Anemia

Anemia may mean two things (or both):

• A decreased level of Hb (hemoglobin) in the blood, in absolute numbers. This may be because the level of Hb in the red blood cells is low, or because the level of red blood cells (which contain all the Hb in the blood) is low.
• A decreased capacity of each Hb molecule to bind oxygen, due to a deformity, nitrate exposure, or due to competitive gasses, such as carbon monoxide (from smoking, car exhaust or incomplete combustion), for example.

Hemoglobin

Hemoglobin (Hb) is an iron-containing protein in the blood. Hb transports oxygen (and some other (competitive) gasses, such as CO₂ and nitric oxide) to all your organs. Organs need oxygen to make use of nutrients (including energy) through oxidation. A lower level of Hb may therefore lead to a (relative) lack of oxygen in various organs (hypoxia).

Low Hb level

There are multiple possible causes for a low Hb level.

• Low serum iron (most commonly); if there is too little iron available, too little new Hb molecules are produced (as Hb contains iron).
• Nutritional deficiencies
• Mutations in one or more Hb genes, as in Thalassemia, sickle cell disease and hemolytic anemia.
• Blood loss
• Bone marrow issues
• Chemotherapy
• Kidney failure

Thalassemia

There are various types of thalassemia.

• beta-thalassemia; a hereditary trait particularly present in malaria-prone regions, as its relatively protective against malaria. In this trait, the production of protein for Hb is not properly regulated, and too little Hb A is produced. In Thalassemia the production (of ineffective-) and destruction of red blood cells is elevated (freeing up iron) and also gastrointestinal iron absorption is increased. This leads to the accumulation of iron in various organs, which may eventually cause liver cirrhosis or -fibrosis, heart failure, growth impairment, diabetes and osteoporosis. The severity of this disease depends on the nature of the mutation that causes it. Supplemental iron may have severe adverse effects. Besides serum iron (ferritin), in Thalassemia the level of Hb F may be elevated, and various red blood cell abnormalities may occur (small, low Hb relative to surface, pale, cells of unequal size, abnormally shaped, fragmented).