Every cell in the body needs iron. Many health conditions involve iron overload. Organs and body tissues store excess iron, which may associated with serious health complications and even death. Vitamin C works synergistically with iron absorption in the body. Long-term use of high doses of vitamin C may increase the risk of adverse effects in diseases such as hemochromatosis and thalassemia. Check with your health care provider before taking iron or vitamin C supplements; inform your doctor of all supplements you take.
In the U.S. 42 million people are at risk for iron toxicity, according to the Iron Overload Diseases Association. Low levels of iron protect against disease. The association reports high levels of iron disrupt the immune system, allowing for infection. High levels of iron can cross the blood-brain barrier, worsening problems such as Alzheimer's disease, multiple sclerosis, Lou Gehrig's disease, Parkinson's disease and psychological disorders, according to the association.
The body does not excrete excess iron. Donating blood provides a means of reducing iron levels. Ascorbic acid, in the natural state and in supplemental vitamin C, enhances iron absorption. Vitamin C doses in excess of 2,000 mg cause iron overload in the iron toxic disorder hemochromatosis and in thalassemia, a hemoglobin disorder, according to "Merck Manual."
Long exposure to high doses of vitamin C can cause iron toxicity and possible tissue damage in those with hereditary hemochromatosis, according to the The National Institutes of Health, Office of Dietary Supplements. This problem does not appear to occur in healthy people. The Food and Nutrition Board of the National Academies has identified an upper intake level of vitamin C of 2,000 mg for men and women 20 years of age and older.
The American Chemical Society reports the Landmark research by chemist J. L. Svirbely in 1937 led to the use of vitamin C as a treatment for scurvy, according to the American Chemical Society. In 1962 administration of vitamin C along with the drug desferrioxamine to remove iron overload in British children with thalassemia resulted in a two-fold increase in iron, according to Northern California Thalassemia Center. Trials continued into the 1970s to determine what amounts of drugs and vitamin C were appropriate. During these trials, 500 mg of vitamin C taken with these drugs caused a decrease in cardiac function, according to the center. Discontinuing use of vitamin C returned cardiac performance to normal.
The U.S. National Library of Medicine reports vitamin C has significant action on iron storage in the body. Studies of iron metabolism at the cellular level, enhanced with the ascorbate form of vitamin C, showed that vitamin C not only increased iron amounts but also prevented the loss of iron.