Why IBD Patients Aren't Eating 'an Apple a Day:' Understanding Dietary Fiber Avoidance in Inflammatory Bowel Disease

Introduction: Patients with inflammatory bowel disease (IBD) are at increased risk of malnutrition and micronutrient deficiencies, which may be potentially worsened by self-imposed dietary restrictions of nutritious, fiber-rich foods. We aimed to understand dietary fiber avoidances during remission and active disease between patients with Crohn's Disease (CD) and Ulcerative Colitis (UC). Methods: A cross-sectional study of dietary preferences in an IBD patient cohort seen in 2 academic GI practices. A dietary questionnaire was used to assess high-fiber foods avoided during remission and active disease. Fiber sources evaluated included leafy vegetables, cruciferous/brassicas, other vegetables, fruits, citrus, tomatoes, legumes, gluten/wheat, bread, and cereal. The Malnutrition Screening Tool (MST) was used to assess malnutrition risk in study patients with a score ≥2 considered moderate-high risk. Results: 133 patients (78 CD, 55 UC). 25.7% vs 12.7% (CD vs UC) were at moderate-high risk of malnutrition. In remission, patients reported no significant difference in avoidance rates of various fiber sources between CD and UC (Table 1). In active disease, there was no significant difference in avoidance rates of various fiber sources between CD and UC. However, we noted significant differences in fiber avoidance rates between remission vs active disease, which was more pronounced in CD (Figure 1). Specifically, CD patients reported significantly increased fiber avoidance during active disease of cruciferous, leafy, and other vegetables, fruits, citrus, tomato, and legumes- while UC patients only significantly increased avoidance of leafy vegetables and other vegetables in active disease. During active and inactive disease, patients reported GI intolerance as the most common reason for food avoidance (57% and 51%, respectively) with fear of worsening IBD symptoms (16% and 42%) second. Most patients chose these food avoidances without medical guidance (68% in inactive and 59% in active disease). Conclusion: Self-imposed food avoidances are frequent in IBD patients and more common in those with active disease and in CD. Given significant risks of malnutrition in IBD, providers should recognize dietary avoidances, including fiber avoidances, with nutrition consultations being sought in higher risk patients. Our findings imply that varied fiber sources may be tolerated differently between CD and UC. Further studies are needed to help provide tailored advice when providing nutritional counseling to IBD patients.Figure 1.: Comparison of fiber avoidance rates of various dietary fiber sources during remission vs active disease in Crohn’s Disease and Ulcerative Colitis patients. Table 1. - Comparison of fiber sources avoided during perceived clinical remission and active disease between Crohn’s Disease and Ulcerative Colitis patients Fiber Sources Avoided CD (n=78) UC (n=55) P-value During Clinical Remission Cruciferous/Brassicas 10 (12.8%) 7 (12.7%) 1.0 Green Leafy Vegetables 14 (17.9%) 4 (7.3%) .12 Vegetables (other) 7 (9.0%) 3 (5.5%) .52 Fruits 5 (6.4%) 4 (7.3%) 1.0 Citrus 4 (5.1%) 4 (7.3%) .71 Tomato 7 (9.0%) 7 (12.7%) .57 Legumes 14 (17.9%) 12 (21.8%) .66 Gluten/Wheat 16 (20.5%) 10 (18.2%) .83 Cereal 9 (11.5%) 6 (10.9%) 1.0 Bread 8 (10.3%) 5 (9.1%) 1.0 During Active Disease Cruciferous/Brassicas 21 (26.9%) 12 (21.8%) .55 Green Leafy Vegetables 32 (41%) 15 (27.3%) .14 Vegetables (other) 24 (30.8%) 13 (23.6%) .43 Fruits 17 (21.8%) 11 (20%) .83 Citrus 18 (23.1%) 12 (21.8%) 1.0 Tomato 22 (28.2%) 12 (21.8%) .43 Legumes 32 (41.0%) 16 (29.1%) .20 Gluten/Wheat 12(15.4%) 10(18.2%) .81 Cereal 7 (9.0%) 9 (16.4%) .28 Bread 6 (7.7%) 7 (12.7%) .38