S W A P

By Yossi & Malky Levine

A large, nutrient-dense salad is one of the smartest ways to go green. But when it comes to choosing the healthiest salad base, which types of lettuce pack the biggest nutritional punch? Not all leafy greens build a super-nutritious salad. America's favorite lettuce, iceberg, ranks the lowest in nutritional value across the board (96 percent water content does that!). Spinach leaves, on the other hand, boast nearly twice the recommended daily value of vitamin K, half the recommended value of vitamin A, and ample amounts of calcium and iron. Prefer a crunchier base? A cup of romaine is a tasty alternative, with a huge dose of vitamin A and a variety of other nutrients. Or, for a mild but textured bed, red leaf lettuce is just 4 calories per cup, with nearly half of the daily recommended dose of vitamins A and K.

As a general rule, darker loose lettuce and leaves contain more antioxidants and nutrients than the typically lighter-colored, more tightly-packed heads.