What causes anemia? (see the complete guide to the main causes)

Anemia is the decrease in the levels of hemoglobin in the blood, which is the protein located inside the red blood cells, responsible for carrying oxygen to the tissues.

It can arise from several causes, such as a diet low in vitamins, bleeding, malfunctioning of the bone marrow, autoimmune diseases or the existence of chronic diseases, such as arthritis or kidney failure, for example.

Anemia is detected through the blood count that identifies the hemoglobin levels in the blood, which, preferably, should be above 13 g% in men, 12 g% in women and 11 g% in pregnant women from the second trimester, because in this period the blood tends to become more diluted. Learn more about tests that confirm anemia.

Anemia can be mild or even profound, when the hemoglobin level is below 7g%, and this depends not only on the cause, but also on the severity of the disease and the response of each person's body.

Main causes of anemia

Some of the main causes of anemia include:

1. Vitamin deficiency

To properly produce red blood cells, the body needs essential nutrients. The lack of them causes the so-called deficiency anemias, which are;

• Anemia due to lack of iron in the body, called iron deficiency anemia, which can arise from a low iron diet, especially in childhood, or due to bleeding in the body, which may be imperceptible, such as a gastric ulcer or varicose veins in the intestine, for example.; Anemia due to lack of vitamin B12 and folic acid, called megaloblastic anemia, happens due to the low consumption of these substances in the diet. Vitamin B12 is consumed in meat or animal products, such as eggs, cheese and milk. Folic acid is found in meat, green vegetables, beans or grains, for example.

The absence of these nutrients is detected through blood tests ordered by the doctor. Usually, this type of anemia gradually gets worse, and as the body can adapt to the losses for some time, the symptoms may take time to appear.

Watch the video below and check out the guidelines of nutritionist Tatiana Zanin on what to eat in case of anemia:

2. Bone marrow defects

The bone marrow is where blood cells are produced, so if it is affected by any disease, it can compromise the formation of red blood cells and cause anemia.

This type of anemia, also called Aplastic anemia or Spinal anemia, can have several causes, which include genetic defects, intoxication by chemical agents such as solvents, bismuth, pesticides, tar, anticonvulsants, exposure to ionizing radiation, HIV infections, parvovirus B19, Epstein Barr virus or for diseases like paroxysmal hemoglobinuria notura, for example. However, in some rare cases, the cause may not be identified.

Read more about what it is and what to do in case of aplastic anemia.

3. Bleeding

Hemorrhages are serious as blood loss represents the loss of oxygen and nutrients to the body's organs.

Some of the most common causes of bleeding can be caused by injuries to the body, trauma due to accidents, very heavy menstruation or diseases such as cancer, liver disease, varicose veins or ulcers, for example.

In some cases, bleeding is not visible, requiring tests such as endoscopy or colonoscopy to identify. Know what can cause blood in your stool.

4. Genetic diseases

Hereditary diseases, which are passed through DNA, can cause changes in the production of hemoglobin, either in its quantity or in its quality. These changes usually result in the destruction of red blood cells.

The carrier of these genetic defects will not always present a worrying anemia, however, in some cases it can be severe and significantly compromise health. The main anemias of genetic origin are those that affect the structure of hemoglobin, also called hemoglobinopathies:

• Sickle cell anemia: it is a genetic and hereditary disease in which the body produces hemoglobins with altered structure, therefore, it originates defective red blood cells, which can take the form of a sickle, hindering its ability to carry oxygen in the blood. Check out the symptoms and treatment of sickle cell anemia. Thalassemia: it is also a genetic disease that causes changes in the proteins that form hemoglobin, forming altered red blood cells that are destroyed in the bloodstream. There are different types of thalassemia, with varying severities, learn more on how to identify thalassemia.

Although these are the best known, there are hundreds of other defects in hemoglobin that can result in anemia, such as methaemoglobinemia, unstable hemoglobins or hereditary persistence of fetal hemoglobin, for example, which are identified by genetic tests indicated by the hematologist.

5. Autoimmune diseases

Autoimmune hemolytic anemia (AHAI) is a disease of immunological cause, which arises when the body produces antibodies that attack the red blood cells themselves.

Although its exact causes are not yet known, it is known that they can be precipitated by other health conditions, such as viral infections, the presence of other immune diseases or tumors, for example. This type of anemia is not usually hereditary and is not transmissible from one person to another.

Treatment consists mainly of the use of medications to regulate the immune system, such as corticosteroids and immunosuppressants. Learn more about how to identify and treat autoimmune hemolytic anemia.

6. Chronic diseases

Chronic diseases, which are those that can last for many months or years in activity, such as tuberculosis, rheumatoid arthritis, rheumatic fever, osteomyelitis, Crohn's disease or multiple myeloma, for example, cause an inflammatory reaction in the body that can result in anemia, due to premature death and changes in the production of red blood cells.

In addition, illnesses that cause changes in hormones that stimulate red blood cell production can also be the cause of anemia, including hypothyroidism, reduced androgens or falling levels of the hormone erythropoietin, which may be reduced in kidney diseases.

This type of change does not usually cause severe anemia, and can be resolved by treating the illness that caused the anemia.

7. Other causes

Anemia can also arise due to infections, as in viral or bacterial infections, as well as it can arise due to the use of certain medications, such as anti-inflammatory drugs, antibiotics or anticoagulants, or by the action of substances such as excess alcohol or benzene, for example. example.

Pregnancy can cause anemia, basically due to weight gain and increased fluid in the circulation, which dilutes the blood. See also: Anemia in Pregnancy.

Causes of anemia in the elderly

The elderly are more likely to develop anemia, mainly due to changes in diet, which may be lacking in nutrients, as well as because chronic diseases are more common in the elderly and also the presence of bleeding due to digestive ulcers, intestinal varices or cancer, for example.

In addition, there are changes that take place in the body with advancing age, which include less bone marrow activity to produce red blood cells or more fragile blood cells.

Anemia symptoms

The symptoms that indicate anemia, vary with the type of anemia, but it is common to appear:

• Tiredness; Too much sleep; Pale skin; Lack of strength; Shortness of breath; Cold hands and feet.

In some cases, especially when it is caused by severe bleeding or when it is below 7g%, anemia can cause severe symptoms, such as pressure drop, rapid heartbeat or fainting, requiring rapid medical attention.

However, at an early stage, anemia can be mild and the individual does not notice the signs and symptoms, so only blood tests can confirm the presence of anemia. Read more about the symptoms at: Anemia symptoms.