Nutrient requirements for adults with ulcerative colitis over the disease course: a systematic scoping review

Ulcerative colitis (UC) is a chronic inflammatory disease affecting the colonic mucosa. Nutrient requirements for UC are often extrapolated from studies in Crohn's disease (CD) yet physiological differences between UC and CD phenotypes may result in distinct nutrient requirements. This scoping review aimed to evaluate nutrient requirements for adults with UC. A scoping review with a systematic search strategy was conducted to June 2025. Data were extracted to identify nutrient requirements stratified by disease activity. Twenty-one studies involving 617 adults (274 male) were included. Measured resting energy expenditure (mREE) via indirect calorimetry ranged from 28.9 ± 3.2 to 31.5 ± 4.8 kcal/kg (fat free mass)/day (d) in quiescent UC, 26.4 kcal/kg/d in mild-moderate disease and 23.9 kcal/kg/d in acute severe UC (ASUC). Protein requirement, from historic studies, were 1.2-1.4 g/kg/d in ASUC. Protein requirements in quiescent or mild to moderate UC and whether elevated protein requirements persist in today's biologic era, remain unknown. Micronutrient requirement was investigated in mixed disease activity states confounding results. Evidence is insufficient to determine whether chronic inflammation in UC alters macro- and micronutrient requirements. Historical studies suggest increased protein requirements in ASUC, without evidence for quiescent or mild-moderate disease. Well-designed and disease activity-stratified studies are needed to establish evidence-based nutrient recommendations in UC.