Newsflash: Vegetables are good for you! OK, so this may not exactly be news, but a new study from a team of researchers at Imperial College London and The Francis Crick Institute has revealed for the first time one of the key biological mechanisms at play, explaining exactly how a certain chemical produced by eating specific vegetables can prevent cancer and colon inflammation.

"A number of epidemiological studies suggested that vegetables may be protective against cancer," explains Gitta Stockinger, senior author on the new research. "However, there is very little literature on which vegetables are the most beneficial or why."

The research centers on a vital protein called aryl hydrocarbon receptor (AhR). This molecule is important for regulating inflammation in the gut, acting a little like an environmental sensor modulating the activity of immune cells. It was initially found that mice modified to lack AhR quickly displayed out of control gut inflammation leading to colon cancer.

The key to stimulating AhR was found in a chemical called indole-3-carbinol (I3C). This chemical is produced in our guts when we digest vegetables such as broccoli, cabbage and kale, plants from the Brassica genus. When the mice deficient in AhR were fed food enriched with I3C they did not display the same pro-inflammatory traits as before. Even further, when mice with already developed cancer were fed I3C-enriched food, they developed fewer, and more benign, tumors.

"Seeing the profound effect of diet on gut inflammation and colon cancer was very striking," says Stockinger. "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 new research corresponds with a study from last year from Pennsylvania State University finding a broccoli-rich diet in mice improved gut flora and immune function. That study hypothesized the beneficial effects of broccoli as possibly due to an activation of AhR in the intestines. This new study only further adds weight to that hypothesis by targeting more directly the chemical mechanism that may be at play.

The new study of course doesn't specify what volume of vegetables is necessary for effective AhR stimulation. The Penn broccoli study last year worked with the equivalent of three and a half cups of broccoli per day, which to be honest, isn't a hugely realistic proposition for most people. It is also important to note that at this stage these results have only been shown in animal models, but Gitta Stockinger suggests it cannot hurt to add more vegetables to your diet.

"Now that we've demonstrated the mechanistic basis for this in mice, we're going to investigate these effects in human cells and people," says Stockinger. "In the meantime, there's certainly no harm in eating more vegetables!"

The new study was published in the journal Immunity.