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Iron Functions, Sources and Deficiency symptoms

The total content of iron in an adult body is 3-5g. About 7o% of this occurs in the red blood cells as a constituent of hemoglobin. At least 5% of body iron is present in myoglobin of muscle. Heme is the most predominant iron containing substance. It is constituent of several proteins/enzymes- hemoglobin, myoglobin, cytochromes, xanthine oxidase, catalase, tryptophan pyrrolase, peroxidase. Certain other proteins contain non-heme iron- transferrin, ferritin and hemosiderin. Iron is an essential element for almost all living organisms as it participates in a wide variety of metabolic processes, including oxygen transport, deoxyribonucleic acid (DNA) synthesis, and electron transport.

Why is iron Important to the human body?

  1. Iron mainly exerts its functions through the compounds in which it is present. Hemoglobin and Myoglobin are required for the transport of oxygen and carbon di oxide.
  2. Cytochromes and certain non-heme proteins are necessary for electron transport chain and oxidative phosphorylation
  3. Iron is associated with effective immune-competence of the body

Iron absorption and metabolism:-

Iron is mainly absorbed in the stomach and duodenum. In normal people, about 10% of dietary iron is usually absorbed. Iron is mostly found in the foods in ferric form, bound to proteins or organic acids. Vitamin c is necessary to convert ferric iron to ferrous form. Iron in the ferrous form is soluble and readily absorbed. Iron is stored in liver, spleen and bone marrow in the form of ferritin. In the mucosal cells, ferritin is the temporary storage form of iron.

Iron metabolism is unique as it operates in a closed system. It is very efficiently utilized and reutilized by the body. Further, iron losses from the body are minimal which may occur through bile, sweat, hair loss etc. Iron is not excreted into urine. Thus, iron differs from the vitamins or other organic and inorganic substances which are either inactivated or excreted during the course of metabolic function. Iron entry into the body is controlled at the absorption level, depending upon body needs. Thus the periodical blood loss in menstruating women increases its requirements. Increased iron demands are alsoobserved in pregnancy, lactation and in growing children.

What are the food sources of Iron?

Dietary iron has two main forms: heme and nonheme. Plants and iron-fortified foods contain nonheme iron only, whereas meat, seafood, and poultry contain both heme and nonheme iron. High iron foods include clams, liver, sunflower seeds, nuts, beef, lamb, beans, whole grains, dark leafy greens (spinach), dark chocolate, and tofu.


irony iron


Rich sources:- organ meats such as liver, heart, kidney

Good sources:- leafy vegetables such as broccoli, Spinach, kale, collards, asparagus and dandelion greens. Pulses, cereals, fish, apples, dried fruits and molasses

Poor sources:- milk, wheat, polished rice


What is the recommended dietary allowance of Iron?

Age Male Female Pregnancy Lactation
Birth to 6 months 0.27 mg* 0.27 mg*
7–12 months 11 mg 11 mg
1–3 years 7 mg 7 mg
4–8 years 10 mg 10 mg
9–13 years 8 mg 8 mg
14–18 years 11 mg 15 mg 27 mg 10 mg
19–50 years 8 mg 18 mg 27 mg 9 mg
51+ years 8 mg 8 mg

Factors affecting Iron absorption

  1. Acidity, ascorbic acid and cysteine promot6e iron absorption
  2. In iron deficiency anemia, iron absorption is increased to 2-10 times that of normal
  3. Small peptides and amino acids favour iron uptake
  4. Phytate found in cereals and oxalate found in leafy vegetables interfere with iron absorption
  5. A diet with high phosphate content decreases iron absorption while low phosphate promotes
  6. Tea and eggs decrease iron absorption to a limited extent
  7. Iron absorption is diminished in copper deficiency
  8. Impaired absorption of iron is observed in malabsorption syndromes such as steatorrhea
  9. Administration of alkali decreases iron absorption
  10. In patients with partial or total surgical removal of stomach and/or intestine, iron absorption is severely impaired

What are the symptoms of iron deficiency?

  • Iron deficiency anemia:- this is the most prevalent nutritional disorder worldover, including the well developed countries. Several factors may contribute to iron deficiency anemia. These include inadequate intake or defective absorption of iron, chronic blood loss, repeated pregnancies and hookworm infections. Iron deficiency anemia mostly occurs in growing children, adolescent girls, pregnant and lactating women. It is characterized by microcytic hypochromic anemia with reduced blood hemoglobin levels. The other manifestations include apathy (dull and inactive), sluggish metabolic activities, retarded growth and loss of appetite

Initially, iron deficiency anemia can be so mild that it goes unnoticed. But as the body becomes more deficient in iron and anemia worsens, the signs and symptoms intensify.

Iron deficiency anemia symptoms may include:

  • Extreme fatigue
  • Pale skin
  • Weakness
  • Shortness of breath
  • Chest pain
  • Frequent infections
  • Headache
  • Dizziness or lightheadedness
  • Cold hands and feet
  • Inflammation or soreness of your tongue
  • Brittle nails
  • Fast heartbeat
  • Unusual cravings for non-nutritive substances, such as ice, dirt or starch
  • Poor appetite, especially in infants and children with iron deficiency anemia
  • An uncomfortable tingling or crawling feeling in your legs

 What is the effect of excessive iron in the body?

The excessive iron can cause hemosiderosis.

Hemosiderosis:- this is a less common disorder and is due to excessive iron in the body. It is commonly observed in subjects receiving repeated blood transfusions over the years. Iron is a one way compound, once it enters the body, it cannot escape. Excessive iron is deposited as ferritin and hemosiderin. Hemosiderosis is sometimes accompanied by hemochromatosis. Bronzed pigmentation of the skin, cirrhosis of liver and pancreatic fibrosis are the manifestations of the hemosiderosis. Hemochromatosis is a rare disease in which iron is directly deposited in the tissues such as liver, spleen, pancreas and skin. Hemochromatosis causes a condition known as bronze diabetes

What is the treatment for the iron deficiency anemia?

Initially, iron deficiency anemia can be so mild that it goes unnoticed. But as the body becomes more deficient in iron and anemia worsens, the signs and symptoms intensify. If you or your child develops signs and symptoms that suggest iron deficiency anemia, see your doctor. Iron deficiency anemia isn’t something to self-diagnose or treat. So see your doctor for a diagnosis rather than taking iron supplements on your own. Overloading the body with iron can be dangerous because excess iron accumulation can damage your liver and cause other complications. Oral ferrous iron salts are the most economical and effective medication for the treatment of iron deficiency anemia. Of the various iron salts available, ferrous sulfate is the one most commonly used.

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