Bok Choy...

This leafy green cabbage is the number one veggie in China and boasts 10 times the recommended amount of vitamin A in just one cup. Packed with antioxidants, it's no surprise that several studies show that high intake of Brassica vegetables (a family of vegetables including kale, broccoli, and bok choy) may reduce the risk of certain cancers, including prostate cancer.  I use bok choy in all my veggie stews!