Association between Dietary Index for Gut Microbiota and Diarrhea among US Adults: A Cross-Sectional Analysis of NHANES 2005-2010

Xiaoqiang Liu ¹ Xiaobo Liu ² Yingxuan Huang ¹ Lin Chanchan ¹ Xinqi Chen ¹ Yingyi Li ¹ Yisen Huang ^1* Yubin Wang ^1*

• ¹ Quanzhou First Hospital, Fujian Medical University, Quanzhou, China
• ² McGill University, Montreal, Quebec, Canada

Objectives: Growing attention has been paid to the relationship between the gut microbiota and diarrhea. A recently proposed Dietary Index for Gut Microbiota (DI-GM) reflects the overall dietary quality as it pertains to gut microbiota diversity. However, evidence regarding the association between DI-GM and diarrhea is still lacking. This study aims to investigate the association between DI-GM and the risk of diarrhea. Methods: A total of 15,590 adults (≥20 years old) from National Health and Nutrition Examination Survey (NHANES) 2005-2010 were included in this analysis. Diarrhea was defined by self-reported common Bristol Stool Form Scale (BSFS) type 6 or 7, or more than three bowel movements per day. DI-GM comprises 14 food/nutrient components known to be associated with gut microbiota. A higher score indicates a more favorable diet for the gut microbiota. Multivariable logistic regression was used to evaluate the association between DI-GM and diarrhea, with subgroup and sensitivity analyses performed to confirm robustness. Results: After adjusting for age, gender, race, physical activity, chronic diseases, and other confounders, each 1-point increase in DI-GM was associated with a 5% reduction in diarrhea risk (adjusted OR = 0.95, 95% CI: 0.91-0.98, P = 0.005).Compared with those who had a DI-GM score of 0-3, individuals with a DI-GM score ≥6 demonstrated a significantly lower risk of diarrhea (OR = 0.77, 95% CI: 0.65-0.91, P = 0.002). Subgroup and sensitivity analyses further supported this negative association. Notably, the "beneficial component" was found to have a more pronounced effect on reducing diarrhea risk. Conclusion: Based on a large representative population, our findings suggest that a higher DI-GM score is significantly associated with a lower risk of diarrhea, underscoring the importance of overall dietary patterns in maintaining gut function and homeostasis.