ABC News’ Carrie Gann reports:

Eager to fight colds and the flu this season? Try eating your veggies.

In a  study published today in the journal Cell, scientists found that green vegetables carry chemical signals that are essential to a fully-functioning immune system — in mice .

These signals help control the body’s first line of defense – a network of white blood cells called intra-epithelial lymphocytes — against infections and wounds.

Researchers at the Babraham Institute in Cambridge, England, fed mice different diets of vegetables and monitored the bacteria that accumulated in their guts. They found that mice that ate a diet low in green vegetables had more bacteria pile up than the mice that got plenty of veggies.

Marc Veldhoen, the lead author of the study, said the bacteria pile up because those mice are missing the crucial chemical found in green vegetables.

“If the mice do not eat their green, the immune cells in the intestine die,” he said. “That a dietary factor can so directly influence cells from the immune system did indeed come as a complete surprise to us.”

Mice that ate a vegetable-poor diet for two to three weeks had 70 to 80 percent of those cells disappear, leaving them more vulnerable to infections.

Although studies in mice don’t automatically apply to humans, Veldhoen said the mice he studied resemble patients who have  certain types of inflammatory bowel disease.

“Epidemiological studies have indicated a link with developing IBD and a diet poor in fruit and vegetables,” Veldhoen said. “How strong this link will be in controlled human trials, we will have to see.”