Posted on Aug 16, 2018, 8 p.m.
Chemicals found within vegetables such as broccoli, kale, and cabbage may help to maintain a healthy gut and prevent colon cancer, as published in Immunity.
Mice fed a diet rich in indole-3-carbinol produced when digesting Brassica genius vegetables were shown to be protected from gut inflammation and colon cancer. Health benefits of vegetables are well documented but many mechanisms behind it remain unclear. This study provides first concrete evidence of how indole-3-carbinol from the diet can help to prevent colon inflammation and cancer via activating aryl hydrocarbon receptor proteins which act as environmental sensors passing signals to immune and epithelial cells in gut lining to protect from inflammatory responses to bacteria residing within the gut.
Mice and mouse gut organoids created from stem cells were studied with results showing aryl hydrocarbon receptor proteins is critical to repairing damaged epithelial cells without which intestinal stem cells fail to differentiate into specialised epithelial cell to absorb nutrients and generate protective mucus, and instead will divide uncontrollable leading to colon cancer.
Genetically modified mice not able to produce or activate aryl hydrocarbon receptor proteins in their guts were found to have readily developed gut inflammation that progressed to colon cancer, when fed diets enriched with indole-3-carbinol the animals did not develop inflammation or colon cancer. Mice with cancer already developing switched to indole-3-carbinol rich diets were observed to develop significantly fewer tumours that were more benign. Normal mice fed standard or indole-3-carbinol enriched diets didn’t develop tumors, those fed a purified controlled diet did.
A variety of vegetable produce chemical which will keep aryl hydrocarbon receptor proteins stimulated in the gut. Aryl hydrocarbon receptor protein promoting chemical in the diet were found to be able to correct defects caused by insufficient AhR stimulation restoring epithelial cell differentiation helping to offer resistance to intestinal infections and prevention of colon cancer, finding providing hope for optimism as genetic factor increasing risk for cancer may not be able to be changed but mitigating risk by adopting appropriate diets with plenty of vegetables can help.
According to the researchers these studies suggest that fibre within vegetables are not the only things to help reduce risk of bowel cancer, other molecules also contribute to risk reduction adding to the evidence supporting a healthy diet rich in vegetable is important to a healthy lifestyle, and additional studies will help to determine whether molecules in vegetables will have the same effect in humans.
Materials provided by The Francis Crick Institute.
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Amina Metidji, Sara Omenetti, Stefania Crotta, Ying Li, Emma Nye, Ellie Ross, Vivian Li, Muralidhara R. Maradana, Chris Schiering, Brigitta Stockinger. The Environmental Sensor AHR Protects from Inflammatory Damage by Maintaining Intestinal Stem Cell Homeostasis and Barrier Integrity. Immunity, 2018; DOI: 10.1016/j.immuni.2018.07.010