Calories in Lettuce, iceberg

What makes lettuce so powerful?

Iceberg lettuce, originally known as crisphead lettuce, earned its modern name from the way it was transported in the early 20th century. Before refrigerated trucks existed, California growers shipped the lettuce cross-country to East Coast markets packed in crushed ice. The railcars looked like they were filled with icebergs, and the name stuck. Botanically, Iceberg is a variety of Lactuca sativa that forms a tight, cabbage-like head. Its signature crunch comes from the dense, blanched inner leaves, which are shielded from sunlight. Because sunlight cannot penetrate the outer layers, the inner leaves fail to produce chlorophyll, remaining pale white and developing a highly rigid cellular structure. While often dismissed as nutritionally void due to its 95 to 96 percent water content, a 100-gram serving actually provides a notable amount of vitamin K, essential for blood clotting and bone metabolism. The high water content, rather than being a drawback, makes it an exceptionally hydrating food, particularly useful in hot climates where maintaining fluid intake is difficult.