Fundamentals of Human Nutrition/Iron

< Fundamentals of Human Nutrition

11.1 IronEdit

Iron is a mineral found in every cell of the body and does many things in our bodies. Iron is an integral part of many proteins and enzymes that maintain good health. In humans, iron is an essential component of proteins involved in oxygen transport. For example, iron (as part of the protein hemoglobin) carries oxygen from our lungs throughout our bodies. It is also essential for the regulation of cell growth and differentiation. Almost two-thirds of iron in the body is found in hemoglobin, the protein in red blood cells that carries oxygen to tissues. Smaller amounts of iron are found in myoglobin, a protein that helps supply oxygen to muscle, and in enzymes that assist biochemical reactions. Iron is also found in proteins that store iron for future needs and that transport iron in blood. Iron stores are regulated by intestinal iron absorption.

11.1.1 SourcesEdit

Iron can be found in a wide range of food sources. There are two types of dietary iron sources, heme iron and nonheme iron. Heme iron is derived from hemoglobin, which makes up 40% of iron found in animal sources [1]. Heme iron is well absorbed. Examples of adequate animal source foods are red meats, fish, poultry, shellfish, and eggs. Liver, oysters, chickpeas, pumpkin seeds, soybeans and fortified cereals are especially bulky sources of dietary iron. Nonheme iron is derived from plant sources, making up 60% of iron found in plants and some animal tissues, such as in legumes, lentils, beans, spinach and dried fruits [2]. Our bodies less efficiently absorb nonheme iron but it makes up the majority of our dietary iron. George Mateljan says that plant source foods contain more than 10% of our daily iron requirement per serving [3]. This can be explained by the fact that plant source foods have fewer calories per serving and therefore have a higher density of nutrients per calorie. To assist our bodies in absorption of iron it is beneficial to eat an iron source along with a source of vitamin C. Adding 50 milligrams or more of vitamin to an iron-rich meal will make it possible to triple the absorption of dietary iron [4]. According to nutritionist, vitamin C has a stronger affect on nonheme iron than it does on heme iron. Many vegetables such as broccoli are high in both iron and vitamin C, thus allowing a hefty amount of iron to be absorbed. Certain foods and beverages can decrease iron absorption, for example tea and coffee.

11.1.2 FunctionsEdit

Iron is an essential nutrient because it is required to make hemoglobin and myoglobin, which are oxygen-carrying proteins in the body’s blood cells [5]. Hemoglobin is located in red blood cells, while myoglobin is located in muscles. About 70% of the bodies iron is found in hemoglobin and myoglobin [6]. Hemoglobin assist in the transfer of oxygen from the lungs to tissues located throughout the body. Iron is what creates the red color to our blood. Myoglobin receives, supplies, carries, and releases oxygen to our body muscles and the heart. Another function of iron is to make other body proteins, such as proteins essential for respiration and energy metabolism. Iron is also a component of enzymes that are involved in the synthesis of DNA, collagen, and certain neurotransmitters. Finally, iron contributes to proper immune function [7]. This function of iron is most important during childhood and pregnancy.

11.1.3 RequirementsEdit

11.1.4 DeficiencyEdit

Anemia is a common ailment characterized by a lack of healthy red blood cells. It also occurs when red blood cells in your body lack hemoglobin, a protein that enables the cells to carry sufficient oxygen to the tissues of the body (“What is Anemia,” 2012). Although the leading cause of anemia is blood loss, there are multiple types of anemia with various causes. This blood condition can be short term or long term and ranges from mild to severe (“Anemia,” 2014). Common causes of anemia are loss of blood, as mentioned before, low red blood cell production, and high amounts of red blood cells being destroyed. Loss of blood can be caused by heavy menstrual cycles, bleeding in digestive or urinary tracts, surgery, traumas, and even cancer. Furthermore, low red blood cell production can be the result of various factors. These factors include a diet with inadequate iron, low levels of the erythropoietin hormone, and certain chronic diseases, such as kidney disease. Finally, high rates of red blood cell destruction develop due to an enlarged or unhealthy spleen. Certain genetic characteristics may also cause your body to destroy an excessive amount of red blood cells like in the case of sickle cell anemia (“What is Anemia,” 2012). Certain individuals are at more risk of developing anemia than others. Some of these risk factors can be altered or changed, whereas others cannot. An example of a risk factor that can be altered is an iron-deficient diet. By increasing one’s intake of iron, the risk of developing anemia can be reduced. Risk factors that cannot be changed include blood loss from a surgery or trauma, pregnancy, and inherited anemia (“What is Anemia,” 2012). Various symptoms accompany anemia, the most common symptom being fatigue. Other symptoms of anemia include headaches, dizziness, cognitive complications, and shortness of breath. These symptoms may result due to the increased amount of work your heart is exerting in order to pump oxygen enriched blood throughout your body. Sometimes less severe forms of anemia may have mild or no symptoms (“Anemia,” 2014). The primary goal when treating anemia is to increase the red blood cell count in the body so that the blood can carry a much larger amount of oxygen (“What is Anemia,” 2012). Iron fortification or the defense of iron levels in the body is the primary way of both treating and preventing anemia. Individuals, especially pregnant and menstruating women must make the effort to increase their iron intake whether through use of supplements or changes in diet (Miller, 2013, p.8). Furthermore, medicines, surgeries, and procedures like blood transfusions and bone marrow transplants are alternate ways to treat anemia, particularly severe forms of anemia (“What is Anemia,” 2012).

References Anemia. (2014, August 19). Retrieved from What is Anemia? (2012, May 18). Retrieved from Miller, J. (2013, April 23). Iron Deficiency Anemia: A Common and Curable Disease. Retrieved from

11.1.5 ToxicityEdit

  1. Mangels, R. (2013, February 5). Iron in the Vegan Diet. Retrieved August 3, 2015, from
  2. Mangels, R. (2013, February 5). Iron in the Vegan Diet. Retrieved August 3, 2015, from
  3. Mateljan, G. (2001). Iron. Retrieved August 3, 2015, from
  4. Mateljan, G. (2001). Iron. Retrieved August 3, 2015, from
  5. Evert, A. (2013, February 18). Iron in Diet. Retrieved August 3, 2015, from
  6. UCSF Medical Center. (2002). Hemoglobin and Functions of Iron. Retrieved August 3, 2015, from
  7. Spatone. (2014). Role of Iron in the Body. Retrieved August 3, 2015, from