Lettuce is an annual plant of the daisy family, Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, such as soups, sandwiches and wraps; it can also be grilled.
All types of lettuce are good and useful. As a vegetable, lettuce provides fiber, vitamins, minerals and phytochemicals for very, very few calories. With respect to vitamins, lettuce is a source of folate, a B vitamin needed to make and repair DNA in cells, and vitamin K, a nutrient linked to healthy bones.