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Iron-deficiency Anemia

Iron-deficiency Anemia
portrait of José Antonio Zumalacárregui Ph.D.
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José Antonio Zumalacárregui Ph.D.
Medically reviewed by our Medical staff

Last update: 21-06-2021

How else can it be called?

  • Iron-deficiency anaemia

  • ICD-10: D50

What is iron-deficiency anemia?

Iron-deficiency anemia is a disorder in which the body synthesis of red blood cells (RBCs) is limited due to a lack of iron.

Red blood cells (RBCs), also called erythrocytes, carry oxygen (energy) to the different cells of the body, and eliminate the excess of carbon dioxide (waste product).

To carry out this function, red blood cells use a protein called hemoglobin. Iron is one of the chemical elements that make up hemoglobin; therefore, iron is an essential mineral used by RBCs (Red Blood Cells) to correctly carry oxygen to the cells and take back carbon dioxide.

The state in which there is a hemoglobin deficit is called anemia. There are different causes for a lack of hemoglobin in the body, resulting in different types of anemia (hemolytic anemia, sideroblastic anemia, etc.).

Iron-deficiency anemia is one of them and occurs due to the lack of iron that prevents hemoglobin from being adequately synthesized. Iron-deficiency anemia is the most common type of anemia.

What causes iron-deficiency anemia?

As previously mentioned, the main cause of iron-deficiency anemia is the lack of iron stores in the body that consequently result in red blood cell synthesis impairment.

The lack of iron can be due to two main factors:

  • Deficient intake of iron in the diet and/or impaired absorption of the mineral.
  • Loss of blood (causing loss of iron with it).

The loss of blood, even when it goes unnoticed, is without any doubt the most influential factor in iron-deficiency anemia, and can be caused by multiple reasons (menstruation, blood in stool, hemorrhages, etc.).

Red blood cells have a life span of 120 days approximately and then they are broken down. The iron that they contained is then excreted through the urine after biotransformation. Overall, it is estimated that there is a daily elimination of iron of about 1 to 2 mg that must be compensated through diet.

Iron-deficiency anemia is a disorder that mainly affects women since the normal loss of iron through the urine is combined with the loss of iron during the menstruation. For that reason, it is important to have stores of iron in the body to compensate this loss.

It is estimated that between 2 and 5% of women of childbearing age have iron-deficiency anemia.

The most common causes that may lead to iron-deficiency anemia are:

  • Low protein diet (e.g. vegetarian diet)
  • Hypermenorrhea (profuse menstrual flow)
  • Gastrointestinal bleeding (ulcers, esophageal varices)
  • Malabsorption (Celiac disease, Crohn's disease)
  • Blood donations
  • Bariatric surgery that may reduce iron absorption (gastric resection, etc.)
  • Intestinal parasites (Necator americanus, Ancylostoma duodenale, etc.)

What are the main symptoms for iron-deficiency anemia?

Moderate anemia may cause symptoms such as:

  • Fatigue
  • Headache
  • Dyspnea (shortness of breath)
  • Irritability

If the lack of iron progresses even more, and suppose a serious depletion of oxygen transportation to the cells, the next symptoms may be seen:

  • Dizziness
  • Faint
  • Pallor
  • Palpitations
  • Difficulty or inability to carry out daily physical activities

A severe iron-deficiency anemia not properly treated may lead to heart failure.

How is iron-deficiency anemia detected?

The best way to detect this type of anemia, apart from the related symptoms, is by a blood test.

In case of anemia, hemoglobin levels are always below normal rate: below 13 g/dl in men, below 12 g/dl in women, and below 11 g/dl in children between 6 months and 6 years of age.

In addition to low hemoglobin levels, the blood test might also show:

  • Low hematocrit levels
  • Low MCV (Mean Corpuscular Volume or microcytosis): less than 80 fl
  • Low MCHC (Mean Corpuscular Hemoglobin Concentration or hypochromia): less than 32 g/dl
  • Low MCH (Mean Hemoglobin Concentration): less than 27 pg
  • High RDW (Red Cell Distribution Width)

According to these results, iron-deficiency anemia can also be classified as microcytic and hypochromic anemia.

Additionally, since there are low iron stores in the body, ferritin will also be decreased below 10 ng/ml (sometimes with levels close to 0).

If there are high levels of eosinophils (eosinophilia), it can suggest that the cause of the anemia is parasitic.

What is the recommended treatment?

Iron-deficiency anemia is treated with iron supplements such as ferrous sulfate orally at doses of 400 to 600 mg daily. This treatment can increase hemoglobin levels by 1-2% after 6 days.

Other supplements that can be used are:

  • Ferrous fumarate
  • Carbonyl Iron

In severe cases, when there is a continuous loss of blood or absorption impairment from the gastrointestinal tract, iron can be given intravenously (iron dextran).

How can I prevent iron-deficiency anemia?

To avoid iron-deficiency anemia, an adequate intake of iron in the diet is necessary. Top iron-rich foods include:

  • Meat: beef, chicken, turkey or pork (liver, kidneys, brain and heart).
  • Nuts: pistachios, almonds, walnuts.
  • Vegetables: spinach, kale and Swiss chard.
  • Shellfish: clams and cockles.
  • Legumes: lentils, beans or chickpeas.

In breastfeeding children, breast milk does not contain enough iron for the child. For that reason, sometimes is necessary to use iron supplements.

Medically reviewed by our Medical staff on 21-06-2021


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