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Anti-diabetic Effects of Chaga Mushroom

 

    I have an aunt who is very keen on health. During my recent home visit, she showed me a box of black chunk pieces asking if they were indeed having many health benefits as indicated on the box. The black stuff in the box was Inonotus obliquus, also known as Chaga mushroom.

 

    As early as the 16th century, Inonotus obliquus was used as a folk medicine in Russia, Siberia, and some occidental countries. It is a kind of fungus that mostly parasitizes on living trunk of birch trees in the cold circumboreal region of the northern hemisphere areas; it is also named Chaga mushroom due to its irregularly formed sterile conk with burnt charcoal-like appearance. Owing to abundant melanin, the sclerotium and mycelium are mostly black. Among the extracts from Inonotus obliquus, Inonotus obliquus polysaccharide is supposed to be one of the major bioactive components in Inonotus obliquus, which possesses antitumor, antioxidant, anti-virus, hypoglycemic, and hypolipidemic activities (1). This blog is focused on the studies that have reported on the anti-diabetic effects of Chaga mushrooms.

 

    Diao et al. showed that feeding Chaga mushroom polysaccharides at 10, 20, and 30 mg/kg to diabetic rats for 6 weeks reduced blood glucose levels and restored the structure of β-cells after diabetes-induced cellular damage. There was a dose relationship for glucose reduction. The glucose level was lowered by more than 50% in the highest dose of the Chaga mushroom treatment group (10.1 ± 3.2 mmol/L) compared to that of the diabetic group (22.2 ± 2.2 mmol/L). Chaga mushroom polysaccharides also lowered the level of lipid peroxidation products (such as low-density lipoprotein), whereas the high-density lipoprotein cholesterol level was enhanced. The highest dose of Chaga mushroom polysaccharides resulted in a similar lipid profile as that of the control normal rats, which was lower than those of the diabetic control group. The total cholesterol levels for control normal rats, diabetic rats, and 30 mg/kg Chaga-treated rats were 4.30 ± 0.79, 10.40 ± 0.85, and 4.34 ± 0.80 mmol/L, respectively, and the triglyceride levels were 0.80 ± 0.11, 1.23 ± 0.10, 0.78 ± 0.09 mmol/L, respectively (2).

 

    Wang et al. reported that Chaga mushroom polysaccharides enhanced the serum levels of insulin and alleviated the metabolic derangement of glucose enzymes in diabetic mice. Three Chaga mushroom polysaccharides treatment groups were orally fed to diabetic mice at doses of 300, 600, and 900 mg/kg per day, respectively, for 4 weeks. Chaga mushroom polysaccharides (900 mg/kg) exerted significant hypoglycemic effects on diabetic mice (p < 0.01) with a glucose reduction rate of 49.9%, which was better than the rosiglitazone-treated group (26.90%) compared to the diabetic control. A remarkable disorder in lipid profiles was observed in induced diabetic mice. After the treatment of Chaga mushroom polysaccharides (900 mg/kg), significant decreases in serum triglycerides, total cholesterol, and LDL-cholesterol levels were observed with reduction rates of 60.89%, 21.50%, and 60.72%, respectively, and significant increases in HDL-cholesterol with the increase rate of 35.52% compared to the diabetic control

(p < 0.05) (3).

 

    Zhang et al. fed Chaga mushroom extract to diabetic mice orally at 100, 250, and 500 mg/kg for 8 weeks. Chaga mushroom extract at 250 mg/kg and 500 mg/kg doses significantly alleviated blood glucose and insulin resistance with the 500 mg/kg dose resulting in a 34% lowered blood glucose level compared to that of the diabetic control group. Tissue staining revealed islet tissue damage and bleeding in the pancreatic tissues of the diabetic control group, with islet atrophy and structure deterioration, and the extract (250 and 500 mg/kg) attenuated the islet injury and β-cell damage. In the high dose 500 mg/kg treatment group, the pancreatic tissue structure was almost restored to normal, the number of injured adult cells was significantly reduced, and the islet cells were protected (4).

 

   The extract (250 mg/kg and 500 mg/kg) also increased liver glycogen content and high-density lipoprotein cholesterol levels while decreasing total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels. The serum lipid profiles in the high dose 500 mg/kg group were significantly improved compared to those of the diabetic without treatment group. The total cholesterol, triglyceride, and LDL-cholesterol levels decreased by 20.09%, 48.91%, and 51.21%, respectively (p < 0.05), whereas HDL-cholesterol levels increased by 49.54% (p < 0.05). There was a dose effect within the three test doses of 100, 250, and 500 mg/kg. 250 mg/kg had an obvious anti-diabetes effect, and the effect of 500 mg/kg dose was the same as that of metformin treatment (4).

 

    The polysaccharides used in these studies were extracted using different methods, some from culture grown from seeds in a flask for days, while others were extracted from the Chaga mushroom directly. That was why the doses were quite different among different reports. This dosing thing is very relevant for practical everyday use since as a folk medicine, Chaga mushroom is typically used by soaking in the hot water for drinking. How much of the bio-actives can come out of the soaking process can well be influenced by how much is added to start with and how long the soaking process is.

 

    No matter what dosing the reports were using, the results from the diabetic animal studies suggested that Chaga mushroom could be a promising functional food and even considered as a drug for the treatment of diabetes. Chaga mushroom extract could ameliorate insulin resistance and lipid metabolism disorders, and lower blood glucose levels in diabetic mice (2-4).

 

    While Chaga mushrooms are generally considered safe when consumed as food or in moderate amounts as supplements, excessive intake may lead to potential health issues. For example, a case of end-stage renal disease had been reported after long-term taking of Chaga mushroom. A review of kidney biopsy findings was consistent with chronic tubulointerstitial nephritis with oxalate crystal deposits and drug history revealed long-term exposure to Chaga mushroom powder. The association between Chaga mushrooms and oxalate nephropathy was suspected to be caused by the extremely high oxalate content (14.2/100 g) in Chaga mushrooms. Chaga mushroom had been warned as a potential risk factor for chronic kidney disease considering its high oxalate content (5).

 

    A word of caution is that Chaga mushrooms might lower blood sugar levels, which can be a concern for people with diabetes or those taking medications to lower blood sugar. Individuals with diabetes must monitor their blood sugar levels closely if using Chaga supplements. It may also have interactions with medications for diabetes management. It would be wise to consult with a healthcare professional before using Chaga supplements to avoid any potential adverse interactions.

 

    Chaga mushrooms can also stimulate the immune system, which may be beneficial for cancer prevention, but it could worsen symptoms for those with autoimmune disorders or conditions where the immune system attacks healthy tissues.

 

    Based on the reading of the published papers, I would agree with one of the reviews (6) that Chaga mushroom fits the definition of functional food and has a potentially positive effect on health beyond basic nutrition, however, more animal and human studies are needed. Currently, anti-cancer effects have only been proven in cell culture studies. It has the potential for Chaga mushroom extracts to be included in cancer therapies in the future, but animal studies are needed. For the anti-diabetic effects of Chaga mushroom, it is very promising as shown in animal studies, but human studies are needed.

 

    So to answer my aunt’s question: the various promoted health benefits on the box are yet scientifically proven, which still need more scientific research to verify. It may take many years to prove the effectiveness of folk medicine using scientific research.

 

    While the scientific research on Chaga mushrooms is ongoing, and some potential side effects may not be well-documented, if you are considering using Chaga mushrooms as a dietary supplement or for medicinal purposes, it is wise to consult with healthcare professionals for any potential medicine interactions.  If you decide to try it after all, start at a very low dose.

 

References:

 

  1. Lu Y, Jia Y, Xue Z, Li N, Liu J, Chen H. Recent Developments in Inonotus obliquus (Chaga mushroom) Polysaccharides: Isolation, Structural Characteristics, Biological Activities and Application. Polymers (Basel). 2021 Apr 29;13(9):1441. doi: 10.3390/polym13091441. PMID: 33947037; PMCID: PMC8124789.

  2. Diao BZ, Jin WR, Yu XJ. Protective Effect of Polysaccharides from Inonotus obliquus on Streptozotocin-Induced Diabetic Symptoms and Their Potential Mechanisms in Rats. Evid Based Complement Alternat Med. 2014;2014:841496. doi: 10.1155/2014/841496. Epub 2014 Jun 30. PMID: 25093030; PMCID: PMC4100277.

  3. Wang J, Wang C, Li S, Li W, Yuan G, Pan Y, Chen H. Anti-diabetic effects of Inonotus obliquus polysaccharides in streptozotocin-induced type 2 diabetic mice and potential mechanism via PI3K-Akt signal pathway. Biomed Pharmacother. 2017 Nov;95:1669-1677. doi: 10.1016/j.biopha.2017.09.104. Epub 2017 Oct 6. PMID: 28954386.

  4. Zhang Z, Liang X, Tong L, Lv Y, Yi H, Gong P, Tian X, Cui Q, Liu T, Zhang L. Effect of Inonotus obliquus (Fr.) Pilat extract on the regulation of glycolipid metabolism via PI3K/Akt and AMPK/ACC pathways in mice. J Ethnopharmacol. 2021 Jun 12;273:113963. doi: 10.1016/j.jep.2021.113963. Epub 2021 Feb 26. PMID: 33640441.

  5. Lee S, Lee HY, Park Y, Ko EJ, Ban TH, Chung BH, Lee HS, Yang CW. Development of End Stage Renal Disease after Long-Term Ingestion of Chaga Mushroom: Case Report and Review of Literature. J Korean Med Sci. 2020 May 18;35(19):e122. doi: 10.3346/jkms.2020.35.e122. PMID: 32419395; PMCID: PMC7234858.

  6. Szychowski KA, Skóra B, Pomianek T, Gmiński J. Inonotus obliquus - from folk medicine to clinical use. J Tradit Complement Med. 2020 Aug 22;11(4):293-302. doi: 10.1016/j.jtcme.2020.08.003. PMID: 34195023; PMCID: PMC8240111.

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