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Iron deficiency anemia

Iron is an essential mineral for synthesis of haemoglobin in the human body. Iron deficiency anemia occurs when this micronutrient intake is poor for prolonged period of time or its loss through bleeding loss.

Functions of iron in humans

  • Iron is one of the most abundant mineral on earth and it produces the commonest deficiency as well. Elemental iron occurs in two functional statuses inside the human body, ferric and ferrous.

  • Oxygen in the lungs capillaries attached to the heme-iron complex of haemoglobin in the red blood cells.

  • Oxygen is also bound by a heme-iron complex in muscle, myoglobin.

  • Iron is also a critical element in iron-containing enzymes, including the cytochrome system in the mitochondria. Without iron, cells lose their metabolic capacity. Thus, haemoglobin synthesis in the bone marrows erythroid cells is impaired, resulting in iron deficiency anemia and reduced oxygen carrying capacity and delivery to tissues.

Ferrous sulphate tablets to treat iron deficiency anemia
Ferrous sulphate tablets supplements to treat iron deficiency anemia.

Recommended daily intake-How much iron do you need in a day?

Out of total 4 gm iron in the human body, more than half distributed in red blood cells. In an adult male weighing 80 kg, about 2500 mg of iron is present in haemoglobin and about 500 mg in myoglobin. Any additional iron required for daily red cell production comes from the diet. Iron requirement increases during infancy, growing children and adolescents, pregnancy and lactation.

Category Age Group RDA
Infants 0-6 months 6 mg
6-12 months 10 mg
Children 1-10 years 10 mg
Males (younger) 11-18 years 12 mg
Males (older) 19 and above 10 mg
Females 11-50 years 15 mg
51 and above 10 mg
Pregnant woman 30 mg
Lactating Mother 15 mg

The RDAs for vegetarians are 1.8 times higher than for people who eat meat. This is because heme-iron from meat is more bioavailable than non-heme iron from plant-based foods, and meat, poultry, and seafood increase the absorption of non-heme iron.


What can cause low iron levels?

Iron deficiency is a status when total iron in the body depleted. This could be due either insufficient intake increased demand due to physiological states, worm infestations, excessive blood loss, and its poor absorption in the intestines.

Causes of poor intake and low absorption (bio-availability) of iron:

  1. In infants and young children, excess intake of cow's milk leads to iron deficiency anemia. Milk is a poor source of iron. Also, the very little iron present in the milk is poorly absorbed. Iron in the breast milk is more bio-available and absorbed than cow's milk.

  2. Illness of long duration like chronic renal disease, liver disease.

  3. Phytates and oxalates in cereals, high phosphates in cow's milk and excess zinc also reduce is absorption. Thus children who take only milk and plant produce tend to have iron deficiency anemia. On the other hand, acidic medium, vitamin-C and cobalt increase iron absorption.

  4. Consumption of coffee, tea, with food also reduces iron absorption and consumption of lemon juice, curd and fruit juice will increase absorption due to presence of vitamin C.

Iron deficiency anemia due to excessive loss of blood-

  1. Repeated blood donations,

  2. Excessive menstrual loss,

  3. Stomach ulcers, Gastro-intestinal bleeding conditions (eg. hemorrhoids),

  4. Blood loss Hookworm infestation.


Signs and symptoms of iron deficiency anemia?

Symptoms include-

  • Fatigue, tiredness, giddiness

  • Reduced exercise or work performance

  • Lack of concentration and poor memory

  • Persons of iron deficiency develop compulsive consumption to eat earth (geophagia), starch (amylophagia), and of ice or iced drinks (pagophagia).

Signs related to iron deficiency depend upon the severity and duration of the anemia in addition to the usual signs of anemia-

  • Paleness of mucus membranes (pallor)

  • Ulceration of mouth angles (angular cheiltis)

  • Spoon shaped finger nails (koilonychias)

  • Gradually, immune function and ability to fight against infections ensues when the deficiency becomes more pronounced.

Peripheral blood picture suggestive of smaller, paler red blood cells (microcytic hypochromic anemia), and in severe cases deformed blood cells.


Food sources of iron

Iron is present in green leafy vegetables, cereals, pulses, molasses, meat, egg, etc. Cooking in iron pots/skillet is also beneficial. When the percentage of iron absorbed from individual food items is compared with the percentage for an equivalent amount of ferrous salt, iron in vegetables is only about 5%, egg iron is 12%, liver iron 50%, and heme iron 50%-66%. Therefore, liver and heme iron absorbed nearly as well as iron salt added to food, while the iron in vegetables and eggs is much less available.

Iron from vegetables, fruits, and grains is harder for the body to absorb. Refer the table for food sources of heme iron and plant (non-heme) iron.

See the table below for in depth analysis:

Iron value per 100 g of food.

(Source: USDA National Nutrient database)
Food source Nutrient Value Percentage of RDA
Animal sources
Beef, lean meat 2.21 mg 28%
Bison, game meat 4.86 g 60%
Chicken 0.90 mg 11%
Egg, whole cooked 1.75 mg 22%
Lamb, lean meat 2.05 mg 26%
Milk 0.5 mg 6%
Seafood/Mollusk
Fish, trout 1.92 mg 24%
Mollusks, mussel 3.95 mg 49%
Octopus 5.3 mg 66%
Oyester 6.95 mg 87%
Plant sources
Fruits
Apricot, dehydrated 2.66 mg 33%
Currants, zante, dried 3.26 mg 41%
Raisins 1.88 mg 23.5%
Vegetables
Amaranth leaves, cooked 2.26 mg 28%
Beet greens, raw 2.57 mg 32%
Jute, potherb, cooked 3.14 mg 39%
Lima beans, immmature, boiled 2.45 mg 31%
Mushrooms, chanterelle, raw 3.47 mg 43%
Soybeens, green, raw 3.55 µg 44%
Spinach, raw 2.71 mg 34%
Nuts and seeds
Almonds, dry roasted 3.73 mg 47%
Hazelnuts 4.70 mg 59%
Pumpkin seeds, dried 8.82 mg 110%
Sunflower seeds, toasted 6.81 mg 85%

Iron Supplements

Iron fortified breakfast cereals, ferrous and ferric iron salts, such as ferrous sulfate, ferrous gluconate, ferric citrate and ferric sulphate.


Health risks from excessive iron

Excess iron intake for prolonged periods can cause overload disease known as hemochromatosis. In children with haemolytic anemia (thalassemia) who given repeated blood transfusion, iron deposition in liver, heart and brain resulting in hemosiderosis. Patients on iron toxicity should immediately seek help from physicians. (Medical disclaimer).



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Further reading and References:

  1. National Institute of Health-Iron Dietary Supplement Fact Sheet.

  2. U.S.National Library of Medicine-Iron in diet.

  3. USDA Food Composition Dtabases.



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