Download File - Andrea Sigrist

Libby Macht
KNH 413
Spring 2013
Iron
1. What is the nutrient?
 Iron is a trace mineral needed in the diet. Heme iron is a component of
oxygen-carrying hemoglobin and myoglobin.1 Red pigment, or heme,
consists of 60% of the iron within the body.3 Non-heme iron is not part of
hemoglobin or myoglobin and is found in both animal- and plant-based
foods. Iron is also found in enzymes important for energy production and
is important part of immune funciton.1
2. What is the RDA/DRI for the nutrient?
 Infants: 0-6 months=0.27 mg; 7-12 months=11 mg
 Children: 1-3 years=7 mg; 4-8 years=10 mg
 Males: 9-13 years=8 mg; 14-18 years=11 mg; >18 years=8 mg
 Females: 9-13 years=8 mg; 14-18 years=15 mg; 19-50 years=18 mg; >50
years=8 mg
 Pregnancy: 27 mg
 Lactation: <18 years=10 mg; >18 years=9 mg1
3. How is the nutrient metabolized?
 Absorption: Heme iron is more readily absorbed. For example, 95% of the
iron in steak is absorbed whereas only 57% of the iron from fortified
bread is absorbed. Non-heme iron must first be reduced to the ferrous
state. This process can be aided by consuming food rich in vitamin C with
non-heme iron foods. Other aids to absorption include adequate HCl acid
in the stomach. Factors hindering iron absorption include oxalic acid, tea,
coffee, and smoking. Zinc is also an antagonist to iron.3
 Transport: Iron is absorbed into the blood and transported via
hemoglobin and myoglobin.1
 Storage: Hemoglobin contains 2/3 of all the iron in our bodies. Iron is also
stored in myoglobin.1 Excess iron can be found in the liver.2
 Excretion: The liver and spleen break down old red blood cells. Every day,
85% of iron released from hemoglobin breakdown is recycled in the
body.1
4. What are food sources of the nutrient?
 Food sources of heme iron include clams (14 mg/3 oz), steak (4 mg/4 oz),
and poultry (1 mg/3 oz). Food sources of non-heme iron include fortified
cereal (9mg/1 c.), spinach (6 mg/1 c.), kidney beans (5 mg/1 c.), tortillas
1 Thompson, J., & Manore, M. (2009). Nutrition: An applied approach (2nd ed.). San Francisco: Pearson Education.
2 Nelms, M., Sucher, K. P., Lacey, K., & Roth, S. L. (2011). Nutrition therapy & pathology (2nd ed.). Belmont: Wadsworth
Cewngage Learning.
3 Holford, P. (2004). The new optimum nutrition bible (2nd ed.). London: Crossing Press.
4 Iron and drug interaction details. (n.d.). Biologic Nutrigenomics. Retrieved April 22, 2013, from
http://www.biologicnr.com/database/data-results-herb.php?interact=iron&button2=Search
(2 mg/each), and baked potato with skin (2 mg/each).2 Other examples
include tomato paste (7 mg/c.) and boiled lentils (6.5 mg/c.).1
5. What disease states alter the nutrients metabolism?
 Alcoholism can alter the metabolism of iron, causing an excess or
deficiency in the body. Excess hepatic iron can cause further liver
damage.2
 Hemachromatosis is also known as iron overload. The body’s regulatory
mechanisms for iron are not functioning and iron is able to build up and
damage cells.2
6. What are the tests or procedures to assess the nutrient level in the body?
 Laboratory tests include determining values for hemoglobin (g/dL),
hematocrit (%), and serum ferritin/serum iron (ug/dL).2
7. What are the drug-nutrient interactions?
 Diuretics cause excess mineral loss in urine. Other examples of drugs that
interfere with iron absorption include antacids (decrease stomach HCl
acid), ACE inhibitor drugs, captopril, enalapril, H2 receptor blockers and
proton pump inhibitor drugs (alter GI pH), tetracycline drugs, and thyroid
medications.2,4
8. How is the nutrient measured?
 Iron in food is measured in milligrams and serum iron in the blood is
measured in micrograms.2
9. What is the Upper Tolerable Limit?
 The upper tolerable limit for iron is 40 mg/day for children under the age
of 14 and 45 mg/day for individuals 14 or older.2
10. What are the physical signs of deficiency?
 Symptoms include pale skin, sore tongue, fatigue, loss of appetite, and
nausea. Iron-deficiency microcytic or hypochromic anemia can be the
clinical manifestation of iron-deficiency.1,3
11. What are the physical signs of toxicity?
 Symptoms may include nausea, vomiting, diarrhea, dizziness, confusion,
rapid heartbeat, organ damage, and death.1 Chronic toxicity can lead to
functional diabetes, hepatomegaly, cicatrix formation, and cirrhosis.2
1 Thompson, J., & Manore, M. (2009). Nutrition: An applied approach (2nd ed.). San Francisco: Pearson Education.
2 Nelms, M., Sucher, K. P., Lacey, K., & Roth, S. L. (2011). Nutrition therapy & pathology (2nd ed.). Belmont: Wadsworth
Cewngage Learning.
3 Holford, P. (2004). The new optimum nutrition bible (2nd ed.). London: Crossing Press.
4 Iron and drug interaction details. (n.d.). Biologic Nutrigenomics. Retrieved April 22, 2013, from
http://www.biologicnr.com/database/data-results-herb.php?interact=iron&button2=Search