The gut-brain axis, a bidirectional communication network between the gastrointestinal tract and the central nervous system, regulates various physiological processes crucial for health, including immune response, metabolism, and neurotransmitter production. In the context of neurodegenerative diseases, especially Alzheimer's disease (AD), understanding the intricate connection of the gut-brain axis has gained significance. Disturbances along this axis have been implicated in neurodegenerative diseases, emphasizing its role in AD pathogenesis. Microbiota dysbiosis, influenced by diet, lifestyle, and genetics, contributes to altered gut permeability, leading to protein dyshomeostasis, astroglial activation, neuroinflammation, and cognitive decline. Understanding these mechanisms is crucial for developing interventions to restore a healthy gut microbiota and potentially mitigate AD-related cognitive decline. The bidirectional communication along the gut-brain axis involves microbial metabolites, influencing oxidative stress, protein aggregation, and other pathways linked to neuroprotection. Modulating the gut microbiota through dietary changes, prebiotics, probiotics, or fecal microbiota transplantation emerges as a promising approach to target cognitive decline in AD. Despite progress, challenges persist, including the correlational nature of studies, the complexity of the gut microbiome, and variations in methodologies. Standardization is essential for reliable findings and the identification of biomarkers associated with AD. Unanswered questions warrant further exploration, particularly in understanding specific mechanisms, the temporal dynamics of microbiota changes, and the influence of diet and lifestyle on the gut-brain axis in AD. Future perspectives involve promising therapeutic interventions targeting the gut-brain axis, emphasizing personalized medicine to optimize outcomes based on individual variations in the gut-brain axis characteristics.