Vitamin B12 and folate deficiency anemia



Anemia is a blood disease characterized by below-normal values ​​of a protein contained within red blood cells, hemoglobin, which has the task of transporting oxygen from the blood to all body tissues. According to the World Health Organization, anemia is ascertained (diagnosed) when hemoglobin values ​​are less than 12 grams per deciliter (g / dL) in women and 13.4 g / dL in men.

The causes that can generate anemia are various (Video), among the most common are iron deficiency (iron deficiency anemia), deficiency of B vitamins (megaloblastic and pernicious anemia), some chronic and infectious diseases, autoimmune diseases (haemolytic anemia), bone marrow dysfunctions, pregnancy, the use of certain drugs and hereditary diseases such as thalassemia (Mediterranean anemia).

Larger than normal red blood cells are produced in the body (deficiency) of vitamin B12 (cobalamin) and / or folate (vitamin B9) which do not function properly and therefore cause anemia.


Vitamin B12 or folate deficiency anemia can cause a wide range of disorders (symptoms).They usually develop gradually but can get worse if the anemia is not treated.

They include:

  • fatigue and exhaustion even at rest (asthenia)
  • respiratory difficulties (dyspnoea) even in the absence of physical exercise
  • headache (headaches and migraines) frequent and prolonged
  • pale skin and mucous membranes
  • increased number of heart beats (tachycardia)
  • disturbances of balance and decreased mental faculties such as, for example, difficulties with concentration and memory
  • lack of appetite and weight loss

If anemia is caused by a lack of vitamin B12, the following can also occur:

  • vision disturbances
  • yellow skin tone (jaundice)
  • inflammation and swelling of the tongue (glossitis)
  • tingling in the limbs (paraesthesia)

Some of these disorders (symptoms) can also occur in people who have a B12 deficiency but have not yet developed anemia.

In case of anemia caused by a lack of folate (vitamin B9), the following may appear:

  • reduced sense of taste
  • diarrhea
  • muscle weakness
  • depression

If these disorders (symptoms) occur, it is advisable to consult the family doctor who, in addition to carrying out a general examination, may prescribe some blood tests necessary to ascertain the causes and identify the most effective treatment. Although it is a well treatable disease, the neurological alterations it causes, if not treated as quickly as possible (early), could become irreversible and permanent.


Vitamin B12 or folate deficiency anemia occurs when a lack of one or both of these vitamins affects the body's ability to produce fully functional red blood cells. In fact, most people affected by this form of anemia have red blood cells that are not properly developed and larger than normal, a condition called megaloblastic anemia.

Causes of Vitamin B12 Deficiency

Possible causes of vitamin B12 deficiency include:

  • pernicious anemia, autoimmune disease affecting the stomach. It occurs because the body's defense system (immune system), instead of attacking germs and foreign substances that enter the body, as it normally does, mistakenly attacks the body's healthy cells. Normally, in the stomach, vitamin B12 binds to a protein, called intrinsic factor due to its constant presence in the body, necessary for the absorption of the vitamin in the intestine. In pernicious anemia, the immune system attacks the stomach cells that produce intrinsic factor and, consequently, the body is no longer able to absorb vitamin B12. The exact cause of pernicious anemia is unknown: the disease occurs more in women around 60 years of age, in people who have family members already affected by the disease (family history) or in individuals with an autoimmune disease known as Addison's disease
  • nutritional deficiencies, some people may have a deficiency of vitamin B12 due to its poor introduction in the diet. A diet that includes meat, fish and dairy products generally provides enough vitamin B12 but people who do not consume these foods regularly like, for example , those who follow a vegan or vegetarian diet, or who eat too little, may suffer from a deficiency. There are, however, also alternative foods that contain vitamin B12 such as, for example, yeast extract, some cereals from breakfast and soy products. On the nutritional labels on the external packaging of the products it is possible to check the quantity of vitamin B12 contained in the food. The body's reserves of vitamin B12 can last from about two to four years if they are not replenished.Therefore, it could take a long time before the anemia manifests itself
  • gastro-intestinal diseases, some diseases of the stomach (gastritis, ulcer), of the intestine (Crohn's disease) or surgery involving these organs can prevent the absorption of vitamin B12 and, therefore, increase the risk of developing a deficiency
  • interaction with certain medications, some types of medicines can cause a reduction in the amount of vitamin B12 absorbed. Proton pump inhibitors (PPIs), drugs used to treat gastritis and ulcers, for example, limit the production of gastric juices which, however, are necessary to extract vitamin B12 from the foods eaten. This results in a drastic decrease. the amount of vitamin B12 absorbed
  • deficiency of functional vitamin B12, it occurs due to problems in proteins that carry vitamin B12 into cells. This type of deficiency can also lead to neurological complications

Causes of folate deficiency

Folate are chemical compounds that dissolve in water (soluble). Consequently, the organism is not able to store the absorbed folates for long periods of time. The physiological reserves usually last about four months and it is therefore necessary to introduce folate with the daily diet to ensure that reserves are always available.

Lack of folate can be caused by:

  • nutritional deficiencies, folates are present in many common foods (different types of vegetables and legumes, brown rice), consequently one of the main causes of their deficiency lies in an unbalanced diet. Since their absorption is also strongly compromised by alcohol, it follows that even people who abuse alcoholic beverages are at high risk of developing this form of anemia.
  • malabsorption, some diseases, such as celiac disease which affects the intestinal mucous membranes, are at the basis of a reduced or absent absorption of folate from food. Also urinating often (polyuria) can lead to an excessive loss of folate. This disorder can be caused by:
    • congestive heart failure, a disease in which the heart cannot pump enough blood around the body
    • acute liver damage, often caused by consuming excessive amounts of alcohol
    • long-term dialysis, a procedure in which a machine performs the function of the kidneys and filters the blood to eliminate waste products in people with kidney failure
  • interaction with certain medications, some types of medicines can reduce the amount of folate in the body, making it difficult to absorb. Among these, some anti-convulsant drugs used in the treatment of epilepsy such as, for example, cholestyramine, sulfasalazine and methotrexate
  • other causes, sometimes the body requires more folate than normal and this can cause its lack if it is not possible to meet the needs by introducing a sufficient quantity with the diet

Among the conditions that require a greater availability of folate, the most common is pregnancy: in case you are planning to have a baby, or if you are already pregnant, it is advisable to take folic acid every day until the 12th week of gestation, in order to provide the unborn child with the amount of folate necessary for the proper development of its nervous system.

Premature babies (born before 37 weeks of pregnancy) are more likely to have folate deficiency because their bodies require more folate than full-term babies.


The "detection (diagnosis) of vitamin B12 and folate deficiency anemia is based on the execution of some blood tests including the"blood count, also said blood count. It allows to evaluate both the hemoglobin level (Hb) which, as in any form of anemia, is decreased, and the mean corpuscular volume (MCV) which, usually, is increased.

The blood count must always be accompanied by a microscopic examination of the blood smear useful to confirm the presence of red blood cells larger than normal (macrocytes), and less colored (hypochromia), and to reveal the presence of other cellular alterations such as, for example, the presence of white blood cells with hypersegmented nucleus and platelets with increased size.

Furthermore, with blood tests, increased values ​​of bilirubin, ferritin and lactic dehydrogenase caused by ineffective production of red blood cells can be discovered.

Other blood tests useful to ascertain the disease are the deoxyuridine conversion test, the methylmalonic acid and homocysteine ​​dosages - which, however, may not show abnormalities until the person becomes anemic - and, above all , the dosage of vitamin B12 and the dosage of folic acid.

The value of vitamin B12, however, may not be completely conclusive because some individuals experience disorders related to anemia even in the presence of normal levels of the vitamin or, on the contrary, do not experience any disturbance (symptoms) despite the dosage being lower than normal. .

Such discrepancies are possible because the blood test only measures the total amount of circulating vitamin B12, but cannot distinguish the active form, the one that the body is actually able to use, from the inactive form. Therefore, the results of the vitamin B12 dosage could show normal values ​​even if the vitamin present is in an inactive form and therefore not usable by the body.

If the doctor, after having listened to the story of the disorders (symptoms), having performed the visit and evaluated the results of the analyzes, should suspect the presence of a "pernicious anemia, he could prescribe tests to verify whether the lack of absorption of the vitamin B12 taken with nutrition may be due to an autoimmune disease. In particular, it will be necessary to look for any circulating autoantibodies and evaluate their quantity and type in order to confirm the diagnosis and immediately begin the most appropriate treatment.


Most people with vitamin B12 and folate deficiency anemia can be easily treated with therapies that contain the missing vitamins, to be taken by mouth (orally) or by injection (intramuscular), and by including them in the daily diet. foods that are rich in it.

Those who follow a "vegan diet, on the other hand, will need to take vitamin B12 supplements for life."

It must be remembered that this type of treatment alone can correct the anemia but cannot reverse neurological damage.

To check the effectiveness of the treatment (therapy) it will be necessary to carry out blood tests at periodic intervals and to check above all the hemoglobin levels and the number of reticulocytes (immature red blood cells present in the circulating blood).


NHS. Vitamin B12 or folate deficiency anaemia (English)

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