Mushroom Biology 101

The part of the mushroom you eat, and the part that matters on a lab report, are not the same thing.

A mushroom is the fruit of a much larger organism. Most of it lives out of sight as a fine web of threads called mycelium, spread through wood or soil. What pushes up above the surface is the fruiting body, and it is the part you would recognize in a shop.

This distinction matters when you shop. Many products on the market are grown by feeding mycelium a tray of grain, then grinding up the whole thing, grain included. It is cheaper, and the label can still say the name of the mushroom. What you get is mostly starch.

Beta-glucans are the natural compounds in mushrooms that most of the research looks at. The percentage tells you how much of the extract is the real thing rather than starch or filler.

Beta-glucans sit inside cell walls that are tough enough to survive a trip through the human gut. That is why we extract rather than simply dry and grind. Extraction opens those walls so the compounds are free by the time you stir a spoonful into your cup.