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. The vitamins, minerals, phytonutrients and fiber found in romaine lettuce are especially good for the prevention or alleviation of many common health complaints. As with other dark leafy greens, the antioxidants contained within romaine lettuce are believed to help prevent cancer.
Due to its extremely low calorie content and high water volume, romaine lettuce--while often overlooked in the nutrition world--is actually a very nutritious food. It is an excellent source of vitamin A (notably through its concentration of the pro-vitamin A carotenoid, beta-carotene), vitamin K, folate, and molybdenum. Romaine lettuce is also a very good source of dietary fiber, four minerals (manganese, potassium, copper, and iron), and three vitamins (biotin, vitamin B1, and vitamin C).
