On The Shelf
Johanna Taylor Katroscik, PharmD
As public interest in dietary and food supplements continues to rise, so does interest in the potential health benefits mushrooms may offer. “There Is a Lot of Fungus Among Us,” a New York Times article published in 2021, looked at how different mushrooms are making their way into the mainstream wellness market. Teas, tinctures, and whole mushrooms are being studied for different medicinal properties. Some mushrooms such as shiitake, reishi, or lion’s mane may be well-known, while other mushrooms, like chaga, are not. Chaga is a mushroom that can be used alone or combined with other mushrooms in teas or supplements and is just starting to become more popular.
Background and function
Chaga (Inonotus obliquus) is a mushroom that has been used as a traditional medicine for centuries by different cultures across the globe in Eastern Europe, Asia, Russia, Canada, and the northern United States. It grows on birch trees in boreal forests and is only found in the northern hemisphere.
Although it is considered a parasite, it forms a symbiotic relationship with the trees it grows on, protecting injured or damaged bark from external pathogens. It is a slow-growing fungus and will often grow with a tree for years. Chaga does not look like a typical mushroom—it most often looks like a burned or damaged part of a tree and has a firm, bark-like texture.
Chaga is often used as a supplement to help boost the immune system or reduce inflammation. It has also been used to help fight cancer, lower blood sugar, and to help reduce cholesterol.
Is there a benefit?
To date, there have been no in vivo clinical trials that have looked at the potential benefits or harms of chaga in people. However, there have been numerous animal and in vitro studies that have looked at the effects of chaga on cancer cells, immune cells, and normal cells. Several of these studies suggest that chaga has antiproliferative effects on a variety of different types of cancer and tumor cells.
Even more interesting is that in vitro studies show evidence that while chaga slows or stops growth of harmful cells, it seems to have little to no effect on “normal” cells and their function. This initial data suggest that chaga may be beneficial to health. However, more conclusive evidence is needed to be able to say this with certainty.
Daily requirements and dietary sources
There is currently no recommended daily requirement for chaga. In general, there are no dosage recommendations and using chaga as a dietary supplement has few to no adverse effects on healthy individuals.
Chaga is commercially available as whole dried pieces of the mushroom, dried powder, capsules, tinctures, and tea. The dosage form people choose is generally based on personal preference. Additionally, many people forage for or harvest their own chaga. It is not recommended to forage for chaga unless you have experience and know exactly what it looks like—mushrooms that are misidentified can be deadly.
What to tell your patients
Chaga is, in general, well-tolerated and safe to use. As noted above, foraging or harvesting one’s own chaga is not recommended if the person has no experience with foraging. Patients who are interested in trying chaga as a supplement should be counseled on the different options available (i.e., tea, capsule) and should look for brands or manufacturers that have used a third-party certifier (e.g., USP, UL, NSF International).
As always, it should be noted that supplements are not FDA-approved or regulated and cannot make claims to cure or treat diseases or ailments. Because of certain chemical components of chaga, it should be avoided by people with kidney issues, osteoporosis, people who are taking blood thinners, people who are taking medication to help control their diabetes, people who have an autoimmune disease, and people who are pregnant. ■