Patients with mild-to-moderate Crohn’s disease (CD) who received the Crohn’s Disease Therapeutic Dietary Intervention (CD-TDI) demonstrate clinical, inflammatory, and barrier improvements, as well as more than threefold greater response than those who received conventional management, reports a study presented at DDW 2026.
Apart from these improvements, the CD-TDI also enriched short-chain fatty acid-producing, fibre-, and polyphenol-responsive taxa and reduced mucin-foraging signatures, according to lead study author Dr Natasha Haskey, Department of Biology, University of British Columbia-Okanagan Campus, Kelowna, British Columbia, Canada.
“The CD-TDI is a mechanistically informed whole-food diet emphasizing polyphenols, β-carotene, soluble fibre, resistant starch, and flavanols, nutrients known to balance inflammation, epithelial repair, and gut barrier function,” Haskey said.
“Clinical benefits are accompanied by a coordinated shift in diet quality and inflammatory potential and are underpinned by a functionally optimized microbiome,” she added.
Haskey and her team conducted a 13-week, multicentre, randomized controlled trial to assess the effectiveness of the CD-TDI in inducing clinical and biomarker response among adults with active CD on stable medical therapy for ≥4 weeks. They block-randomized 66 participants by sex (2:1 allocation) either to the CD-TDI (n=42) or to conventional management (n=24).
Of the participants (median age 49 years, median BMI 29 kg/m2), 52 percent were female, and 34 percent had been previously exposed to advanced therapies.
Clinical response, the primary outcome, was defined as >2-point improvement in the Harvey‒Bradshaw Index (HBI) and a ≥100-µg/g reduction decrease in fecal calprotectin. Other outcomes assessed included intestinal permeability markers (ie, lipopolysaccharide-binding protein [LBP] and zonulin) and changes in the gut microbiome.
Clinical improvements
The CD-TDI group demonstrated a significant decrease in HBI, from 3 to 1 (p=0.03), while those in the conventional management group showed no improvement. Reductions were also seen in zonulin (from 259 to 145 ng/mL; p=0.001) and LBP (from 20 to 17 µg/mL; p=0.04), with LBP being lower in the CD-TDI than the conventional management group at week 13 (p=0.01). [DDW 2026, poster Mo1783]
A significantly greater proportion of participants in the CD-TDI than the conventional management group showed a clinical response (31 percent vs 12 percent; p=0.02). Among those with active symptoms at baseline (HBI >5), 82 percent of patients assigned to CD-TDI achieved clinical remission compared with 50 percent of those assigned to conventional management.
In microbiome analysis, CD-TDI resulted in increases in Bifidobacterium longum, Roseburia hominis, Sellimonas intestinalis, and several Blautia/Lachnospiraceae taxa, with decreased Clostridium_Q species.
Modest functional pathway changes were also observed, favouring aromatic compound degradation, nucleotide metabolism, and reductions in mucin/fucose/sialic acid utilization in patients who received the CD-TDI.
“A CD-TDI-responsive microbial and functional signature distinguishes responders from non-responders,” Haskay said.
“Together, these findings position diet not just as supportive care [but as] a biologically active, precision nutrition therapeutic [strategy in mild-to-moderate CD],” she added.
“Recognition of diet as a modifiable factor in the management of CD continues to grow. Whole-food diet strategies are appealing because they emphasize nutrient-dense, anti-inflammatory foods while limiting ultra-processed foods that may impair epithelial integrity and microbial homeostasis,” Haskey said.