Background and aims: enteral (EN) and parenteral (TPN) nutrition exert variable therapeutic effects on the induction and maintenance of remission in inflammatory bowel disease (IBD).This review aims to provide an updated discussion on the complex relationship between diet and IBD.Methods: medline, Cochrane and Scopus database searches were conducted. Sources cited in the articles obtained were also searched to identify other potential sources of information.Results: nutritional status is significantly compromised in IBD patients, especially those with Crohn's disease (CD). Apart from restoring malnourishment, dietary components contribute to modulate intestinal immune responses. Nutritional treatment is divided into support therapy and primary therapy to induce and maintain remission through TPN and EN. EN is considered a first-line therapy in children with active CD whereas it is usually used in adult CD patients when corticosteroid therapy is not possible. TPN has limited effects on IBD.En formula composition, in terms of carbohydrates, nitrogen source and bioactive molecules supplementation, differentially influence on IBD treatment outcomes. Other dietary components, such as poorly absorbed short-chain carbohydrate, polyols, and exogenous microparticles, also participate in the etiopathogenesis of IBD. Finally, new approaches to understanding the complex relationship between IBD and diet are provided by nutrigenenomic.Conclusion: further long-term, well-powered studies are required to accurately assess the usefulness of nutrition in treating IBD. In future research, the potential role of nutrient-gene interaction in drug trials and specific dietary formula compositions should be investigated in order to incorporate new knowledge about the etiopathology of IBD into nutritional intervention.