In a simulated human colon, powders made from oat-grown cordyceps (Cordyceps militaris), reishi (Ganoderma lucidum), lion’s mane (Hericium erinaceus) and turkey tail (Trametes versicolor) increased short-chain fatty acids and beneficial bacteria. Because the powders include both mushroom biomass and the underlying oat substrate, the study shows that the combined material is fermentable and supports microbiome activity, though it does not isolate how much of the effect comes from the mushrooms themselves. (Corrected)