Gluten sensitivity was reported in 23.6 and 27.3% of Crohns disease and ulcerative colitis patients, respectively.A diet high in protein, particularly animal protein, and/or high in sugar may be associated with increased risk of inflammatory bowel disease and relapses. Microbiota
As a result of microbial symbiosis and immunity, alterations in the gut microbiome may contribute to inflammatory gut diseases. IBD-affected individuals have been found to have 30–50 percent reduced biodiversity of commensal bacteria, such as decreases in Bacillota (namely Lachnospiraceae) and Bacteroidota. Further evidence of the role of gut flora in the cause of inflammatory bowel disease is that IBD-affected individuals are more likely to have been prescribed antibiotics in the 2–5 year period before their diagnosis than unaffected individuals. The enteral bacteria can be altered by environmental factors, such as concentrated milk fats (a common ingredient of processed foods and confectionery) or oral medications such as antibiotics and oral iron preparations. The mucosal microbiota in the large intestine of IBD patients with active inflammation was found to be associated with pro-inflammatory changes to the host epigenome. However, large international studies have failed to identify a single microbial biomarker of IBD indicating its not driven by any single micro-organism. Breach of intestinal barrier
Loss of integrity of the intestinal epithelium plays a key pathogenic role in IBD.
Increased expression of ICAM-1 has been observed within the inflamed intestinal mucosa of people with ulcerative colitis, pouchitis and Crohns, where ICAM-1 over production correlated with disease activity. This suggests that ICAM-1 is a potential therapeutic target in the treatment of these diseases.Cannabinoid CB2 receptor agonists are found to decrease the induction of ICAM-1 and VCAM-1 surface expression in human brain tissues and primary human brain endothelial cells (BMVEC) exposed to various pro-inflammatory mediators.In 2014, an alliance among the Broad Institute, Amgen and Massachusetts General Hospital formed with the intention to "collect and analyze patient DNA samples to identify and further validate genetic targets. "In 2015, a meta-analysis on 938 IBD patients and 953 controls, IBD was significantly associated with having higher odds of vitamin D deficiency.Gram-positive bacteria present in the lumen could be associated with extending the time of relapse for ulcerative colitis.Bidirectional pathways between depression and IBD have been suggested  and psychological processes have been demonstrated to influence self-perceived physical and psychological health over time. IBD-disease activity may impact quality of life and over time may significantly affect individuals mental well-being, which may be related to the increased risk to develop anxiety and/or depression. On the other hand, psychological distress may also influence IBD activity.Higher rates of anxiety and depression are observed among those with IBD compared to healthy individuals, which correlated with disease severity. Moreover, anxiety and depression rates increase during active disease compared with inactive phases. See also
Inflammatory bowel disease-22
World Inflammatory Bowel Disease Day

References
External links
Inflammatory bowel disease at Curlie