Exclusion diet and fasting practices in patients with inflammatory bowel disease: Impact on nutritional status.

Background: Undernutrition is purportedly highly prevalent in inflammatory bowel diseases (IBD). While several risk factors have been identified, the impact of widespread eating behaviors such as food exclusions and therapeutic fasting practices has not been evaluated. There are limited data on the prevalence of undernutrition diagnosed according to internationally recognized criteria in this population.

Objectives: To estimate the prevalence of undernutrition assessed with the Global Leadership Initiative on Undernutrition (GLIM) criteria and to analyze factors associated with the characteristics of the disease and factors related to undernutrition.

Methods: Patients attending our IBD nutrition clinic were screened between November 2021 and April 2022. The complete avoidance of a food category was defined as total exclusion while avoidance most of the time was defined as partial exclusion. Undernutrition was diagnosed according to GLIM criteria. Weight history, past maximal involuntary weight loss and minimal body mass index since diagnosis of IBD were also collected.

Results: A total of 434 patients with IBD were included. Undernutrition was observed in 25.8 % of the whole population at inclusion (15 % with moderate undernutrition and 10.8 % with severe undernutrition). Mean involuntary maximal weight loss since illness onset was -14.5 % ± 11.0. Previous undernutrition since IBD diagnosis was reported in 81.1 % of the population, 63.6 % for severe and 17.5 % for moderate undernutrition. In multivariate analysis, undernutrition at inclusion was independently associated with total exclusion of at least one food category (OR = 1.11 95 % CI, 1.01-1.22; p = 0.031) as well as active disease (OR = 1.16 95 % CI, 1.05-1.27; p = 0.002), and negatively with the duration of IBD (OR = 0.88 95 % CI, 0.78-0.99, p = 0.031). Exclusion diet was also the main variable significantly associated with episodes of undernutrition in the past (OR = 1.11 95 % CI, 1.01-1.22; p = 0.035) as well as previous surgery (OR = 1.11 95 % CI, 1.00-1.23; p = 0.048). In these analyses, fasting practices were not independently associated with a risk of undernutrition.

Conclusion: Total exclusion of at least one food category was one of the main factors associated with undernutrition independently of disease activity and duration, both at the time of inclusion and in the past, and should be avoided, whereas fasting practices were not associated with a risk of undernutrition.