Your body needs iron for the production of hemoglobin, the specialized protein that gives red blood cells their red color. Hemoglobin carries oxygen in the blood, making it vital to the function of all cells. A high level of iron in the blood can provoke the production of bioactive iron, which can promote oxidative stress. Oxidative stress contributes to atherosclerosis, a condition exacerbated by high cholesterol. In contrast, an iron deficiency does not contribute to cardiovascular problems, but the resulting medical condition of iron-deficiency anemia also causes symptoms.
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Damage from Iron
Your body functions through a series of continual biochemical reactions. Many of these reactions require oxygen. Some of the reactions involving oxygen produce a by-product called a free radical, also called a reactive oxygen species, or ROS. The presence of ROS molecules causes oxidative stress in your body, which promotes inflammation and causes cell damage. Research published in "BMC Medical Genomics" states that free iron molecules in the blood can react with proteins and unsaturated lipids, a type of fat, and promote the production of reactive oxygen species. In this way, too much iron in your body contributes to the process of atherosclerosis.
Oxidative stress and free radicals can damage the cells lining the blood vessels, inducing inflammation. The areas of damage attract the accumulation of fatty substances, cholesterol, calcium and other waste products in the blood. As these substances buildup, a process known as atherosclerosis, they form plaque. Plaque causes the walls of the blood vessels to become thick and hard, which restricts the flow of blood and can lead to heart disease – the leading cause of death in the United States. Because high levels of iron in the blood increase the amount of damage and high levels of cholesterol increase the rate of atherosclerosis, these two conditions should be avoided.
Cholesterol is a lipid, defined as a substance that cannot mix with water or blood, since blood consists mostly of water. Your body needs cholesterol to provide structure to cell membranes, promote the production of hormones and vitamins and produce bile acids necessary for the digestion of fats. Your liver cells produce most of the cholesterol in your body, but the food you eat can increase your cholesterol levels. To travel through the blood, cholesterol must bind to specialized proteins known as lipoproteins. Low-density lipoprotein, called LDL, binds to cholesterol in the liver and carries it through the blood vessels to the cells. If your blood contains too much cholesterol, defined as a total cholesterol level of 240 mg/dL or higher, your cells cannot use it all and it remains in the blood vessels. This allows more cholesterol to accumulate into plaque, thereby contributing to atherosclerosis. Doctors urge you to maintain your total cholesterol level at less than 200 mg/dL and your LDL cholesterol at less than 100 mg/dL.
Although too much iron in the blood can cause damage to the blood vessels, too little iron causes iron-deficiency anemia. Without enough iron, your body cannot produce hemoglobin. Without hemoglobin, the number of red blood cells decreases, causing a reduction in the amount of oxygen available to the cells. Iron-deficiency anemia causes fatigue, weakness, shortness of breath, dizziness and chest pain. To avoid either too much or too little iron, you should eat a healthy diet containing iron-rich foods like low-fat beef or poultry, fish, beans and lentils. This will help you meet the daily recommended intake of 8 mg per day for men and postmenopausal women and 18 mg per day for premenopausal women, set by the Institute of Medicine.
- “BMC Medical Genomics”; Iron Behaving Badly; Douglas Kell; January 2009
- “Journal of the American Society of Nephrology”; Intravenous Iron Exacerbates Oxidative DNA Damage; K. Kuo, et al.; September 2008
- American Heart Association: Atherosclerosis
- National Heart Lung and Blood Institute: Iron-Deficiency Anemia; April 2011
- National Institute of Health Office of Dietary Supplements: Iron; August 2007
- Institute of Medicine: Dietary Reference Intake Summary; 2005
- Linus Pauling Institute: Iron; Victoria Drake; August 2009