Microbiota intestinal, disbiose, nutrição e doença de Alzheimer: existe alguma relação?

Abstract

The human intestinal microbiota (IM) consists in a group of microorganisms that live in the digestive tract, in a symbiotic relationship with the host. There is a gut-brain-axis, a bidirectional neuro-humoral communication system, that integrates the host gut and brain activities. IM imbalance (dysbiosis) can increase the permeability of the intestinal barrier and it affects the communication routes of this axis. Dysfunctions in the microbiota-gut-brain axis have been associated with diseases of the nervous system, such as Alzheimer's disease (AD) and other neurodegenerative diseases associated with aging. AD is characterized clinically by a progressive and gradual decrease in cognitive function and neuropathologically by the presence of extracellular plaque deposits of the β-amyloid peptide (Aβ) and the neurofibrillary tangles of the protein tau. Studies with animal models and human indicate that balanced diet can provide benefits, restoring intestinal eubiosis. These findings provide evidence of potentially viable compounds and nutrients for the prevention and treatment of AD. The purpose of this literature review is to summarize and discuss the current findings that may elucidate the role of diet in IM, the relationship with the gut-brain axis and cognitive functions. The understanding of these mechanisms can encourage the adoption of preventive and therapeutic strategies for AD.