Collagen

Basically the idea is that since a) the gut lining is partially comprised of collagen and b) people with IBD issues have lower serum collagen, then perhaps increasing your consumption of collagen could help the body strengthen the gut boundary and help reduce IBD-related issues. As far as I know there haven't been any human trials showing this yet, but here is a rat study promoting glycine and a pig study promoting glutamate:Studies on the antisecretory, gastric anti-ulcer and cytoprotective properties of glycine.