Green vegetables boost immunity

Green vegetables are the source of a chemical signal that is important to boost immunity, British researchers say. Marc Veldhoen of The Babraham Institute in Cambridge, England, said vegetables such broccoli or bok choy ensure immune cells in the gut and the skin known as intra-epithelial lymphocytes function properly. "It is still surprising to me," Veldhoen said in a statement. "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 percent to 80 percent of these protective cells disappeared." Those protective intra-epithelial lymphocytes exist as a network beneath the barrier of epithelial cells covering inner and outer body surfaces, where they are important as a first line of defense and in wound repair. Veldhoen's team found the numbers of intra-epithelial lymphocytes depend on levels of a cell-surface protein called the aryl hydrocarbon receptor, which can be regulated by dietary ingredients found primarily in cruciferous vegetables such as broccoli, brussels sprouts, cabbage or cauliflower. "It's tempting to extrapolate to humans," Veldhoen said. "But there are many other factors that might play a role -- but "it's already a good idea to eat your greens." The findings were published in the journal Cell.