Spinach belongs to the same family as swiss chard and beets. Raw spinach has a mild, slightly sweet taste that can be refreshing in salads, while its flavor becomes more robust when it is cooked. Not only is spinach low in calories, it is also a good source of essential nutrients. One serving of spinach has 533 percent of the daily recommended amount of Vitamin A, 133 percent of the amount recommended for Vitamin C, 28 percent for calcium and 43 percent for iron.