Gastrointestinal Changes and Alzheimer's Disease

Background: There is a well-described mechanism of communication between the brain and gastrointestinal system in which both organs influence the function of the other. This bi-directional communication suggests that disease in either organ may affect function in the other. Objective: To assess whether the evidence supports gastrointestinal system inflammatory or degenerative pathophysiology as a characteristic of Alzheimer's disease (AD). Methods: A review of both rodent and human studies implicating gastrointestinal changes in AD was performed. Results: Numerous studies indicate that AD changes are not unique to the brain but also occur at various levels of the gastrointestinal tract involving both immune and neuronal changes. In addition, it appears that numerous conditions and diseases affecting regions of the tract may communicate to the brain to influence disease. Conclusion: Gastrointestinal changes represent an overlooked aspect of AD, representing a more system influence of this disease.