Dietary Index for Gut Microbiota and Risk of Hypertension: The Mediating Role of Homa-Ir in a Five-Year Prospective Cohort Study in Iranian Adults Publisher



Nikparast A ; Maleki M ; Zamanian N ; Sheikhi L ; Etesami E ; Javdan G ; Homayounfar R ; Razaz J M
Source: Nutrition and Metabolism Published:2026

Abstract

Background: Diet–microbiota interactions may influence blood pressure via metabolic pathways, but prospective evidence on microbiota-supportive dietary patterns and incident hypertension, particularly in Middle Eastern populations, is limited. We examined the association between a Dietary Index for Gut Microbiota (DI-GM) and incident hypertension, and assessed whether insulin resistance, measured by homeostatic model assessment for insulin resistance (HOMA-IR), mediates this relationship. Methods: This prospective cohort included 5,185 Iranian adults free of hypertension at baseline. Usual dietary intake was assessed using a validated 125-item food-frequency questionnaire, and a 12-component DI-GM was computed. Incident hypertension over five years was defined according to JNC-7 criteria. Multivariable logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs) for hypertension across DI-GM quartiles and per one-unit increment. Mediation by HOMA-IR was evaluated using bootstrapped mediation analysis with 10,000 resamples. Results: During follow-up, 2,150 participants experienced incident hypertension (41.5%). In fully adjusted models, participants in the highest DI-GM quartile had 21% lower odds of hypertension than those in the lowest quartile (OR 0.79, 95% CI 0.66–0.95), and each one-unit higher DI-GM was associated with 4% lower odds (OR 0.96, 95% CI 0.93–0.99). Results were robust in multiple sensitivity analyses. Approximately 34.5% of the association between DI-GM and hypertension was mediated by HOMA-IR. Conclusions: A microbiota-supportive dietary pattern is prospectively associated with a lower risk of incident hypertension, and about one-third of this relationship appears to operate through reduced insulin resistance. These findings support the promotion of gut-friendly dietary patterns in strategies for hypertension prevention. © The Author(s) 2026.