It is established that the gut microbiota has a significant influence on Alzheimer’s disease. In turn, both the disease and the microbiota are affected by biological variables associated with modern lifestyles. Examination of the potential interrelationship among these three factors and on the role played by lifestyles in gut dysbiosis-induced pathologies of Alzheimer’s disease are limited. Deciphering these connections will provide insights into the pathogenesis and therapeutic strategies for Alzheimer’s disease. Specifically, based on this trilateral relationship, various nonpharmacological interventive strategies targeting the gut microbiota can be developed. This review fills this gap by presenting the latest evidence for the modulative role of modern lifestyle on the gut microbiota and its relevance to Alzheimer’s disease, with a discussion on the limitations of current research and future directions.