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S recent study from Japan on why CD has increased significantly in that country in the last 20 years
http://www.medscape.com/viewarticle/585406
Summary
Case-control studies and epidemiological data have suggested that eating too much Westernized food could increase the occurrence of IBD. A recent study implicated that intestinal microbes might be involved in the induction of IBD. However, there is a time lag between the increased number of patients with IBD and alterations in Westernized food consumption. That is, an increase in the number of patients with IBD was observed approximately 20 years after an increased consumption of animal-derived food and the reduction in rice consumption. A high incidence of IBD was observed the second to third decades of life in CD and in third to fourth decades in UC. It may take approximately two or three decades to develop IBD symptoms in humans. Even in the susceptible gene-bearing animals developing the spontaneous colitis, it took 5–7 weeks after birth in T-cell receptor mutant mice, 6–15 weeks in mice with a disrupted IL-2 gene, and 12 weeks in IL-10 knockout mice to develop spontaneous colitis, respectively.[78–80] Mizoguchi et al. reported on appendectomy at a young age (3–5 weeks) with T-cell receptor-α mutant mice suppressing the development of colitis. However, after 3–5 weeks, it was difficult to protect mice from developing colitis.[81] This fact may imply that a long-term exposure to intestinal antigens is needed to develop clinical manifestation of IBD.
The present study supports that intestinal environmental factors, such as food and microbes, are very important for the pathogenesis of IBD. However, further studies are needed, because most studies lack direct evidence of a direct link to the pathogenesis of IBD. A case-control study does not necessarily clarify the precise dietary habits that induce IBD, because most patients with IBD had dietary beliefs to avoid harmful food.[82] As it can take 5–15 weeks for rats and mice to develop colitis spontaneously, it is difficult to assess the long-term effects of dietary habits before the development of IBD in each patient.
http://www.medscape.com/viewarticle/585406
Summary
Case-control studies and epidemiological data have suggested that eating too much Westernized food could increase the occurrence of IBD. A recent study implicated that intestinal microbes might be involved in the induction of IBD. However, there is a time lag between the increased number of patients with IBD and alterations in Westernized food consumption. That is, an increase in the number of patients with IBD was observed approximately 20 years after an increased consumption of animal-derived food and the reduction in rice consumption. A high incidence of IBD was observed the second to third decades of life in CD and in third to fourth decades in UC. It may take approximately two or three decades to develop IBD symptoms in humans. Even in the susceptible gene-bearing animals developing the spontaneous colitis, it took 5–7 weeks after birth in T-cell receptor mutant mice, 6–15 weeks in mice with a disrupted IL-2 gene, and 12 weeks in IL-10 knockout mice to develop spontaneous colitis, respectively.[78–80] Mizoguchi et al. reported on appendectomy at a young age (3–5 weeks) with T-cell receptor-α mutant mice suppressing the development of colitis. However, after 3–5 weeks, it was difficult to protect mice from developing colitis.[81] This fact may imply that a long-term exposure to intestinal antigens is needed to develop clinical manifestation of IBD.
The present study supports that intestinal environmental factors, such as food and microbes, are very important for the pathogenesis of IBD. However, further studies are needed, because most studies lack direct evidence of a direct link to the pathogenesis of IBD. A case-control study does not necessarily clarify the precise dietary habits that induce IBD, because most patients with IBD had dietary beliefs to avoid harmful food.[82] As it can take 5–15 weeks for rats and mice to develop colitis spontaneously, it is difficult to assess the long-term effects of dietary habits before the development of IBD in each patient.
