Exploring the Traditional and Scientific Uses of Chaga Mushroom:
A Comparative Review
Silvia of Thrace
(Larissa Notter)
May 5, 2023
Introduction
Chaga, Inonotus obliquus, is found on birch trees. It takes at least five to ten years for the mushrooms to grow and will only release its spores once the birch has died and fallen. Within the last ten years, the spotlight has been shown on this burnt looking fungus, giving rise to many herbalists putting it in their repertoire of herbal medicines. It has also led to more scientific studies which can help inform the public about the uses of traditional medicine that actually work.
The goal of this paper is to provide a comparative analysis of Chaga’s traditional uses and scientific research revealing both similarities and differences highlighting the need for a balanced approach that integrates traditional knowledge with scientific evidence for a comprehensive understanding of Chaga’s potential health benefits with environmental conservation in mind.
History of Chaga
The history of this mushroom dates all the way back to the 12th century with the most famous healing being of Vladimir Monomakh’s lip cancer (Spinosa 2012). It has been used by the Chinese, Japanese, Russians, Koreans, and Baltic Peoples for many different uses (Géry, A. et al 2018). The Indigenous Alaskans used it mostly to burn as tinder. Some evidence has been shown for them using Chaga as a tea for medicinal purposes (Deur, D., Evanoff, K. & Hebert 2020). Most of the historical use has come from Russia (Géry, A. et al 2018).
Unfortunately in my research I could not find any primary sources of the historical uses, at least none that are translated into English. All of the scientific studies are peer reviewed from sources such as PubMed, NCBI, and different reputable scientific journals.
How Chaga is Processed for Medicinal Purposes
The general wisdom is to harvest in cold winter months sustainably using a large chisel striking down on the top of the conk with a clean incision that lies in line with the bark of the birch tree. By doing this, the conk will grow back in 3-5 years. The fruiting body is then dried and chunked or powdered to be used in decoctions, teas, or tinctures.
The process of making a decoction involves boiling an herb, bark, or root in water between five and thirty minutes, depending on the substance. Decoctions help break down matter and allow the medicinal properties to be extracted. For a medicinal tea, pour boiling water over the herb and let steep, covered for 10-15 minutes. Chaga can be made this way, but it may not extract the medicinal properties.
Tinctures can be made by putting the macerated herb in alcohol for two weeks, shaking it up at least once a day. Vodka works well because the tincture will not need to be watered down when finished. However, the hardness of chaga means that the medicinal properties are not fully extracted with the traditional extraction method. Most herbalists prefer a double extraction. The process of double extracting involves boiling the herb in water. Then both the water and herbs are put into alcohol, in this case something stronger like grain alcohol due to water being added (Visser 2020). Dr. Spady, a local herbalist, uses a triple extraction method, which he purports to bring out even more medicinal properties. There are many different types of triple extraction that I found in research which are different from his technique. Dr. Spady starts his triple extraction by slow-cooking the Chaga between 130-140 degrees. After that, the water is put aside and the chunks are boiled for three hours. That water is put aside and the same chunks are put in alcohol of 75-90% for two weeks. Once the two weeks have passed, both sets of water, alcohol, and Chaga chunks are put together and let set for three to four months.
Cancer
Cancer is a devastating disease that has many forms. It is not just one disease and makes it difficult for the medical community to treat, prevent, or cure. When I was younger, I thought that cancer is a newer type of disease, but as I study more about herbs, the more I realize that it has been around for all of time.
According to Beverly Gray, Chaga has been used to combat cancer. Chaga contains two compounds that have anticancer effects. The first is polysaccharides. The second is triterpenoids.
The polysaccharides found in multiple studies are mannose, rhamnose, glucose, galactose, xylose, and arabinose (Lu, et al 2021). These are formed in a triple helix which makes it the most temperature stable formation. This means that the polysaccharides are not going to be destroyed by heat and can be safely extracted using heating methods to bring out this type of medicinal property. It is thought that the triple helix is attributed to the immune activity of Chaga extracts (Lu, et al 2021).
Triterpenoids are a type of terpenoid, which is a type of terpene. Terpenes are essential oils that are responsible for the fragrance of most plants. (Johnson 2020) The triterpenoids found in French, Thai, Finnish, Russian, and Chinese Chaga were inonotsuoxide A, inotodiol, trametenolic acid, and lanostérol. Inotodiol is found to have the most therapeutic activities against cancer (Géry, A. et al 2018 under Discussions and Conclusions).
The actions of Chaga extract on cancer is debated. Currently the two theories are antioxidative for preventing the development of cancer and the other is stimulating the immune system to help rid the body of cancer cells. It is difficult to determine which of these it is at this time as the studies have been human cancer cells in vitro (studied in a test tube) and cancers in vivo (in living organisms) have been in mice. More studies are needed to see what will actually work in humans.
Ulcers
Ulcers can come in several different varieties. There are the stomach (peptic) ulcers, which can be caused by either too much acid, dehydration, or something wrong with the lining of the stomach. Then there are the ulcers which have to do with circulation: arterial and venous. The last two are mouth and genital ulcers.
McDarris states that texts from the 1500’s claims Chaga was used to treat ulcers (McDarris 2021). It does not specify which type of ulcers, but for the purpose of this paper, it will be assumed that it is the arterial and venous ulcers which cause wounds that do not heal. The hypothesis supporting this claim points to the polysaccharides and phenols.
A study done by Sharifi-Rad, et al in 2020 showed a polysaccharide, β-glucans, decreased healing time by 48 percent. In other mushrooms explored in this study, β-glucans were shown to be effective
…through increasing the collagen regeneration, macrophage and fibroblast migration, and wounds epithelialization in STZ-induced diabetic rats.
(Sharifi-Rad, et al 2020, under Mushrooms Effects: Emphasis on Wound Healing Potential)
Chaga is shown to have between 13.7g and 15.3g of β-glucans per 100g of mushroom used in extract (Rhee, et al 2008). More studies need to be done to verify if this amount is effectual in wound healing. Sharifi-Rad, et al 2020 noted that Khamlue et al 2012 Auricularia auricula studied and found 1g of polysaccharides (assumed to be β-glucans) to be effective in healing a pig skin model.
The phenolic compounds found in Chaga were mostly antioxidants, 4-(3,4-dihydroxyphenyl)but-3-en-2-one, 4-hydroxy-3,5-dimethoxybenzoic acid, 3,4-dihydroxybenzaldehyde, 4-hydroxybenzene-1,3-dioic acid and 3,4-dihydroxybenzoic acid. The phenol 4-hydroxybenzene-1,3-dioic acid was found to have properties that protected cells from getting DNA damage. (Hwang, B., Lee, IK. & Yun, BS 2016).
Tuberculosis
The same Medieval texts from above also claim that Chaga can be used for tuberculosis (McDarris 2021). The bacteria that causes tuberculosis is called Mycobacterium tuberculosis There are studies showing that Chaga does have antimicrobial properties (Glamočlija, Jasmina et al 2015), but none that point specifically to being antimycobacterial.
Heart disease
Spinosa states that the Russians have used Chaga as a tea to help with heart disease. More recent research has been done specifically on the Inonotus obliquus extract (IOE). One of the downsides to this study is that the research is performed on rats. However, studies like this can lead to studies in humans.
Researchers found that IOE helps heart disease by relieving endoplasmic reticulum (ER) stress. Cardiomyocytes, the heart muscle cells which help in the contraction of the heart itself, were protected from oxidative stress. The IOE also helped prevent cardiomyocyte death after damage. The tincture has been shown to downregulate the expression of ER stress-related markers (GRP78, p-PERK, p-eIF2α, CHOP and caspase-12), which is hypothesized to help reactivate SIRT1. SIRT1 is thought to have cardioprotective properties. (Wu, et al 2020)
Liver disease
Spinosa states that the Khanty used Chaga in a number of ways, including for liver disease. He mentions they prepared is as both tea and smoking as a way to prevent disease.
Shen, et al. 2022 found that the polysaccharides of Chaga are active along the liver kinase B 1(LKB1)/AMPK pathway. This pathway has been shown to be important in the liver for diabetes patients (Shackelford et al 2009). It speaks more to the build up of lipids, or fats, in the liver rather than liver disease itself.
A different study did show that Chaga protected the liver cells when mice were put on a diet that induced inflammation in the liver (Yang, et al 2021), however it was not in relation to liver disease.
Other uses
In my research I came across several sources that discussed the compounds found in Chaga to be effective, at least in mice, against type 2 diabetes as well as hyperlipidemia, or high cholesterol.
Hypoglycemic:
As has been seen in previous sections, the polysaccharides were involved with treating mice with type 2 diabetes. The mechanism might supposedly be via the regulation of the PI3K/Akt and AMPK/ACC signal pathways(Lu, et al, 2021)
Hypolipidemic:
Polysaccharides found in Chaga may inhibit lipid peroxidation (Raedschelders K, Ansley DM and Chen DD 2012). Lipid peroxidation is a problem because free radicals “steal” electrons from lipids. This causes cell damage. Mice that were taking a chaga extract showed decreased lipids, including total cholesterol, triglycerides, and low-density-lipoproteins (Yang, et al 2021).
Sustainability
As with any herb that becomes known to the public as a “wonder cure all”, the worry of herbalists is conservatism and how sustainable or feasible it is to make it available to everyone. The proper way to sustainably harvest Chaga is detailed in the beginning of this paper. However, many people cut into the tree, seemingly with no regard to the future of either the mushroom or the tree itself. These same people tend to harvest it when it is too small. If Chaga is harvested when too small, it is less likely to produce spores that are needed for reproduction.
Another worry is people harvesting the wrong type of conk. There are many posts on Facebook stating that someone is so happy they found a huge Chaga only for it to be a different type of polypore altogether. Then you have the people who harvest that and sell it as Chaga online. Thankfully, most of what is mistaken as Chaga is harmless.
Chaga takes a long time to grow, which makes it difficult to cultivate. Even those who have tried to cultivate it say that the product is inferior to wild harvested.
Conclusion
Chaga is a parasitic mushroom that grows on birch trees in Alaska. It has been used traditionally and historically for cancer, liver disease, heart disease, ulcers,and tuberculosis. There are several ways to prepare it, but two of the most popular are decoction and tincture.
Comparing the traditional uses to what scientific evidence has found is useful to herbalists so they can back up their knowledge with science. It can help lead to better health through herbs. While those in history did not have the knowledge of how herbs and mushrooms worked, they would find out through experimentation that something did work.
By comparing the historic uses against available scientific studies, I have found that there is evidence to support that Chaga extracts can be helpful in all of the above diseases, except for Tuberculosis. There were no specific studies supporting Chaga to be antimycobacterial, which is the drug class used to treat tuberculosis. Additionally, I found that it could also be helpful for those who are trying to lower their blood sugars as well as their cholesterol levels.
Even with the scientific evidence that Chaga is a useful tool in an herbalists arsenal, one may want to limit the use of it anyways. The sustainability of broad use is a concern because Chaga takes so long to grow and is difficult to cultivate. There are many herbs that have been lost to time due to lack of sustainable harvesting. Chaga would be sorely missed if it were to be overharvested.
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