We died, NickW. And we're still dying from it. In the developing world, anemia is even more widespread due to parasites. They latch on in the intestines and suck the blood. Unfortunately, it causes babies to be born with lower intellectual capacities. And the women sometimes die. Really, really sad.
Anyhow, diet actually doesn't effect iron levels all that much. If your iron is low, either you are bleeding too much or you got unlucky with the genetics. Iron can't be left floating around in the body. It has to be carried around by proteins. If you inherit mostly crappy iron proteins, you're going to unfortunately need supplements. If you're really lucky and aren't bleeding, you can scavenge it out of anywhere. With that said, if you're anemic, you probably need to get the bleeding stopped (if you ARE bleeding) and take iron supplements. Diet can only fix very mild anemia.