'Green leaf, red leaf, butterhead and iceberg are just a few common types of lettuce available at most markets. However, in terms of nutrient density, none are healthier than Romaine.
There are plenty of other green leafs which are even healthier such as spinach, kale, arugula, radicchio, endive etc, but for common lettuce types, romaine is king. Leafy greens in general are likely the number one food you can eat to regularly help improve your health.
If you start your meal with a salad made of romaine lettuce you will be sure to add not only a variety of textures and flavors to your meal but an enormous amount of nutritional value. Most of the domestic U.S. harvest of romaine lettuce and other salad greens comes from California and is available throughout the year.'