ORIGINAL RESEARCH article
Front. Nutr.
Sec. Nutrition and Metabolism
Association of Dietary Phytochemical Index with Sleep Quality, Gut Microbiota, and Inflammatory Markers in Adults with Type 2 Diabetes: A Cross-Sectional Study
Provisionally accepted
- 1The First People's Hospital of Xiangtan City, Xiangtan, China
- 2Xiangxi Autonomous Prefecture People's Hospital, Jishou, China
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Background: Type 2 diabetes mellitus (T2DM) is associated with sleep disturbances, inflammation, and gut dysbiosis, potentially modifiable by diet. This study examined associations between the Dietary Phytochemical Index (DPI), sleep quality, systemic inflammation, and gut microbiota in adults with T2DM, exploring the mediating role of the Firmicutes/Bacteroidetes (F/B) ratio. Methods: In this cross-sectional study, 675 adults with T2DM (aged 35–75 years) were recruited. DPI was calculated from a validated Food Frequency Questionnaire. Objective sleep was assessed via BodyMedia SenseWear armband (duration, efficiency, latency, WASO); subjective sleep via Pittsburgh Sleep Quality Index (PSQI). Inflammatory markers (CRP, IL-6, TNF-α), oxidative stress (MDA, TAC, SOD), hormones (melatonin, cortisol), and gut microbiota (16S rRNA sequencing, F/B ratio, diversity indices) were measured. Linear regression and mediation analyses were performed. Results: Participants in the highest DPI quartile (Q4) had longer sleep duration (422.69 ± 20.01 vs 367.47 ± 43.36 min, p<0.001), shorter sleep latency (11.9 ± 2.47 vs 19.1 ± 7.8 min, p<0.001), lower wake-after-sleep-onset (39.44 ± 4.09 vs 52.3 ± 9.64 min, p<0.001), higher sleep efficiency (90.21 ± 3.14 vs 84.83 ± 6.68 %, p<0.001), and lower PSQI scores (4.49 ± 1.1 vs 6.81 ± 1.5, p<0.001) compared with Q1. Inflammatory markers were lower in Q4: CRP (1.90 ± 0.40 vs 3.60 ± 0.90 mg/L), IL-6 (3.28 ± 0.58 vs 5.07 ± 1.02 pg/mL), and TNF-α (4.71 ± 0.55 vs 6.59 ± 1.13 pg/mL; all p<0.001). DPI was associated with higher gut microbial alpha-diversity and a lower Firmicutes/Bacteroidetes (F/B) ratio. Exploratory statistical analyses suggested that the F/B ratio showed statistical associations with the relationship between DPI and sleep parameters, though causal mediation cannot be established from cross-sectional data. Conclusion: Higher DPI scores is associated with better sleep quality, lower systemic inflammation, and healthier gut microbiota in adults with T2DM. These findings highlight the potential role of phytochemical-rich diets in supporting sleep quality and metabolic health among adults with type 2 diabetes; however, prospective randomized controlled trials are required to confirm these associations and to establish causality.
Keywords: Dietary phytochemical index, Gutmicrobiota, Inflammation, sleep quality, type 2 diabetes mellitus
Received: 12 Dec 2025; Accepted: 11 Feb 2026.
Copyright: © 2026 Li, Li, Yu, Liu, Li, Liu, Yuan and Luo. 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: Qiang Luo
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