Lettuce is like conversation – it must be fresh and crisp, so sparkling that you scarcely notice the bitter in it. ~ American writer Charles Dudley Warner
The ancient Egyptians first cultivated lettuce, turning it from a weed – whose seeds were used to produce oil – into a plant grown for its seeds and leaves. Lettuce later spread to the Greeks and Romans, who used it medicinally, espeically to stimulate appetite or induce sleep.
The 16th–18th centuries witnessed a proliferation of lettuce varieties. By the end of the 20th century, lettuce was consumed worldwide. Lettuce has become the most popular leafy salad vegetable.
There are 5 types of lettuce: loose-leaf or simply leaf, romaine/cos, iceberg/crisphead, butterhead, and stem (aka asparagus lettuce). The most widely eaten, leaf lettuce produces crisp leaves arranged on a stalk. Romaine lettuce is excellent in salads and sandwiches, and is most often used in Caesar salads. Butterhead varieties, also known as Boston or Bibb lettuce, and in the UK as “round lettuce,” are generally small, with tender, soft leaves that have a delicate sweet flavor. Stem lettuce is grown for its seedstalk rather than its leaves and is mainly used in Asian dishes.
Iceberg is adapted to northern climates, and is most commonly grown commercially, though it requires the most care. Iceberg is the most popular lettuce in the US, despite having the least flavor and nutritional value owing to its high water content.
Except iceberg, lettuce leaves are a rich source of vitamins A and K, as well as providing calcium, iron, and copper. The leaf spine and ribs provide dietary fiber.