A Mediterranean Diet Pattern Improves Intestinal Inflammation Concomitant with Reshaping of the Bacteriome in Ulcerative Colitis: A Randomised Controlled Trial

J Crohns Colitis. 2023 Nov 8;17(10):1569-1578. doi: 10.1093/ecco-jcc/jjad073.


Background and aims: Dietary patterns are important in managing ulcerative colitis [UC], given their influence on gut microbiome-host symbiosis and inflammation. We investigated whether the Mediterranean Diet Pattern [MDP] vs the Canadian Habitual Diet Pattern [CHD] would affect disease activity, inflammation, and the gut microbiome in patients with quiescent UC.

Methods: We performed a prospective, randomised, controlled trial in adults [65% female; median age 47 years] with quiescent UC in an outpatient setting from 2017 to 2021. Participants were randomised to an MDP [n = 15] or CHD [n = 13] for 12 weeks. Disease activity [Simple Clinical Colitis Activity Index] and faecal calprotectin [FC] were measured at baseline and week 12. Stool samples were analysed by 16S rRNA gene amplicon sequencing.

Results: The diet was well tolerated by the MDP group. At week 12, 75% [9/12] of participants in the CHD had an FC >100 μg/g, vs 20% [3/15] of participants in the MDP group. The MDP group had higher levels of total faecal short chain fatty acids [SCFAs] [p = 0.01], acetic acid [p = 0.03], and butyric acid [p = 0.03] compared with the CHD. Furthermore, the MDP induced alterations in microbial species associated with a protective role in colitis [Alistipes finegoldii and Flavonifractor plautii], as well as the production of SCFAs [Ruminococcus bromii].

Conclusions: An MDP induces gut microbiome alterations associated with the maintenance of clinical remission and reduced FC in patients with quiescent UC. The data support that the MDP is a sustainable diet pattern that could be recommended as a maintenance diet and adjunctive therapy for UC patients in clinical remission. ClinicalTrials.gov no: NCT0305371.

Keywords: Mediterranean diet; inflammation; microbiome; ulcerative colitis.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Butyric Acid
  • Canada
  • Colitis, Ulcerative* / drug therapy
  • Diet, Mediterranean*
  • Feces / chemistry
  • Female
  • Humans
  • Inflammation
  • Leukocyte L1 Antigen Complex / analysis
  • Male
  • Middle Aged
  • Prospective Studies
  • RNA, Ribosomal, 16S


  • RNA, Ribosomal, 16S
  • Butyric Acid
  • Leukocyte L1 Antigen Complex

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