Chaga Yaga

Botany: what is really harvested

Inonotus obliquus (botanical synonym Polyporus obliquus), also called the birch mushroom and known in Russia as chaga (чага), is a fungus of the Hymenochaetaceae family, a parasite of birches (Betula spp.), more rarely of alder or beech. A detail often overlooked: the black, charcoal-like conk that bursts through the bark — the one that is harvested and called “chaga” — is not the sexual fruiting body of the fungus. It is a sterile mycelial mass, a hard aggregate close to compacted charcoal, which can weigh several kilos. The true fruiting body only forms after the death of the host tree, beneath the bark, and is rarely observed. All the material used therefore comes from the parasitic conk — the visible expression of a long settling into the wounded tree.

Descriptive phytochemistry

Chaga is one of the most studied fungi in modern pharmacology; the literature attributes to it a great number of activities described in vitro. Its compounds fall into two families, and this is what explains the need for double extraction:

• —Water-soluble polysaccharides — beta-1,3-D-glucans and beta-1,6-D-glucans (on the order of 8.5% of dry weight according to reviews), soluble in water.
• —Fat-soluble lanostane-type triterpenoids — inotodiol, betulinic acid, betulinin, lupeol, ergosterol — part of which (betulin and betulinic acid) is inherited from the host birch. Soluble in alcohol only.
• —Melanin and polyphenols: melanin, responsible for the black colour of the conk, is among the densest antioxidant pigments known.

Chaga's antioxidant capacity, measured by the ORAC index, is reported among the highest of all foods studied (an order of magnitude far above that of common berries). This value describes a free-radical-neutralising power measured in the laboratory; it does not in itself constitute a promise of an effect on the human body.

Mechanisms: what the studies report

The available work is largely on cellular or animal models, and must be read with caution: it describes leads, not therapeutic effects established in humans. In vitro studies report an activation of macrophages and NK (Natural Killer) cells by beta-glucans, an antioxidant and anti-inflammatory activity (via inhibition of NF-κB), and, for certain isolated triterpenes such as inotodiol and betulinic acid, an induction of apoptosis in various tumour cell lines in culture. Others report hepatoprotective, antiviral (HSV, HIV, HBV in the test tube) or blood-sugar-lowering effects in animals. None of this translates, to date, into validated medical use: Chaga remains a traditional medicine and a food.

A long history, from the 12th century to today

The oldest documented use goes back to the Khanty of western Siberia, in the 12th century: the conk set to burn slowly then plunged into hot water for a decoction, digestive brews, smoke for the lungs. Russian tradition attaches to Chaga a tenacious reputation as a remedy: it is told — a semi-legendary account — that Tsar Vladimir Monomakh (12th century) was relieved of an ailment of the lip by a Chaga decoction. In the 20th century, the Soviet Pharmacopoeia of 1955 listed Chaga under the name Befunginum, as an official adjuvant — one of the rare bodies of traditional knowledge integrated into a state pharmacopoeia. Then, in 1968, Aleksandr Solzhenitsyn's novel Cancer Ward, in which a character hopes for a “peasant remedy” made from Chaga, made the fungus known outside Russia: after its translation, exports to Europe, Japan and North America soared, and more than 1,600 scientific articles have since been devoted to it. This is the cultural history of a plant — the way a people, a pharmacopoeia and then a novel carried a body of knowledge from one end of the world to the other.

Preparing the complete medicine

The complete traditional path combines two gestures. The long decoction in water (a gentle simmer, never a rolling boil, which alters the polysaccharides) extracts the beta-glucans; it readily runs two to three hours for whole pieces, and the conk can be reused several times. The alcoholic tincture (a maceration of several weeks in alcohol at 40-50%) extracts, for its part, the fat-soluble triterpenes inaccessible to water. Combining the two extracts gives the full spectrum — this is the principle of double extraction, and what the ready-to-use 8:1 extract reproduces. A Chaga powder simply infused stays pleasant and nourishing, but delivers only the water-soluble part.

Safety and ecology

Chaga is generally well tolerated in food use, but its richness in oxalates calls for caution in case of a history of kidney stones; its immunomodulating activity and its reported effects on blood sugar and coagulation warrant medical advice for the people concerned (autoimmune diseases, treated diabetes, anticoagulants, upcoming surgery, pregnancy, breastfeeding). Finally, an ecological truth: Chaga grows slowly, sometimes over ten to twenty years, and the “superfood” craze has caused a worrying over-harvesting in the Russian and North American boreal forests, which the Indigenous communities of Canada report. Hence the need for a measured wild harvest, respectful of the tree's rhythm — the only way not to exhaust the source one celebrates.