Diets ‘devoid of vegetable matter’ may cause colon cancer

A new study emphasizes the importance to gut health of eating plenty of vegetables such as cabbage, broccoli, and kale.
selection of greens
Eating brassicas such as collards, kale, and broccoli may protect against colon cancer.
Researchers from the Francis Crick Institute in London, United Kingdom, found that keeping mice on a diet rich in a compound known as indole-3-carbinol (I3C) — which comes from such vegetables — prevented the animals’ intestines from becoming inflamed and developing colon cancer.

They report the study in a paper now published in the journal Immunity.

“Seeing the profound effect,” says study senior author Dr. Brigitta Stockinger, a group leader at the Francis Crick Institute, “of diet on gut inflammation and colon cancer was very striking.”

Our digestive system produces I3C when we eat vegetables from a “large and diverse group” of plants known as brassicas.

Brassicas include, but are not limited to: broccoli, cabbage, collards, Brussels sprouts, cauliflower, kale, kohlrabi, swede, turnip, bok choi, and mizuna.

Colon cancer typically starts as a growth, or polyp, in the lining of the colon or large intestine. It can take many years for the cancer to develop from a polyp and not all polyps become cancerous.

Cancer of the colon or rectum is the third most commonly diagnosed in both women and men in the United States, not counting skin cancer.

The American Cancer Society (ACS) estimate that there will be 97,220 new cases of diagnosed colon cancer in the U.S. in 2018.

‘Concrete evidence’ of hidden mechanism
Despite a lot of evidence about the benefits to our digestive system of a diet rich in vegetables, much of the underlying cell biology remains unknown.

The new findings are the first to give “concrete evidence” of how dietary I3C — through its effect on a cell protein known as aryl hydrocarbon receptor (AhR) — protects the gut from inflammation and cancer.

AhR has several roles, and for it to work properly, it has to be activated by a compound that binds to it uniquely. I3C is such a compound.

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One of AhR’s jobs in the gut is to pick up environmental signals and pass them on to immune cells and other cells in the lining. These signals are important for protecting the digestive tract from inflammation-promoting signals that come from the “trillions of bacteria” that live in it.