6. Anemia due to decreased level of hemoglobin in red blood cells is generally observed due to deficiency of
   (1) Iron deficiency (2) Calcium deficiency
   (3) Vitamin B6 (4) Vitamin B12

Introduction

Anemia refers to a condition where there is a decrease in the number or quality of red blood cells, or more specifically the concentration of hemoglobin within them, leading to inadequate oxygen transport to the body’s tissues. Among the various causes of anemia, iron deficiency is the most common and significant cause of anemia due to its central role in hemoglobin synthesis. This article will explore why iron deficiency leads to anemia characterized by decreased levels of hemoglobin in red blood cells, distinguish it from other nutrient deficiencies such as calcium, vitamin B6, and vitamin B12, and discuss symptoms, causes, diagnosis, and treatment options.

Understanding Hemoglobin and Its Role

Hemoglobin is a complex protein found in red blood cells responsible for carrying oxygen from the lungs to body tissues and returning carbon dioxide for exhalation. Hemoglobin’s oxygen-carrying capacity is dependent on iron, which forms the core of the heme group where oxygen binds.

Without sufficient iron, the body can produce fewer or defective hemoglobin molecules, resulting in smaller or pale red blood cells that are less effective at oxygen transport, causing the classic symptoms of anemia.

Why Iron Deficiency Causes Anemia

Iron is an essential mineral required for making hemoglobin. Iron deficiency occurs when iron intake or absorption is inadequate, or iron loss exceeds intake, such as with chronic bleeding.

When iron stores are depleted, the bone marrow cannot produce adequate hemoglobin, leading to decreased hemoglobin concentration in red blood cells and ultimately a low red blood cell count.

This type of anemia is termed microcytic hypochromic anemia because red blood cells are smaller (microcytic) and contain less hemoglobin (hypochromic).

Symptoms of Iron Deficiency Anemia

Symptoms often develop gradually and may include:

• Fatigue and weakness due to poor oxygen delivery to tissues.

• Pale skin and mucous membranes.

• Shortness of breath, especially on exertion.

• Palpitations and rapid heartbeat.

• Dizziness or lightheadedness.

• Brittle nails and hair loss.

• Pica, an unusual craving for non-nutritive substances like ice or dirt.

• In children, irritability and poor growth may be noted.

Other Nutrient Deficiencies and Anemia

• Calcium deficiency (Option 2) does not cause anemia as calcium is not involved in hemoglobin synthesis or red blood cell production.

• Vitamin B6 deficiency (Option 3) can contribute to anemia but is relatively rare and usually results in sideroblastic anemia which is distinct in pathology.

• Vitamin B12 deficiency (Option 4) leads to megaloblastic anemia, characterized by large immature red blood cells, different from the decreased hemoglobin-driven anemia caused by iron deficiency.

Diagnosis

Anemia from iron deficiency is confirmed through blood tests such as:

• Complete blood count (CBC) showing low hemoglobin, hematocrit, and microcytic hypochromic red blood cells.

• Serum ferritin, serum iron, and transferrin saturation levels to evaluate iron stores.

• Peripheral blood smear to look for characteristic red blood cell changes.

• Additional tests may be necessary to determine the cause of iron deficiency, such as tests for gastrointestinal bleeding.

Treatment and Prevention

Treatment primarily involves iron supplementation, either oral or, in severe cases, intravenous. Addressing the underlying cause of iron loss, like controlling bleeding, is crucial.

Dietary sources rich in iron include red meat, beans, lentils, fortified cereals, and leafy green vegetables.

Prevention focuses on maintaining adequate iron intake and monitoring populations at risk, like pregnant women, children, and those with chronic blood loss or malabsorption conditions.