Lack of Vitamin B12: symptoms, causes (and treatment)

A lack of vitamin B12 can cause symptoms such as tiredness, shortness of breath, tingling in the hands and pale skin. In children, a deficiency of this vitamin can cause delays in development and growth.

Vitamin B12, also known as cobalamin, is important for the development and maintenance of central nervous system functions, for maintaining heart health and for the formation of blood cells. Discover all the functions of B12 in the body.

In the presence of symptoms indicative of a lack of vitamin B12, it is advisable to consult a general practitioner or nutritionist, to identify the possible causes and initiate the most appropriate treatment, which may include injections, oral supplements and increased consumption of foods rich in vitamin B12.

Main symptoms

A lack of vitamin B12 can cause the following symptoms:

• Loss of sensitivity and tingling in the hands, legs or feet;
• Frequent fatigue and weakness;
• Palpitations;
• Shortness of breathe;
• Wounds in the mouth and tongue;
• Memory loss and mental confusion;
• Loss of appetite;
• Tremor in the eye.

In children, vitamin B12 deficiency can cause delays in growth and general development. Furthermore, a lack of this vitamin can also cause vision changes, irritability and megaloblastic anemia, a type of anemia where the bone marrow produces red blood cells that are larger than normal.

How to confirm vitamin B12 deficiency

Confirmation of vitamin B12 deficiency must be made by a general practitioner or nutritionist, through assessment of the symptoms presented, the person’s health history and eating habits.

If you want to confirm your risk of vitamin B12 deficiency, make an appointment with a general practitioner in your nearest region:

To confirm the diagnosis, the doctor also orders tests, such as a complete blood count, to evaluate the amount of red blood cells and hemoglobin in the blood, the levels of vitamin B12 in the blood, and endoscopy to evaluate possible causes of intestinal malabsorption, such as Crohn’s disease or celiac disease

Causes of lack of vitamin B12

A lack of vitamin B12 can have several causes, the main ones being:

• Low Vitamin B12 Intake: low intake of foods that are sources of or enriched with vitamin B12 can cause deficiency;
• Digestive diseases: diseases such as Crohn’s disease and celiac disease prevent the absorption of vitamin B12 efficiently;
• Bariatric surgery: depending on the type of bariatric surgery, the size of the stomach or intestine may be reduced, reducing the absorption of vitamin B12;
• Pernicious anemia: this type of anemia reduces the production of intrinsic factor, which is a protein necessary for the absorption of vitamin B12;
• Medication use: Some medications, such as proton pump inhibitors, H2 antihistamines, metformin or cholestyramine, can interfere with or reduce the absorption of vitamin B12.

Furthermore, excessive alcohol consumption and the use of medications such as antibiotics, metformin, omeprazole, esomeprazole and pantoprazole can also decrease the absorption of vitamin B12.

How the treatment is carried out

Treatment for a lack of vitamin B12 varies according to its cause and may include injections, supplementation and consumption of foods rich or fortified with this vitamin.

1. Vitamin B12 Injections

Intramuscular injections of vitamin B12, in the form of hydroxocobalamin, are indicated mainly in cases of lack of vitamin B12 caused by pernicious anemia, some types of bariatric surgery or eating styles with low consumption of this vitamin, such as a vegetarian diet.

The generally recommended dosage of intramuscular vitamin B12 is 1000 mcg, once a week, for four weeks, until the levels of this vitamin in the body are restored. After this period, the doctor may recommend the application of 1000 mcg of intramuscular vitamin B12, once a month. Learn more about vitamin B12 injection.

2. Supplements

In cases of vitamin B12 deficiency caused by low intake of this vitamin in the diet, the doctor or nutritionist may recommend oral vitamin B12 supplementation.

People with polycythemia, which is an increase in the number of red blood cells in the blood; allergic to cobalt or cobalamin, or who are in the post-operative period should only use vitamin B12 supplements under the guidance of a doctor.

3. Food

Increased consumption of foods rich or fortified with vitamin B12 is mainly recommended for people with low consumption of foods rich or fortified with this vitamin.

Therefore, the diet should include foods fortified with this vitamin and/or foods rich in vitamin B12, such as beef, fish, eggs and milk. See a list of foods rich in vitamin B12.