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Eating these vegetables may help to prevent colon cancer

A new study from the Francis Crick Institute suggests that vegetables such as kale, broccoli, and cabbage could help prevent gut inflammation and colon cancer. The researchers have discovered that the mechanism underlying these health benefits is a protein that is activated by a diet rich in indole-3-carbinol (I3C).

As our bodies digest vegetables from the Brassica genus, I3C is produced. The researchers found that mice who received regular doses of I3C were protected from gut inflammation and colon cancer.

This study is the first of its kind to show how vegetables in the diet can protect the colon and the gut by activating a protein called the aryl hydrocarbon receptor (AhR). This protein sends signals to immune cells and epithelial cells in the lining of the gut to prevent inflammatory responses to trillions of bacteria that are present.

“We studied genetically modified mice that cannot produce or activate AhR in their guts, and found that they readily developed gut inflammation which progressed to colon cancer,” explained study first author Dr. Amina Metidji.

“However, when we fed them a diet enriched with I3C, they did not develop inflammation or cancer. Interestingly, when mice whose cancer was already developing were switched to the I3C-enriched diet, they ended up with significantly fewer tumors which were also more benign.”

The analysis of mouse gut organoids made from stem cells revealed that AhR is critical for repairing damaged epithelial cells. Intestinal stem cells need AhR to differentiate into specialized epithelial cells that absorb nutrients. Without it, the stem cells divide uncontrollably, which can ultimately lead to colon cancer.

“Seeing the profound effect of diet on gut inflammation and colon cancer was very striking,” said senior author Dr. Gitta Stockinger. “We often think of colon cancer as a disease promoted by a Western diet rich in fat and poor in vegetable content, and our results suggest a mechanism behind this observation.”

“Many vegetables produce chemicals that keep AhR stimulated in the gut. We found that AhR-promoting chemicals in the diet can correct defects caused by insufficient AhR stimulation. This can restore epithelial cell differentiation, offering resistance to intestinal infections and preventing colon cancer.”

“These findings are a cause for optimism; while we can’t change the genetic factors that increase our risk of cancer, we can probably mitigate these risks by adopting an appropriate diet with plenty of vegetables.”

The team hopes to follow up on this research with additional experiments in organoids made from human gut biopsies and human trials.

“A number of epidemiological studies suggested that vegetables may be protective against cancer,” said Dr. Gitta. “However, there is very little literature on which vegetables are the most beneficial or why. Now that we’ve demonstrated the mechanistic basis for this in mice, we’re going to investigate these effects in human cells and people. In the meantime, there’s certainly no harm in eating more vegetables!”

The study is published in the journal Immunity.

By Chrissy Sexton, Staff Writer

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