Lettuce is one of the most widely consumed vegetables worldwide, but its nutritional value has been underestimated. Lettuce is low in calories, fat and sodium. It is a good source of fiber, iron, folate, and vitamin C. Lettuce is also a good source of various other health-beneficial bioactive compounds. Loaded with vitamins and minerals, eating a salad a day will also increase the level of powerful antioxidants in your blood. The basis of any salad, leafy greens, offer a huge nutritional benefit.