Is there a link between food and intestinal microbes and the occurrence of Crohn's disease and ulcerative colitis?

The pathogenesis of Crohn's disease (CD) and ulcerative colitis (UC) is not fully understood. The interaction between intestinal environmental factors of food and intestinal microbes and the immunological system of hosts seems to be an important aspect. We have reviewed the relationship of the daily consumption of dietary animal meat and fats, dairy products, sugar, and other factors that may be linked to the occurrence of CD and UC from the literature and Japanese epidemiological data.