Abstract
Introduction: The prevalence of neurodegenerative diseases and dementia, such as Alzheimer's disease (AD), is increasing. However, the currently available symptomatic and disease-modifying therapies have shown limited benefits for neurodegenerative diseases in clinical settings. Objective: It was to carry out a systematic review to externalize and discuss the main findings on the effects of enteral nutritional therapy, as well as on the action of the intestinal microbiota in patients with brain injuries or neurodegenerative diseases. Methods: The PRISMA Platform systematic review rules were followed. The search was carried out from May to June 2026 in the Web of Science, Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 122 articles were found, and 31 articles were evaluated in full, and 28 were included and developed in the present systematic review study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 25 studies with a high risk of bias and 21 studies that did not meet GRADE and AMSTAR-2. Most studies showed homogeneity in their results, with X2=71.9%>50%. It was concluded that probiotic-supplemented enteral nutrition effectively reduces the risk of mortality, gastrointestinal complications, and infection, and shortens ICU length of stay; therefore, it should be widely adopted for the management of these patients. Nasal inspiratory pressure during a sniff at baseline is an early indicator of disease progression and, consequently, of the need for enteral nutrition in amyotrophic lateral sclerosis. Furthermore, issues regarding tolerance, diarrhea, and abdominal distension decreased between the 3- and 6-month follow-ups in patients receiving home enteral nutrition.