Impacts of dietary patterns on the gut microbiome: comparing a priori dietary indices and a posteriori dietary patterns

Abstract

This study examined the associations of a priori dietary indices and a posteriori dietary patterns with gut microbiome diversity and taxonomic composition. Primary stool samples were combined with long-term food purchase data from 142 households collected between 2017 and 2020. A priori indices, including the alternative Mediterranean Diet Score and revised Healthy Purchase Index, were calculated using predefined criteria, while a posteriori patterns were derived using principal component analysis. The revised Healthy Purchase Index and prudent dietary pattern were positively associated with microbial diversity, whereas the alternative Mediterranean Diet Score and overall food consumption intensity were not. At the genus level, the high alternative Mediterranean Diet Score group showed greater abundances of short-chain fatty acid-producing genera, including Anaerostipes, Faecalibacterium, and Roseburia, whereas these differences were not observed for the revised Healthy Purchase Index or prudent dietary pattern. These findings suggest that dietary quality and patterns may contribute to gut microbiome composition.