I have both IBD and IBS so I thought that this is the appropriate place to post this.... which I stumbled on at an IBD forum. The link apparently requires a membership but the person who posted this was kind enough to type out the text of the article.

Correlation is not causation but the article is interesting nevertheless, and maybe it's yet another reason for many of us to stay away from potatoes .... (P.S. alot of people with IBD like me benefit from LCing and it might be nice to relabel this forum section "Canada/yeast/IBS/IBD.")

http://www.medscape.com/viewarticle/553039

Epidemiologic studies have indicated that the prevalance of IBD is directly correlated to consumption of fried potato products.

Altered intestinal permeability is believed by some to play a key role in the initiation and propagation of the inflammatory process. It is thought that bacterial products or even bacteria themselves may penetrate this altered epithelial barrier, activating the intestinal immune system. Potatoes have a high concentration of glycoalkaloids, specifically alpha-solanine and alpha-chaconine. These molecules "permeabilize cholesterol-containing membranes" and this is believed to alter the intestinal epithelial barrier. These glycoalkaloids are concentrated when potatoes are fried.

These molecules are present in potato as a sort of defense mechanism for the potato plant, playing a key role in defending the plant against fungi, bacteria, and parasites. However, these molecules have been shown to adversely affect the permeability of epithelial cells in the intestine, and this may aggrevate IBD. These compounds have been shown to adversely affect the intestine permeability in an IL-10 deficient mice model of colitis, but not in normal mice, suggesting that those patients with IBD may be predisposed to this adverse effect.