The Association Between the Alternate Mediterranean Diet Index and Constipation: Evidence from the 2005-2010 NHANES

Background Diet plays a significant role in the develo1pment of constipation, and the alternate Mediterranean diet index (aMED) serves as an indicator of a healthy dietary pattern. However, the association between aMED and constipation has not been well studied in the general population. The aim of this study was to evaluate the relationship between the aMED and constipation. This study utilized cross-sectional data from individuals aged 20 and above who participated in the 2005–2010 National Health and Nutrition Examination Survey (NHANES). Detailed information was collected regarding constipation, aMED scores and several key covariates. Methods A total of 11397 participants were included in this study. Chronic constipation was defined using the Bristol Stool Form Scale (BSFS) as types 1 (separate hard lumps, like nuts) and 2 (sausage-like, but lumpy). aMED scores were obtained from 48-hour dietary recall questionnaires and categorized into quartiles. The relationship between aMED and constipation was assessed using weighted logistic regression and smoothed curve fitting, adjusting for potential confounders. Stratification by age, BMI, presence of hypertension diabetes, vascular disease and depression was also performed. Results The prevalence of chronic constipation in this cohort was 7.4%. The weighted logistic regression results showed that compared with individuals in the lowest aMED score category (Q1, 3 ≤ aMED < 5) those in the higher quartiles (Q2, 5 ≤ aMED < 5.5; Q3, 5.5 ≤ aMED < 6.5; Q4, 6.5 ≤ aMED ≤ 9) had adjusted ORs for constipation of 0.57 (95% CI: 0.41–0.78, P = 0.002 ), 0.64 (95% CI: 0.48–0.84, P = 0.003 ) and 0.46 (95% CI: 0.33–0.65, P = < 0.001 ), respectively. This indicates that as aMED scores increase the risk of constipation decreases. Individuals in the highest aMED category had a 54% lower risk of constipation compared to those in the lowest category. Further analysis using smoothed curve fitting confirmed a linear negative correlation between the aMED index and constipation.Stratified analyses were conducted based on sex, BMI, diabetes, hypertension, depression, and cardiovascular disease to evaluate potential modifications in the relationship between aMED scores and constipation. The findings demonstrated that the association persisted consistently across all subgroups, with no significant interaction effects detected. Conclusion Our study found that higher adherence to the aMED dietary pattern was significantly associated with a reduced risk of constipation, suggesting that promoting adherence to this diet may serve as an effective strategy for relieving constipation.