Have you ever wondered what the differences are? They are basically different varieties of the same lettuce. The biggest difference is the size or texture of the leaves. They can be used interchangeably in a recipe that calls for one of the three.
Per one cup they contain only 7 calories, 0 fat, 3 mg of Sodium(that's no much), and 1 gram of each-carbohydrate, fiber, sugar and protein.
They are high in Vitamin A (one cup gives you 36% of daily needs), Vitamin C and Iron.