Abstract
Apples are rich in (poly)phenols and dietary fiber and have been associated with reducing the risk of chronic diseases. Emerging evidence suggests that inter-individual variability in metabolic responses to foods may be partly explained by differences in gut microbiota composition. However, whether apple induced metabolic responses differ according to baseline enterotype remains unclear. In this 12-week single-blind intervention trial, we investigated enterotype-stratified associations between daily apple consumption, gut microbiota profiles, and metabolic parameters in Japanese adults aged 40-65 years. Participants were classified into three enterotypes based on family-level gut microbiota composition; Bacteroidaceae (ET1), Ruminococcaceae (ET2) and Prevotellaceae (ET3). Multivariable association analysis using MaAsLin 3 identified five microbial genera associated with obesity and hyperlipidemia status after adjustment for repeated measures and relevant covariates, including Bifidobacterium, Lachnospira, Prevotella, Anaerostipes, and Dialister. While systemic lipid- or glucose-related host parameters did not differ across enterotype, fecal short-chain fatty acid concentrations increased significantly following apple consumption in participants classified as the Bacteroidaceae-dominant enterotype ET1. These findings suggest that baseline gut microbiota structures may modulate specific functional responses to apple intake, highlighting enterotype-dependent heterogeneity in metabolic adaptation.