The association of ultra-processed food consumption with adult inflammatory bowel disease risk: a systematic review and dose-response meta-analysis of 4 035 694 participants

There is an inconsistency between the results obtained from observational studies regarding intake of ultra-processed foods (UPFs) and the risk of inflammatory bowel disease (IBD).A dose-response meta-analysis was performed to evaluate the relationship between UPF intake and the risk of IBD.Searches were performed in the PubMed, ISI Web of Science, and Scopus databases up to November 2, 2022.Data were available from 24 studies including a total of 4 035 694 participants from 20 countries.Risk ratios for IBD were analyzed by a random-effects model. Outcomes indicated that UPF intake was linked to an increased risk of IBD (relative risk [RR], 1.13; 95%CI, 1.06-1.21; P = 0.001; I2 = 73.2%; n = 59; N = 4 035 694). This association was significant, especially for the risk of Crohn's disease (CD) (RR, 1.19; 95%CI, 1.00-1.41; I2 = 78.2%; P = 0.046; n = 23; N = 2 167 160), unlike the risk of ulcerative colitis (UC) (RR = 1.11; 95%CI, 0.99-1.26; P = 0.085; I2 = 60.3%; n = 27; N = 2 167 918). Also, results revealed that each 10% enhancement in daily UPF intake was not related to the risk of IBD (RR, 1.05; 95%CI, 0.98-1.14; P = 0.168; I2 = 31.9%; n = 4) or the risk of UC (RR, 1.01; 95%CI, 0.92-1.11; P = 0.876; I2 = 34.7%; n = 2) in adults. However, results suggested that for every 10% increase in daily UPF intake, there was a 19% increase in the risk of CD (RR, 1.19; 95%CI, 1.01-1.32; P = 0.021; I2 = 0.0%; n = 2) among adults. In addition, the results showed a positive linear relation between UPF intake with CD risk (Pnonlinearity = 0.431; Pdose response = 0.049) but not risk of IBD or UC.High intake of UPFs was linked with an enhanced IBD risk, a specific risk of CD. However, conducting more observational studies among several ethnicities and using specific tools that accurately assess the amount of UPF consumption, components of UPFs, and food additives may be necessary. Systematic Review Registration: PROSPERO registration no. CRD42023390258.