Plant-Based and Mediterranean Diets Associated With Lower Constipation Risk, Large Cohort Study Finds
Long-term adherence to plant-based and Mediterranean-style diets is associated with a lower risk of developing chronic constipation, according to findings from a pooled analysis of over 95,000 participants across three major U.S. cohorts. The results provide evidence for dietary pattern-based approaches to managing constipation risk, beyond isolated nutrient intake.
The study included participants from the Nurses’ Health Study (NHS), NHSII, and Health Professionals Follow-up Study (HPFS), with over 7,500 incident cases of chronic constipation identified based on symptoms lasting 12 or more weeks per year. Researchers evaluated five dietary patterns using validated food frequency questionnaires and examined their associations with new-onset constipation over 2–4 years of follow-up.
Compared to participants in the lowest quintile of adherence, those in the highest quintile of the alternate Mediterranean diet (aMED) and plant-based dietary index (PDI) had a 16% and 20% lower risk of constipation, respectively. In contrast, the empirical dietary inflammatory pattern (EDIP), Western diet (WD), and low-carbohydrate diet (LCD) were associated with 24%, 22%, and 3% increased risk, respectively.
“These associations were independent of total fiber or ultra-processed food intake,” the authors noted, suggesting the protective effects were linked to overall dietary pattern quality rather than individual components alone.
Vegetable and nut consumption, key components of both the aMED and PDI, were specifically associated with reduced constipation risk.
“Our findings suggest that dietary patterns emphasizing plant-based foods and healthy fats may protect against constipation,” the authors concluded.
For gastroenterologists, these results support recommending dietary interventions that prioritize whole plant-based foods and healthy fat sources in patients at risk for or managing chronic constipation, rather than focusing solely on fiber supplementation.
Reference
Wang Y, Kuo B, Berschback M, Huttenhower C, Chan AT, Staller K. Dietary patterns and incident chronic constipation in three prospective cohorts of middle- and older-aged adults. Gastroenterology. Published online July 2, 2025. doi:10.1053/j.gastro.2025.06.020
