The human body needs iron for the production of proteins and enzymes. In fact, the National Institutes of Health Office of Dietary Supplements reports that approximately two-thirds of all the iron in the body can be found in hemoglobin, the protein in red blood cells that carries oxygen. Although necessary, getting too much iron can contribute to medical problems and even lead to poisoning. A scientist named Jerome Sullivan raised the question about whether too much iron increases the risk for developing heart disease.
Iron Storage
Although you need to consume the recommended daily intake of iron each day, as outlined by the National Institutes of Medicine Food and Nutrition Board, your body retains and reuses approximately 90 percent of its iron each day. The protein known as ferritin binds to and stores iron. Ferritin can then release iron as the body needs it to help protect against iron deficiency. In addition, as the blood gets too much iron, ferritin can store more of the iron to protect against serum overload. It is the increased stores of iron that may contribute to heart disease.
Measuring Iron
When doctors suspect an iron overload, they can run various tests on the blood to measure the amount of iron in the body. Serum iron tests indicate the amount of iron in the blood while a ferritin test reveals the amount of iron bound to ferritin. A total iron binding capacity test, called a TIBC, when used with the serum iron test can help doctors calculate the amount of transferrin -- the protein that binds iron to transport it in the blood -- saturated with iron. All these tests together help determine the presence of an overload and any increased risk for heart disease.
Women and Heart Disease
One of the main factors that initiated the hypothesis that iron stores contribute to heart disease is the fact that pre-menopausal women possess a lower risk of heart disease than either men or post-menopausal women, as described by the National Institutes of Health Office of Dietary Supplements. Because pre-menopausal women generally have lower levels of iron, due to losing iron each month during menstruation, researchers believed it may contribute to their lower incidence of heart disease.
Blood Donation
To further test this theory, several groups of scientists, as outlined in the research published by Christopher Sempos in the September 2002 issue of "The American Journal of Clinical Nutrition," performed studies on groups of people to determine if those who frequently donate blood develop heart disease less often. Because donating blood decreases iron stores, it may be a way to safely decrease your risk for heart disease. However, these studies contained flaws because the subjects had other risk factors for heart disease or already suffered from heart disease.
More Research Needed
To date, the question of whether iron plays a role in heart disease cannot yet be fully answered. Does iron stimulate the activity of free radicals -- negatively charged particles in the body that can then damage the blood vessels and lead to heart disease? The studies published so far provide weak and inconclusive evidence, often with conflicting results on the correlation, according to "The American Journal of Clinical Nutrition." More research needs to be conducted to provide solid evidence.
References
- National Institutes of Health Office of Dietary Supplements: Iron
- National Institute of Medicine Food and Nutrition Board: Dietary Reference Intakes
- "American Journal of Clinical Nutrition"; "Do Body Iron Stores Increase the Risk of Developing Coronary Artery Disease?"; Christopher Sempos; September 2002
