Background and purpose: published studies have assessed the effect of protein intake on Crohn's disease (CD) and ulcerative colitis (UC). However, the results were inconsistent. To provide a more precise estimation, a meta-analysis was performed to evaluate the association of protein intake in Crohn's disease and ulcerative colitis.
Methods: the PubMed, Chinese National Knowledge Infrastructure databases (CNKI), and Wanfang databases were searched to identify relevant studies. The summarized results of the relative risk (RR) with the corresponding 95 % confidence intervals (CI) were calculated using a random effects model.
Results: the final analysis included a total of nine articles. Nine studies reported on protein intake for the risk of UC and five studies reported on protein intake for the risk of CD. Overall, based on current studies, no significant association was found between protein intake and the risk of UC (RR = 1.13, 95 % CI = 0.82-1.55) or CD (RR = 1.18, 95 % CI = 0.51-2.74). A significant change was not found in the stratified analysis by study design and geographic location.
Conclusions: in conclusion, the present meta-analysis suggested that dietary protein intake did not show a significant effect on the risk of UC or CD.