In adults with mild cognitive impairment eating the MMKD, ↑ Tenericutes and Enterobacteriaceae = ↓ CSF Aβ42, ↑Lachnospiraceae, Rikenellaeae, and Parabacteroides = ↑ CSF Aβ42, and ↑Sutterella and Mollicutes = ↑ and ↓ tau-p181, respectively. The gene discussed is MAPT; the disease is Cognitive impairment.