High doses of vitamin E can interfere with iron absorption. Excess iron can deplete phosphorus. Iron can accumulate to dangerous levels in patients with chonic kidney failure, Hodgkin's disease or rheumatoid arthritis. Prolonged use of high doses of iron can cause hemochromatosis and lead to diabetes, liver damage, impotence, heart problems and skin bronzing. Abdominal pain, black or gray stool, bloody stool, drowsiness, can stain teeth in liquid form, throat pain.
Iron increases the absorption of calcium and copper.
Vitamin C increases iron's effectiveness. Iron is necessary for the proper and efficient absorption of calcium and copper.