Across centuries, traditional medicine has turned to fungi not merely as food but as medicine — and now, systematic science is beginning to ask why. A review of twenty edible and medicinal mushroom species finds that their complex carbohydrates survive human digestion and reach the colon intact, where they nourish beneficial bacteria and generate molecules linked to metabolic resilience. The implications touch some of modernity's most persistent ailments — obesity, diabetes, inflammatory bowel disease — yet the path from laboratory promise to human proof remains, for now, unwalked.