There is an illness which is reponsible for causing high iron levels in the blood (Hemochromatosis), but for those of us who just have "high" iron levels from inappropriate diet - it can be detrimental to health any way shape or form if it occurs over a number of years. High iron levels are associated with first time Stroke - as well as reoccuring strokes, and it has a very close nit connection with the disease Alzheimers. Lack of Iron can also have detrimental effects. Some people experience "Pica" or the eating of abnormal items to increase Iron levels. The body will begin craving things such as paper, ice chips or even dirt (children). Lack of Iron in the blood will cause Anemia - this means the oxygen your breath in can't bind at all or poorly to the hemoglobin (blood). When this occurs fatigue and a host of other symptoms can occur from the cells of your body starving. Oxygen is necessary for your cells to produce energy and survive. If anyone here has a low serum iron level and your doctor has prescribed iron supplements, then it's important to note that Iron is most absorbable in the ferrous form (fumarate or sulfate, less so in the gluconate form) than ferric. It is possible to suffer from both Iron Overload and Anemia at the same time - the cause of Anemia is not always a result of Iron Deficency. It's very complicated.