The chaga mushroom has become quite popular in recent years due to increased marketing of “medicinal mushrooms” via supplements, teas, tinctures, powders, and even coffee mixes. If you’re wondering what the scoop is on this interesting fungus, you’ve come to the right place.
In this guide, we’ll cover the fungal classification of chaga mushrooms, their native distribution, where they grow, their ecological roles, traditional and current human uses, their cultivation status, and current research on potential medicinal benefits.
The Chaga Mushroom: Fungal Classification, Native Distribution, and Ecological Roles
The chaga mushroom (Inonotus obliquus) is a unique-looking basidiomycete fungus that belongs to the Hymenochaetaceae family. If you happen upon this polyporous mushroom in a forest, upon first glance, you might not even realize you are looking at a mushroom, as Inonotus obliquus often looks more like a tumor growing from the heart of a tree, rather than the fruiting body of a fungus.
This mushroom is native to arboreal regions of the northern hemisphere across Russia, parts of northern Europe and Asia, Canada, Alaska, and the northernmost regions of the continental US. In these regions, you can find Inonotus obliquus year-round, but new formations grow in the summer and fall.
Chaga is a parasitic fungus that causes white heartwood rot most frequently on birches, and less commonly on oaks, poplars, alders, ashes, and maples. Once the tree dies, this mushroom also fills a saprobic role, deriving nutrients from the organic matter of the dead tree. As a white rot fungus, Inonotus obliquus contributes to crucial nutrient recycling and carbon sequestration.
The Chaga Mushroom: Traditional and Current Medicinal Uses and Research
As mentioned above, you may be familiar with this mushroom from various health industries marketing supplements, powders, tinctures, or teas that contain the ground fruiting body or extracts from the fruiting body or mycelium of Inonotus obliquus.
The history of people using chaga in hopes of treating various ailments or to benefit health dates much further back, however, than the current Western trend. Particularly in Siberia and Russia, people have used chaga to target a range of ailments and illnesses from gastrointestinal diseases to tumors, respiratory illnesses, and fatigue. Please note that discussing the historical use of a mushroom for medicinal purposes is not confirmation of any actual medicinal properties.
However, with that being said, widespread research within the past 10 years on Inonotus obliquus does support that this fungus contains a number of potentially beneficial compounds. Through cell-culture studies (in vitro) and animal model studies (in vivo), researchers have found this fungus contains compounds that may display a number of potentially beneficial effects including antiviral, antioxidant, antidiabetic, antiparasitic, neuroprotective, anti-inflammatory, and anti-tumor. To date, no official studies have conducted human trials on the potential medicinal effects of this fungus. As interest and research grow, we may see this change in the coming years.
Considerations on Consuming Chaga for Medicinal Purposes
If you’re excited about trying chaga as a medicinal mushroom, it’s important to understand that identifying bioactive compounds in a fungus, extracting them via a number of methods, and understanding/optimizing the bioavailability of those compounds are all separate questions and processes. Even if there is 100% confirmation that chaga contains compounds that can have various beneficial health effects for humans, it is likely these compounds need to be extracted and prepared via specific methods to actually have an effect. Additionally, remember that many proven medicinal compounds can also cause harmful side effects depending on factors such as our individual brain chemistry, dosages, length of use, or interaction with other medicines.
All of this is to say it’s best to be cautious with claims made by companies marketing these products. The company should describe what part of the fungus is being used, their extraction methods, and cite research. It’s best to seek the guidance of a qualified medical professional if you’re interested in consuming chaga medicinally.
Preparing Chaga Tea from a Fresh Harvest
Chaga tea is one of the most common and historically-rooted preparations of this mushroom. There are a few ways you can prepare this mushroom for brewing. One method involves cleaning, removing the hard exterior, and allowing the chunks of flesh to dry for about a month until they are brittle and light. From this stage, you can brew the tea from 1-inch-sized chunks. You can also grind it into a coarse or fine powder prior to brewing. Many people add honey to their chaga tea as the taste can be a bit bitter. You may also notice the tea has a nutty or vanilla-like taste to it.
Identifying the Chaga Mushroom
If you live in the regions the chaga mushroom is native to, you can search for it year-round. Some folks prefer to hunt in winter as the lack of foliage aids in spotting the mushroom. Since this fungus primarily grows on birch species, you may have the best luck hunting in forests where birches are prominent.
When searching for this mushroom, you’ll want to look up along the trunk of standing trees. Look for what will appear to be a crusty, blackened growth erupting from the trunk. The fruiting body often averages 12-18 inches across. Though, some can grow much larger. The shape of the mushroom is typically irregular and the exterior is dry, textured, and rough.
The flesh is a lovely orange-brown that you may see through cracks in the exterior layer of the mushroom. The flesh has more of a corky texture and tends to smell earthy and bitter.
Is the Chaga Mushroom Overharvested and Can You Cultivate It?
As Inonotus obliquus has become popular worldwide, some have become concerned about the possibility of the overharvesting of this fungus. This extremely slow-growing mushroom can take up to 20 years to reach its full size. After harvesting, ideally with a couple of inches left on the trunk, the fruiting body will start to regrow ever so slowly. This slow rate of growth coupled with the high demand for chaga-based products could certainly cause problems for wild populations of this fungus.
As of 2018, the Global Fungal Red List Initiative lists Inonotus obliquus as a fungus of least concern. This assessment is due to the current thriving population numbers of the fungus and its preferred host trees. The assessment does state that overharvesting in local areas is certainly possible. Additionally, long-term reassessments should occur due to the rising popularity of this mushroom.
The question of cultivating chaga is a bit complicated. While cultivation is possible, growers mostly find success in inoculating suitable stands of birch trees. This in comparison to growing them in a laboratory setting. Additionally, because growth time is so slow, it’s unlikely that commercial cultivation of chaga will replace commercial harvesting anytime soon.
One study from 2021 detailed some success in inoculating Inonotus obliquus in stands of living birch trees in Finland. The study included 679 living birch trees (Betula pendula and Betula pubescens) across 24 stands. Researchers inoculated these trees with two strains of Inonotus obliquus. They re-examined the inoculated trees after 4-5 years. Upon reexamination, the researchers determined that they successfully infected about 79%(±13%) of the trees per stand with the chaga fungus. About 6%(±15%) of the trees per stand displayed one or more fruiting bodies. Additionally, about 13% of all infected trees showed signs of bulging or cracked bark. This indicates the beginning of fruiting body formation under the bark.
The researchers determined that several conditions influenced the probability of successful inoculation. This included the direction of the inoculation site, soil chemistry, tree diameter, time of inoculation seasonally, size density of the stand, and fungal strain of L. obliquus used.
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