Diet, Food, and Nutritional Exposures and Inflammatory Bowel Disease or Progression of Disease: an Umbrella Review

Abstract

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), contributes to substantial morbidity. Understanding the intricate interplay between dietary factors and the incidence and progression of IBD is essential for developing effective preventative and therapeutic strategies. This umbrella review comprehensively synthesizes evidence from systematic reviews and meta-analyses to evaluate these complex associations. Dietary factors associated with an increased incidence and/or progression of IBD include a high intake of red and processed meat, other processed foods, and refined sugars, together with a low intake of vegetables, fruits, and fiber. For most other food groups, the results are mixed or indicate no clear associations with IBD, CD, and UC. Some differences seem to exist between UC and CD and their risk factors, with increased intake of dietary fiber being inversely associated with CD incidence but not clearly associated with UC. Dietary fiber may contribute to maintaining the gut epithelial barrier and reduce inflammation, often through interactions with the gut microbiota. This seems to play an important role in inflammatory mechanisms in the gut and in IBD incidence and progression. Diets low in fermentable saccharides and polyols can alleviate symptom burden, but there are concerns regarding their impact on the gut microbiota and their nutritional adequacy. Mediterranean diets, vegetarian diets, and a diet low in grains, sugars, and lactose (specific carbohydrate diet) are also associated with lower incidence and/or progression of IBD. The associations of dietary patterns are mirrored by inflammatory biomarkers. IBD is typically treated pharmaceutically; however, many patients have a suboptimal response to medical treatments. The findings from this umbrella review could provide evidence for nutritional counseling and be a valuable addition to traditional treatment plans for IBD. This systematic review was registered at PROSPERO as CRD440252.

Keywords: Crohn’s disease; dietary patterns; food groups; inflammatory bowel disease; ulcerative colitis.

FIGURE 1

Study selection for the umbrella analysis of different dietary exposures and associations with inflammatory bowel disease. CD, Crohn’s disease; IBD, inflammatory bowel disease; UC, ulcerative colitis.

FIGURE 2

Summary of associations from the meta-analyses between dietary exposures and incidence of inflammatory bowel disease. Publishing year is listed within the parentheses. ∗Comparisons are mostly high compared with low consumption [HL] or presented by grams per day (e.g., 50 g, 100 g, or 200 g), and mostly presented as relative risk ratio (RRR). A2, AMSTAR-2 rating (classified as high/medium/low/critically low); ALA, alpha linolenic acid; CC, case control; CI, confidence interval; Co, cohort; CS, cross sectional; DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid; fe, fixed effects; I², heterogeneity (%); MUFA, monounsaturated fatty acid; OR, odds ratio; PUFA, polyunsaturated fatty acid; SFA, saturated fatty acid.

FIGURE 3

Summary of associations from the meta-analyses between dietary exposures and incidence of ulcerative colitis. Publishing year is listed within the parentheses. ∗Comparisons are mostly high compared with low consumption [HL], and mostly presented as relative risk ratio (RRR). A2, AMSTAR-2 rating (classified as high/medium/low/critically low); CC, case control; Co, cohort; CS, cross sectional; DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid; fe, fixed effects; I², heterogeneity (%), MUFA, monounsaturated fatty acid; OR, odds ratio; PUFA, polyunsaturated fatty acid; SFA, saturated fatty acid.

FIGURE 4

Summary of associations from the meta-analyses between dietary exposures and incidence of Crohn’s disease. Reference number is listed in brackets and search year is listed within the parentheses. ∗Comparisons are mostly high compared with low consumption [HL] and mostly presented as relative risk (RR). A2, AMSTAR-2 rating (classified as high/medium/low/critically low); Co, cohort; CC, case control; CS, xxx; DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid; fe, fixed effects; I², heterogeneity (%); MUFA, monounsaturated fatty acid; OR, odds ratio; PUFA, polyunsaturated fatty; SFA, saturated fatty acid.