It turns out that green vegetables — from bok choy to broccoli — are the source of a chemical signal that is important to a fully functioning immune system. They do this by ensuring that immune cells in the gut and the skin known as intra-epithelial lymphocytes (IELs) function properly.
“It is still surprising to me,” said Marc Veldhoen of The Babraham Institute in Cambridge. “I would have expected cells at the surface would play some role in the interaction with the outside world, but such a clear cut interaction with the diet was unexpected. After feeding otherwise healthy mice a vegetable-poor diet for two to three weeks, I was amazed to see 70 to 80 percent of these protective cells disappeared.”