ORIGINAL RESEARCH article
Front. Nutr.
Sec. Clinical Nutrition
Volume 12 - 2025 | doi: 10.3389/fnut.2025.1615386
Association of Dietary Index for Gut Microbiota with Frailty in Middle-Aged and Older Americans: A Cross -sectional Study and Mediation Analysis
Provisionally accepted
- 1Faculty of Humanities and Social Sciences, Macau Polytechnic University, Macau, China
- 2Faculty of Applied Sciences, Macao Polytechnic University, Macao, China
- 3Shanghai Maritime University, pudong, China
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Background: While frailty poses significant challenges in aging populations, evidence regarding gut microbiome-targeted nutritional strategies remains limited. The novel Dietary Index for Gut Microbiota (DI-GM), quantifying microbial-pertinent dietary patterns, provides a framework for personalized frailty mitigation. Methods: This cross-sectional study analyzed 12,914 middle-aged and older Americans (≥45 years) from National Health and Nutrition Examination Survey 2005-2018. Frailty status was assessed using a validated 49-item index (non-frail ≤0.21; frail >0.21). The DI-GM (range 0-10) was derived from 14 microbiota-linked dietary components through two 24hour recall interviews. Multivariable logistic regression with sensitivity analyses, restricted cubic splines (RCS), stratified analyses, and mediation effect were implemented to systematically evaluate DI-GM-frailty associations. Results: Adjusted analyses revealed a dose-dependent inverse association between DI-GM and frailty (OR = 0.86, 95%CI: 0.84-0.88 per unit increase). RCS identified a nonlinear inflection at DI-GM = 4.082 (P for nonlinearity = 0.031), beyond which each unit elevation corresponded to 12.6% reduced frailty probability (OR = 0.874, 95%CI: 0.806-0.947). Stratified analyses demonstrated enhanced protective effects in women (OR = 0.84 vs. male 0.90; P for interaction = 0.011) and college-educated individuals (OR = 0.85 vs. 0.93; P for interaction = 0.031). Mediation analysis indicated BMI mediated 38.28% (95%CI: 26.62-62.6, P < 0.001) of the DI-GM effect on frailty progression. Conclusions: Higher DI-GM scores associate with lower frailty prevalence, particularly among women and highly-educated populations, partially mediated through BMI modulation. These findings establish DI-GM as a microbiota-targeted nutritional guideline for age-related frailty interventions, bridging dietary patterns with microbial homeostasis in geriatric care.
Keywords: Frailty, gut microbiome, DI-GM, Nutritional Strategies, mediation effect, Geriatric care
Received: 21 Apr 2025; Accepted: 05 Jun 2025.
Copyright: © 2025 Li, Liu, Shen, Shao and Jiang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Chanzhuan Shao, Shanghai Maritime University, pudong, China
Hongke Jiang, Shanghai Maritime University, pudong, China
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