Kale Family of Vegetables Could Prevent Common Form of Cancer, Mice Study Suggests

Vegetables have been linked to a lower risk of colon cancer in mice. Getty Images

Vegetables including kale, cabbage and broccoli are packed with chemicals that could prevent colon cancer, according to a study in mice.

Scientists found mice who were fed a diet containing a chemical found in the brassica family of plants had healthier guts, and were less likely to develop inflammation and colon cancer. This form of the disease is the third most common in men and women.

When the body digests vegetables from the brassica genus, it produces indole-3-carbinol (I3C).

According to the authors behind the study, published in the journal Immunity, I3C appears to have cancer-preventing abilities because it activates a protein called the aryl hydrocarbon receptor (AhR).

This protein sends signals to immune cells and epithelial cells (the first line of defense against harmful bacteria and viruses) that line the gut. These prevent the gut from becoming inflamed when confronted by bacteria that inhabit the digestive system.

"When we fed [the mice] a diet enriched with I3C, they did not develop inflammation or cancer," explains first author Dr Amina Metidji from the Francis Crick Institute.

"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."

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To arrive at their conclusion, the team genetically modified mice to not produce or activate AhR in their guts. They found their guts became inflamed and the animals eventually developed colon cancer.

The team found similar results in gut organoids made from stem cells. AhR is key for repairing damaged epithelial cells: and stem cells without the protein couldn't tell the difference between specialized epithelial cells that produce protective mucus and those that soak up nutrients. As a result they divided uncontrollably, which appeared to lead to colon cancer.

Dr. Gitta Stockinger, senior author of the paper and a molecular immunologist at the Francis Crick Institute, told Newsweek: "While there are many reports linking consumption of vegetables to improved health there was so far no molecular basis for this. Our study shows what component of vegetables affects the intestinal barrier and how it does so."

"While we cannot influence our genes that may predispose us to certain diseases, we can do something about the environmental influences via our diet to ensure that our protective gut barrier is optimally supported. You probably cannot eat too many vegetables."

However, Dr. Marjorie Lynn McCullough, American Cancer Society epidemiologist, cautioned the results need further investigation and to be replicated in humans, as results in mice aren't directly comparable.

"The authors studied one compound found in certain plant foods. Isolated compounds may have different actions than when consumed in food," she told Newsweek.

Scientific research does suggest, however, that eating processed and red meat increases the risk of colon cancer, she said. "Cancer prevention guidelines currently advise eating a diet rich in a variety of vegetables, fruit and whole grains, and low in processed meat and red meat. This type of an overall dietary pattern is related not only to lower cancer risk, but to lower risk of other chronic diseases, such as cardiovascular disease and diabetes."

Professor Tim Key, an expert on diet and cancer at the charity Cancer Research UK, said: "This study in mice suggests that it's not just the fiber contained in vegetables like broccoli and cabbage that help reduce the risk of bowel cancer, but also molecules found in these vegetables too. This adds to the evidence that a healthy diet, rich in vegetables, is important."