity of water extract of Inonotus obliquus
- Antioxidant and antitumor activities of Chaga extract (Inonotus obliquus)
- Identification of Inonotus obliquus and analysis of antioxidation and antitumor activities of polysaccharides.
- Immunomodulatory activity of the water extract from medicinal mushroom Inonotus obliquus