Cranberry and Gut Health in Crohn's Disease

This randomized, double-blind, placebo-controlled clinical trial evaluates the effect of a cranberry dietary supplement-rich in polyphenols and fermentable fiber-on the gut microbiome, inflammation, and health-related quality of life in adults with Crohn's disease (CD). Crohn's disease is a chronic inflammatory bowel disease associated with significant dysbiosis (disruption of the gut microbial community), and patients often experience impaired quality of life despite medical treatment. There is growing interest in food-based strategies that may favorably impact the gut microbiota in individuals with CD. Polyphenols and fermentable fibers found in whole plant foods-especially in cranberries-have demonstrated prebiotic-like effects in preclinical and small-scale human studies.

The primary aim of this study is to determine whether daily consumption of a freeze-dried, 100% cranberry powder supplement for 10 weeks improves the gut microbiome composition. Secondary objectives include assessing changes in inflammation, gastrointestinal symptoms, and quality of life, as well as evaluating the persistence of any microbiome shifts during the follow-up period after supplement cessation.

Participants are randomized 1:1 to either the intervention group (cranberry) or a control group (placebo; matched in appearance and flavor) and will consume the assigned supplement daily for 10 consecutive weeks. The total study period for each participant is 15 weeks, which includes a 10-week intervention and a 4-week follow-up phase. Participants will be blinded to group assignment, and supplements will be pre-packaged and labeled to maintain allocation concealment.

Throughout the study, participants complete questionnaires and collect biological samples at four time points: baseline (week 0), midpoint (week 6), end of intervention (week 10), and follow-up (week 14). Study assessments include the short Crohn's Disease Activity Index (sCDAI), the short Inflammatory Bowel Disease Questionnaire (sIBDQ), and dietary evaluations. These tools are used to assess changes in disease activity, gastrointestinal symptoms, health-related quality of life, and habitual diet. Participants also report any adverse events or changes in medications daily throughout the study.

Biological samples collected include stool, urine, and capillary blood (via the Tasso™ device), obtained at each time point using home collection kits. Stool samples are used for 16S rRNA sequencing and metagenomic analysis to characterize microbiome composition and function. Urine and blood are analyzed for markers f cranberry intake. Sample return is facilitated by pre-labeled, insulated packaging with cold packs. Participants receive training materials, including video instructions and support from the study team as needed.

Inclusion criteria

• Adult CD patients between 18 and 65 years old.
• Women of childbearing potential will be required to use at least one form of "highly effective" contraception throughout the study.
• Confirmed diagnosis of Crohn's disease.
• CD activity lower than sCDAI<450.
• Moderate to severely impaired Health Related Quality of life (HRQoL). sIBDQ score <60.
• Stable dose of medications at screening; thiopurines, natalizumab, methotrexate (12 weeks), anti-TNF, ustekinumab (8 weeks), vedolizumab (8 weeks), 5-ASA (2 weeks),
• steroids (1 week).
• Willingness and capacity to significantly consume the cranberry supplement daily.
• Willing and able to comply with specimen collection and other study procedures, and to complete the study.
• Able to provide written informed consent.
• Reside in Massachusetts, USA.

Exclusion criteria

• Ostomy
• Presence of symptomatic or significant stricture or history of obstruction in the past 6 months
• Pregnancy
• Use of Specific Carbohydrate Diet of IBD- AID within 4 weeks of screening
• Use of probiotics within 4 weeks of screening
• Use of antibiotics within 4 weeks of screening
• > 20mg prednisone or equivalent
• Recent C. difficile colitis
• Unable to provide informed consent for themselves
• Prisoners
• Children