Calcium is a very important nutrient that helps in improving the health of bones and teeth. We all know that dairy foods like milk and yogurt are the best sources of calcium. Some people cannot tolerate the dairy foods due to the lactose present in it. You may be surprised to know that some non-dairy foods also contain calcium. We will discuss about these food sources here. Collard greens are a green leafy vegetable that is a rich source of calcium. Broccoli, kale and bok choy are the other foods. You should include these foods in your diet. Following are the 18 surprising dairy free sources of calcium.