CHAGA CLAIMS NOT BACKED BY SOLID EVIDENCE
Folk remedy being touted by marketers of pills and extracts as ‘Nature’s Silver Bullet’
If you wanted to find some “Chaga,” you would tromp through a forest looking for a birch tree with an unusual growth on its trunk. Although it is classified as a mushroom, Chaga doesn’t look like one. Instead of having gills, this mushroom is permeated with numerous pores. Under pressure it crumbles readily, revealing a brownish inside with cream coloured veins.
Why would anyone seek out such an ugly parasite that grows from a wound on the bark of a birch tree? Probably because of stories that circulate about the mushroom being prized by natives of northern Asia, Europe and America for its medicinal powers. Folklore speaks of Chaga mushrooms treating virtually every known ailment, ranging from intestinal worms and heart disease to diabetes and cancer.
They have been alluringly referred to as “Nature’s Silver Bullet” and “A Gift from God.” Largely ignored by the Western world for hundreds of years, the tale continues, Chaga is now being recognized for its energyboosting, immune-systemimproving, stress-reducing, detoxifying and anti-cancer properties.
And where are these revelations to be found? Mostly on websites that sell an array of Chaga pills and extracts.
The marketing of Chaga follows a popular formula. An obscure natural substance that virtually nobody has heard about is touted as a non-toxic answer to our health problems. On what basis? There are the usual personal testimonials, there’s reference to historical use as well as to studies that have shown some sort of biological activity in some sort of laboratory or rodent study. Of course, many mushrooms contain compounds that have biological activity, not necessarily desirable.
Amanita muscaria, for example, is highly toxic and psilocybe mushrooms can cause hallucinations. But it certainly is possible that some fungi contain pharmacologically useful compounds. It may even be that Chaga does. But before swallowing the idea that swallowing Chaga pills or extracts or teas is a good thing to do, we had better look at the evidence.
Anecdotes about arthritis improving after drinking Chaga tea, or eczema resolving, or sleep improving, or blood pressure dropping, do not amount to scientific evidence. So what kind of scientific evidence exists? One study that is commonly quoted reported the effect of a Chaga mushroom extract on human white blood cells exposed to the oxidizing agent hydrogen peroxide in the laboratory. The cells treated with the extract showed a 40 per cent reduction in DNA damage. This is often described as “promising anti-cancer activity.” That’s a big stretch.
The reduction in DNA damage is an interesting observation, but is essentially meaningless. Such effects can be seen with virtually any fruit or vegetable extract that contains antioxidants. It doesn’t translate to anything meaningful in terms of ingestion of any Chaga preparation.
Laboratory studies have also shown that Chaga, like any other plant material, contains an array of triterpenes, sterols, beta glucans, flavonoids, melanins, polyphenols, saponins, amino acids, vitamins, minerals and fibre. In some context, all of these have biological activity and with clever writing and selective reporting can be made to look like miraculous ingredients. For example, one bit of supporting evidence offered for the use of Chaga extracts is that during an influenza epidemic a century ago, while the white population was dropping like flies, physicians noted that the Native American population was virtually unaffected. “After close inspection, these physicians attributed the herbs that the Indians were ingesting to their heightened immunity.” First, there is no evidence that Indigenous people were specially protected, and even if they were, it cannot be concluded that it was because of any natural products they were taking, and there is certainly no evidence that they were indulging in any Chaga.
The bottom line is that there is no compelling evidence that ingesting any form of Chaga is beneficial. There are no placebocontrolled randomized trials of Chaga pills or extracts.
Pills are available, but as with any such product, there is no standardization, there is no way to tell what the pills really contain. As far as Chaga teas go, there are numerous recipes that undoubtedly result in different compositions of the final product. It is certainly possible that future research will show that some standardized preparation of Chaga, or a specific dose of a compound found in Chaga, has a therapeutic effect. But so far nothing like that has been shown.
The only truly documented evidence I’ve been able to come up with refers to the combustibility of the fungus. Chaga is sometimes justifiably referred to as a “tinder fungus” because its porous nature gives it a very large surface area and makes it very easy to light. It seems to be just the right substance with which to start a fire. A useful thing to know for people interested in wilderness survival. Unfortunately, its use in disease survival is a different matter. joe.schwarcz@mcgill.ca
Joe Schwarcz is director of McGill University’s Office for Science & Society (mcgill.ca/oss). He hosts The Dr. Joe Show on CJAD Radio 800 AM every Sunday from 3 to 4 p.m.