This chapter argues that lion’s mane (Hericium erinaceus), reishi (Ganoderma lucidum), and cordyceps (Cordyceps militaris) may offer low-risk, early nutritional support for cognitive decline by reducing brain inflammation, protecting mitochondria, and promoting nerve growth. It highlights emerging human evidence showing benefits for mild cognitive impairment, alongside strong preclinical data on neurogenesis and antioxidant activity. Framed as complementary—not curative—these mushrooms are presented as promising early interventions that could fit into holistic, preventive dementia care while the field awaits larger clinical trials.