DOP040 Plant-based diets mitigate incidence, disease course and comorbidity of inflammatory bowel disease: evidence across eight European countries
Authors: Chen J , Sun Y , Dan L , Wellens J , Yuan S , Yang H , Tong T , Cross A , Papadimitriou N , Antoine M , Dahm C , Larsson S , Wolk A , Ludvigsson J , Tsilidis K , Giovannucci E , Satsangi J , Wang X , Theodoratou E , Chan S , Li X ,   Collaborators-EPIC investigators: Pilar Amiano Marie-Christine Boutron-Ruault Marcela Guevara Marc J Gunter Mazda Jenab Rudolf Kaaks Tim J Key María Dolores Chirlaque López Giovanna Masala Bas Oldenburg Anja Olsen Elio Riboli Carlotta Sacerdote Matthias Schulze Gianluca Severi Anne Tjønneland Ruth C Travis Rosario Tumino Roel Vermeulen W. M. Monique Verschuren Nick Wareham
Published: January 2025

Abstract

Background
Many currently proposed diets for inflammatory bowel disease (IBD) focus on increasing plant-based foods, although a vegetarian diet can still contain products such as emulsifiers and refined grains that negatively impact IBD incidence and progression. To better inform dietary management in IBD, we investigated the association between different plant-based diets and the incidence and disease course of IBD.

Methods
We leveraged data from the UK Biobank (UKB) including 187,888 participants free of IBD at baseline and the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort including 341,539 individuals free of IBD, spanning eight European countries (Figure 1). Plant-based diet indexes (healthy and unhealthy PDI) were constructed based on the 24-h dietary recalls. The primary outcome was incidence of IBD, including Crohn’s disease (CD) and ulcerative colitis (UC), and the secondary outcome was the disease course. Cox regression was applied to estimate hazard ratios (HRs), and interactions between genetics and plant-based diets were explored.

Results
In the UKB (925 incident IBD, median follow-up 11.6 years), higher adherence to healthy PDI was associated with a lower IBD risk (HR 0·75, 95% CI 0·60-0·94), while higher alignment to an unhealthy PDI associated with an increased risk (HR 1·48, 95% CI 1·21-1·82) when comparing extreme quintiles of PDIs (Figure 2). Findings were consistent in the association between healthy and unhealthy PDIs and the risk of CD and UC. For the disease course and comorbidities, both a healthy PDI (HR 0·50, 95% CI 0·30-0·83) and unhealthy PDI (HR 2·12, 95% CI 1·30-3·44) were linked to related surgery among individuals with IBD, while the associations were not significant in other prognostic outcomes including cardiovascular disease, diabetes mellitus, and all-cause mortality. In the EPIC study (548 incident IBD, median follow-up 14·5 years), the HRs of incident IBD for healthy PDI (HR 0·71, 95% CI 0·59-0·85) and unhealthy PDI (HR 1·54, 95% CI 1·30-1·84) validate the results in UKB. Mediation analysis showed the associations of healthy and unhealthy PDIs were mediated by inflammation status and may be greater for participants with moderate or high genetic risk to develop IBD.

Conclusion
Our findings highlight the protective effect of healthy plant-based diets on IBD incidence and progression, while an adverse association was found for an unhealthy plant-based diet. Adherence to a healthy PDI might be a strategy to improve the natural history of IBD, especially in those with moderate or high genetic risk. These findings support that plant-based foods should be recommended yet underline the possible need for specialised dietetic counselling to ensure the overall quality of diet.