I have too have read that iceburg lettuce is nutritionally inferior to other types of lettuce such as romaine. Got out my handy dandy book and this is why. Romaine lettuce is greener than iceburg lettuce and has about three times as much vitamin C and six times as much vitamin A as iceburg lettuce. Iceburg lettuce is mostly water and its light green colour makes it weak nutritionally, The darker green your lettuce is, the better it is for you. By the way,this goes for all vegetables- the more highly coloured your veggies are, the more better they are for your body nutritionally. For example, cucumber's do not have many nutrients, but they are full of water and may help you feel fuller. Fresh iceburg lettuce has a high water content too and is low in calories. This is why so many people use it in their diet plan, but its not a good a idea to rely exclusively on this type of lettuce for your salads-you will be short changing yourself nutritionally.
The vitamin K in leafy greens helps the body make a protein that is vital for bone health. Dark green colour Leaf lettuce is high in vitamin A supplying 40 % of your daily needs. Vitamin A is important for good eye health and helps the body fight infection. Romaine lettuce is also an excellent source of vitamine A and contains folate.
Phytochemicals in Romaine lettuce that are thought to reduce the incidence of Cancer include lutein and coumarins. So, skip the iceburg lettuce if your concerned with optimum nutritional value for your hard earned dollar and go buy yourself these lettuces: Romaine. Boston/Bibb/ butterhead. And Green leaf. Also, don't forget about all your other green vegetables such as Swiss chard. (Yummy sauteed)
Another thing about iceburg lettuce- you are not even supposed to exclusively feed your hamster iceburg lettuce! (my daughter just told me this)