Diet and behavioral and psychological symptoms of dementia in the context of the microbiota-gut-brain axis - a scoping review identifying research gap

Abstract Behavioral and Psychological Symptoms of Dementia (BPSD) affect most patients with dementia. Nutritional intervention, as part of non-pharmacological approach to BPSD, has not been adequately investigated. Aim To check, based on published reports, whether nutritional ingredients or specific dietary patterns affect BPSD, and to identify research gaps that could reveal potential new, nutrition-related therapeutic pathways. A secondary aim is to examine dietary changes in patients with different BPSD. Methods We did a scoping review of English-language studies published between 2000 and 2025 and indexed in Pub-Med, Embase, Web of Science and Cochrane Library including adult patients with dementia and BPSD together with information about nutrition. A broad literature search strategy was applied to capture comprehensive range of publications and identify research directions. Results Of 405 identified records, 63 manuscripts were identified; 3 full-text original articles were included for primary and secondary objective: a study demonstrated effect of apple juice consumption on reduction of NPI score in BPSD and two studies indicated relation between behavioral symptoms and dietary habits. Other studies highlighted the potential role of gut microbiota in serotonin production and the potential favorable effects of tryptophan-rich diets. A single paper directly examined the relationship between diet, gut microbiota, and BPSD, and outlined plans for further research. Overall, study methodologies of identified manuscripts and measurements of BPSD were heterogeneous. No studies directly examined a broader effect of diet on BPSD. Conclusion More studies are needed to examine the role of diet, and gut microbiota, in the management of BPSD.