**4.5 Role of dietary interventions on inflammatory bowel disease (IBD)**

The triggers of IBD include internal (enteric microflora) and external (food) triggers [134]. Overconsumption of sugar and refined carbohydrates was associated with the manifestation of Crohn's disease. Furthermore, excess intake of sugar over the years could alter the intestinal bacterial flora and general milieu, which could damage the mucosa or alter bile acid composition. These alterations could be the result of infective agents or sugar fermentation [135]. A balanced diet that includes fruits, vegetables, meat, olive oil, and fish (blue fish particularly) should be prescribed to IBD patients. Insoluble fiber might have negative effects in case of major intestinal stenosis coexisting with IBD. However, insoluble fiber intake should not be restricted in IBD patients. Moreover, dairy products are a crucial part of IBD nutrition intervention due to their calcium content. Products that contain lactose could be avoided if the patient had lactose intolerance and substituted with plant-based products that contain enough calcium. Supplementation with calcium and vitamin D3 might be required along with systemic steroids treatment as well as other treatments that have greater local effects such as budesonide or beclomethasone. Furthermore, iron and folic acid deficiencies should be closely monitored due to their huge prevalence in IBD patients. Deficiencies in iron or folic acid contribute to anemia in this population and could be easily treated orally or intravenously [134].
