A potential mechanism by which cholesterol rich, ‘Western-style’ diets can lead to inflammatory gut problems, is reported in Nature Communications this week. The mechanism, described in zebrafish, may improve our understanding of how what we eat affects our health.
Increasingly common, Western-style diets have been linked to chronic inflammatory intestinal problems, such as ulcerative colitis and Crohn’s disease; however, the mechanisms linking diet and disease remain unclear. Margaret Dallman and colleagues find that, within hours of eating cholesterol rich food (clotted cream diluted in their water), zebrafish, quickly develop an inflammatory response in the intestine. The authors show that this is caused directly by the binding of cholesterol to a protein found on the epithelial cells that line the gut, and is also indirectly caused by signalling from gut-dwelling microbes. Together these signals trigger the activation of the inflammasome, a multi-protein complex that initiates inflammation, in intestinal epithelial cells.
After ten days on a cholesterol rich diet, normal peristalsis - the muscular wave of contraction and relaxation that moves food along the gastro-intestinal tract - was found to be impaired, a hallmark of gastro-intestinal disorders such as irritable bowel syndrome. Taken together, these results suggest that acute inflammatory responses in the gut may contribute to longer-term health problems. However, more research is necessary to determine whether these findings are relevant to humans.