The Impact of Red Meat and Whole-grains Intake on the Colonic Mucus' Thickness, Colonic MUC-2 Expression Rate and the Inflammatory Markers in the Blood.

The mucus layer in the colon is a continuous barrier separating the epithelial cells from faecal enzymes, bacteria, toxic and other components. The colonic mucus layer in patients with Crohn's Disease and Ulcerative Colitis was previously demonstrated to be thinner and more permeable compared to healthy subjects.

The colonic mucus is composed of glycoproteins held together trough unstable disulfide bridges. The digestion of red meat is associated with monosulfide production, which could bind to the disulfide molecules, make more stable trisulfide molecules, and thus destroy the mucus architecture. Moreover, different bacteria were previously linked to red meat intake and were associated with a degradation of the colonic mucus such as akkermansia muciniphila.

From the other side, the fermentation of the undigested fibres, primarily in whole-grains, is associated with the production of short-chain fatty acids, which was related to a local anti-inflammatory effect.

In this study, we hypothesise:

1. High consumption of red meat is associated with a thinner colonic mucus layer;
2. High consumption of whole-grain fibres is associated with a thicker colonic mucus layer;
3. Mucin-2 gene expression is different between patients with high red meat consumption vs low red meat consumption;
4. Mucin-2 gene expression is different between patients with high whole-grain consumption vs low whole-grain intake;
5. The level of inflammatory markers in blood "IL-1beta, IL-4, IL-6, IL-10, Hs-CRP, and TNF-alfa is higher in subjects with high red meat and low whole-grain intake.