Association of Dietary Fiber, Fruit, and Vegetable Consumption with Risk of Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

Abstract

No previous investigation has summarized findings from prospective cohort studies on the association between dietary intake of fiber, fruit, and vegetables and risk of inflammatory bowel disease (IBD). Dietary fiber and its major sources can influence the risk of IBD by modulation of the gut microbiota. This study summarizes findings from published cohort studies on the association between dietary fiber, fruit, and vegetable consumption and risk of IBD. Relevant articles published up to January 2019 were searched via PubMed, MEDLINE, Scopus, Embase, Cochrane Library, and Google Scholar. All prospective cohort studies investigating the association between dietary fiber, fruit, and vegetable intake and risk of IBD were included. Combining 7 effect sizes from 6 studies, no significant association was found between dietary intake of fiber and risk of ulcerative colitis (UC) (RR: 1.09; 95% CI: 0.88, 1.34). However, a significant inverse association was found between dietary fiber intake and risk of Crohn disease (CD) (RR: 0.59; 95% CI: 0.46, 0.74), based on 5 studies with 6 effect sizes. Pooling information from 4 studies, we found a significant protective association between dietary intake of fruit and risk of UC (RR: 0.69; 95% CI: 0.55, 0.86) and CD (RR: 0.47; 95% CI: 0.38, 0.58). We also found a significant inverse association between vegetable consumption and risk of UC (RR: 0.56; 95% CI: 0.48, 0.66) and CD (RR: 0.52; 95% CI: 0.46, 0.59). In conclusion, dietary intake of fruit and vegetables was inversely associated with risk of IBD and its subtypes. Dietary fiber intake was also inversely associated with incidence of IBD and CD, but not with UC. Further studies are warranted to examine the association of other fiber-rich foods with IBD.

Food and Food Groups in Inflammatory Bowel Disease (IBD): The Design of the Groningen Anti-Inflammatory Diet (GrAID)

“…A more recent meta-analysis on four prospective studies [23,67,69,70] demonstrated a significant inverse association between fruit consumption with CD risk (Relative Risk (RR) 0.47; 95% CI: 0.38-0.58; I 2 = 32%) [71]. This association remained significant when analysed in subgroups in servings per day.…”

“…The earlier systematic review on fruit and UC development that also included casecontrol studies, reported that none of eight included studies in the systematic review showed significant results (OR range 0.42-2.9) [41]. In the later systematic review including the same four earlier mentioned studies, a pooled analysis demonstrated that fruit intake (g/day) was significantly associated with UC risk (RR 0.69; 95% CI: 0.55-0.86; I 2 = 87%) [71]. However, this association lost significance when it was performed in 1-3 servings/day in subgroups.…”

“…Patients consuming more vegetables were less likely to have CD (OR 0.85 95% CI: 0.74-0.97) [44]. A more recent meta-analyses including three prospective studies [23,69,70] demonstrated a significant inverse association of vegetable consumption (g/day) with odds of CD (RR 0.52; 95% CI: 0.46-0.59; I 2 = 79%) [71].…”

The Role of Diet in the Pathogenesis and Management of Inflammatory Bowel Disease: A Review

“…A smaller case-control study including men and women showed benefit in the subgroup of patient's with CD who were non-smokers [49]. A recently published systematic review with meta-analysis examined the association of dietary fibre, fruit and vegetable consumption with risk of IBD [58]. There was no significant association between dietary intake of fibre and risk of UC.…”

Inflammatory Bowel Diseases: Is There a Role for Nutritional Suggestions?

“…When substrate is scarce, intestinal bacteria use the intestinal mucus as a nutrient, which leads to inflammation through close contact between bacteria and the epithelial layer [37]. Long-term intake of fibers from fruit has been shown to be protective against the development of CD, but not of UC [38][39][40][41][42].…”