Systematic Review With Meta-analysis

Dietary Intake in Adults With Inflammatory Bowel Disease

Kelly Lambert; Daniel Pappas; Chiara Miglioretto; Arefeh Javadpour; Hannah Reveley; Laura Frank; Michael C. Grimm; Dorit Samocha-Bonet; Georgina L. Hold


Aliment Pharmacol Ther. 2021;54(6):742-754. 

In This Article

Abstract and Introduction


Background: Poor dietary intake is associated with the development of malnutrition, micronutrient deficiencies, anaemia and osteoporosis in individuals with inflammatory bowel disease. While trials are underway to manipulate the diet of people with IBD, there has been no comprehensive systematic review of the dietary intake of adults with IBD.

Aims: To conduct a systematic evaluation and meta-analysis of the dietary intake of adults with IBD, including macronutrients, micronutrients and food group data.

Methods: CINAHL, Embase, Medline and Scopus were searched from 1 January 2000 to 25 September 2020 for cohort, case–control or cross-sectional studies that reported usual dietary intake in adults. Data were pooled and reported as weighted mean intake for: all adults with IBD; Crohn's disease; ulcerative colitis; active disease; remission; males; females. A random-effects meta-analysis model compared intake with healthy individuals.

Results Forty studies were identified and 19 were included in the meta-analysis. All subgroups of adults with IBD consumed inadequate energy (mean intake in adults with IBD 1980 ± 130 kcal), fibre (14 ± 4 g), folate (246 ± 33 mg) and calcium (529 ± 114 mg) per day. Intake of breads and cereals, legumes, fruit, vegetables and dairy were inadequate. Compared to healthy individuals, adults with IBD consume significantly less dietary fibre (SMD −0.59; 95% CI: −0.73, −0.46).

Conclusions: This review provides improved clarity about the dietary intake of adults with IBD. Future attention is required to improve diet quality and increase understanding of factors influencing dietary intake in IBD.


Inflammatory bowel diseases (IBD) are chronic inflammatory conditions that encompass two distinct disorders: ulcerative colitis and Crohn's disease. Factors such as genetics,[1] dysfunction in inflammatory responses by the innate and adaptive immune system,[2] environmental exposure during childhood,[3] diet[4,5] and the gut microbiota have been shown to contribute to the development and progression of the IBD.[6]

The nutrient intake and dietary patterns of people with IBD are of great interest to the research and patient community.[7] Evidence is available that diets high in total fat, polyunsaturated fatty acids, soft drinks and meat and low intakes of fibre from fruits and vegetables are associated with the development of IBD,[8–11] and clinical trials investigating modification of the diet to reduce symptoms and inflammation are ongoing.[12,13] Reports also exist that describe a range of suboptimal dietary patterns[14,15] or food aversions[16–18] in people with IBD that place them at risk of developing micronutrient deficiency and malnutrition. Suboptimal dietary behaviours may be in part related to the desire to avoid worsening of symptoms,[15] as well as misinformation and/or lack of access to specific dietetic guidance.[14] Despite the large number of studies examining the dietary intake of people with IBD, and the increased prevalence of nutrition-related disorders[19] in people with IBD there have been no systematic reviews to date that have comprehensively summarised the evidence regarding the usual macronutrient, micronutrient and core food group intake of people with IBD.

Given this evidence gap, the aim of this systematic review and meta-analysis was to synthesise and describe the usual dietary intake of adults with IBD and determine whether the reported usual dietary intake of adults with IBD differs from controls. This information could be used to inform the development of resources for clinical care, target interventions to improve the health of people with IBD and design future dietary intervention trials.