Anemia interferes with the body’s ability to transfer oxygen through the tissues. This happens because, in this condition, one falls short of healthy red blood cells that carry oxygen. This leads to a lack of oxygen that can make one feel extremely tired. The condition can occur due to different reasons. Anemia is categorized into different types based on the causes.

Here are the four major types of anemia:

1. Iron deficiency anemia
When the body’s bone marrow isn’t supplied with adequate iron, it fails to produce enough hemoglobin. The lack of hemoglobin affects the red blood cells’ ability to supply oxygen, leading to anemia caused by iron deficiency. It can occur due to low iron intake or a certain illness that has reduced the body’s ability to absorb iron from the gastrointestinal system. At times, this type of anemia also occurs because of blood loss in excessive menstrual bleeding or internal bleeding.

2. Anemia of chronic disease
Anemia of chronic disease, also known as ACD, is a common type of anemia resulting from chronic illnesses. Patients with rheumatoid arthritis or lupus may develop anemia. Those with severe chronic infections, including HIV and viral infection, may get diagnosed with the condition. This occurs because these diseases create an unhealthy environment that doesn’t encourage ample oxygen supply. Cancer and Crohn’s disease can also cause anemia, as they affect red cell production.

3. Vitamin deficiency anemia
This type of anemia occurs when the body lacks two particular vitamins: vitamin B12 or cobalamin and vitamin B9 or folate. These vitamins are a prerequisite to the production of healthy red blood. When one doesn’t consume enough of these vitamins, their body cannot transfer oxygen easily. In some cases, however, one may develop vitamin deficiency anemia even after consuming vitamin B12. This happens when the body can’t process the vitamin in the first place. This condition is also called pernicious anemia.

4. Aplastic anemia
Aplastic anemia is a severe type of anemia that occurs when the bone marrow fails to function normally. It begins to produce very few red blood cells, which are not enough for a healthy oxygen transfer. One of the causes of bone marrow damage is exposure to intense beams during radiation therapy. Other cancer treatments like chemotherapy can also cause dysfunction of the bone marrow. Other causes include infection, contact with toxic materials, and autoimmune diseases. If anemia occurs due to one of these mentioned causes, it is known as acquired aplastic anemia. The other form is known as inherited aplastic anemia, which occurs due to a genetic defect.