Association between dietary index for gut microbiota and diarrhea among US adults: a cross-sectional analysis of NHANES 2005-2010

Abstract

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.

Keywords: NHANES; cross-sectional study; diarrhea; dietary index for gut microbiota; gut microbiota.

Figure 1

Flow chart of the screening of the NHANES 2005–2010 participants. DI-GM, dietary index for gut microbiota.

Figure 2

(A) Association between total DI-GM score and odds ratio (OR) of diarrhea. (B) Association between the beneficial component score and OR of diarrhea. (C) Association between the unfavorable component score and OR of diarrhea. DI-GM, dietary index for gut microbiota; PIR, poverty income ratio; BMI, body mass index; CVD, cardiovascular disease; RCS, restricted cubic spline. The model was adjusted for age, gender, race, marital status, education level, PIR, physical activity, smoking status, alcohol intake, BMI, total calories intake, diabetes, CVD, hypertension, hyperlipidemia, and depression.

Figure 3

Subgroup analyses of the association between DI-GM and diarrhea among participants. DI-GM, dietary index for gut microbiota; PIR, poverty income ratio; BMI, body mass index; CVD, cardiovascular disease; CI, confidence interval; OR, odd ratio. The model was adjusted for age, gender, race, marital status, education level, PIR, physical activity, smoking status, alcohol intake, BMI, total calories intake, diabetes, CVD, hypertension, hyperlipidemia, and depression.