This term used to refer to a mushroom extract containing the full spectrum of therapeutically interesting bioactives in a bioavailable form. Only extracts that have been extracted using both hot water and alcohol extraction (or fermentation) can claim this. These products contain both the water-soluble and the non water-soluble bioactives; in other words, everything that is therapeutically interesting. (During the extraction process only chitin is removed. Chitin is the reason non-extracted mushroom products are indigestible: it locks the bioactives in the cell walls of the mushroom, like a LEGO brick is locked in a LEGO wall.)
However, in the past year we’ve seen several websites where the term ‘full-spectrum’ was used to deceivingly describe a product that was e.g. a combination of mycelia, substrate and fruiting body. A smart play with words, but misleading.
Most medicinal mushrooms were found to have the biggest concentration of bioactives in either the fruiting body or the mycelia, so for most products combining these has no added benefit, although it does indeed sound very ‘complete’ to an ignorant layman. It is just marketing talk. Below we give some examples, to illustrate our point.
Natural Cordyceps. The black 'branch' on the left is the fruiting body, and the caterpillar is filled with mycelia - only the skin is left.
E.g. Cordyceps sinensis fruiting bodies do not contain the marker compounds that are responsible for Cordyceps’ reputation, the nucleosides and the cordycepin. The ancient Chinese already knew this: wild Cordyceps with the highest value is the one with a very small fruiting body and a large ‘worm’ (which is filled with mycelia). Cultivated mycelia of specific strains, chosen for their consistent quality, give the best yield of bioactives.
Reishi, on the other hand is exactly the opposite: Reishi’s marker compounds (the ganoderic acids and other triterpenes) only start developing when the mycelia are about to form a fruiting body (once a year) and are mainly found in the fruiting body.
In old times Reishi’s therapeutic quality was valued by its bitterness. The mycelia are not bitter at all because they contain very little triterpenes. The triterpenes are responsible for the bitter taste.
There are also ‘full-spectrum’ Chaga products for sale that claim to contain a mix of the wild-harvested fruiting body and cultivated (lab-grown) mycelia. This is wrong in more than one way. Chaga is a parasitic fungus, infecting mainly birch trees. Chaga extracts are always mycelia based, because the black growth called Chaga is actually not a fruiting body but a dense, hardened mass of mycelia that comes bursting from the inside of the tree, a few years after infection. It is called a sclerotium.
This is Chaga mycelium cultivated in a petri dish. Small fruiting bodies are forming.
Several of Chaga’s main bioactive ingredients are developing only because of the battle of the fungus with its host; in particular the phyto-sterols and the polyphenols, responsible for the anti-oxidant properties. Lab-grown Chaga mycelia have therefore a completely different chemical composition. Betulinic acid is also absent in lab-grown Chaga mycelia, because in nature the fungus absorbs this from its host, the birch tree. Therefore only dual extracted, wild-harvested Chaga can claim to contain the full spectrum of bioactives.
Apart from all this a key point remains the extraction procedure. No matter what the source or composition is of a particular mushroom product, if it has not been extracted it is best avoided. It should also have a specification of the main bioactive ingredients on the supplement facts label, as said before. If not, you have in fact no clue what you actually get and whether or not it will be therapeutically effective, as explained before. The proof of quality lies in the scientific facts, not in folk stories.
Summarising: A full-spectrum mushroom extract should contain the full spectrum of bioactives; meaning both the water soluble and the non-water soluble ones. ‘Full-spectrum’ as a term should refer to a dual extract (hot water + alcohol), not to a product containing the full range of a mushrooms growth cycle.