I am not a vege but I believe iron is one of the major things you have to keep an eye on, the iron in meat is more easily absorbed than the iron in veg, though certain factors make veg iron more easily absorbed like Wednesday said.
Green leafy veg and dried pulses are the best sources for iron, lentils are marvellous, full of lots of good stuff.
http://www.vegsoc.org/info/iron.html http://www.vrg.org/nutrition/iron.htm