Vitamin B12 Deficiency: Symptoms, Causes, and Treatment

May 9, 2024

Vitamin B12 Deficiency: Symptoms, Causes, and Treatment
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A water-soluble vitamin B12 (cobalamin) is essential for many body processes. The body needs this vital component, which it cannot create on its own, thus it must be received through food or supplements.

The major functions of vitamin B12 are the synthesis of red blood cells, the upkeep of a healthy neurological system, and the metabolism of fats and proteins. In addition, it helps maintain brain function and aids in the creation of DNA. The improper absorption of this vitamin can lead to the body showing B12 deficiency symptoms.

What is Vitamin B12?

A vitamin that acts as the support system for the blood and nervous system is vitamin B12. Furthermore, it equally serves the purpose of producing DNA, a very crucial molecule that makes up every cell of the body. Consuming food and beverages containing vitamin B12 fluids is advisable because the body is unable to produce vitamin B12 naturally. Animal products and drinks like meat, dairy, and eggs are one of the many foods that contain vitamin B12. Additionally, foods that have certain vitamins and minerals added to them, such as bread, nutritional yeast, and some cereals, are also fortified with it.

Vitamin B12 Deficiency

The synthesis of DNA, the building block of all cells, and the maintenance of nerve and red blood cells depend on vitamin B12. It also supports the neurological system.

If the body is not correctly absorbing vitamin B12 or not getting enough of it through the diet, chances of developing a curable vitamin B12 deficiency are high. Anaemia and damage to the brain and nerves can result from a vitamin B12 shortage if left untreated. Depression, constipation, and weakness are some of the early signs. Brain and nerve injury are other possible outcomes. Long-term harm might be irreparable, The usage of certain medications, food considerations, and underlying medical issues can all contribute to it.

Causes of Vitamin B12 Deficiency

A vitamin B12 shortage results from either consuming insufficient amounts of vitamin B12 or the body not correctly absorbing the vitamin B12. The following circumstances or ailments are the causes of vitamin B12 deficiency:

    • Dietary deficiencies in vitamin B12: Individuals who do not consume enough naturally occurring vitamin B12-containing foods or foods fortified with B12 may show B12 deficiency symptoms.
    • Gastritis: This condition is characterised by inflammation of the stomach lining. It can result in vitamin B12 deficiency because the stomach does not produce enough hydrochloric acid, which is necessary for the absorption of vitamin B12.
    • Pernicious Anaemia: This uncommon disease prevents people from producing protein in the stomach. The body cannot absorb the vitamin B12 without its inherent component. A vitamin B12 deficiency is seen in those who have pernicious anaemia.
    • Digestive disorders: Conditions affecting the digestive tract, such as Celiac disease and Crohn’s disease, may hinder how the body absorbs vitamin B12.
    • Surgery: Patients who have undergone gastrointestinal surgery, such as a gastric bypass (a procedure used to lose weight), may find it difficult to absorb vitamin B12.
    • Alcohol consumption disorder: This disorder can harm the digestive tract resulting in a vitamin B12 deficiency.
    • Transcobalamin II deficiency: A rare hereditary condition that affects how well vitamin B12 (cobalamin), is transported into the body
    • Vitiligo
  • Certain medications

Vitamin B12 Deficiency Symptoms

Fatigue, sluggishness, depression, dyspnea, and nerve issues are some of the B12 deficiency symptoms. Some of the other symptoms are:

  • Breathlessness: Breathlessness can also be a symptom of anaemia caused by a vitamin B12 deficiency. This has to do with a rapid pulse and a deficiency of red blood cells.
  • Elevated heart rate: One sign of vitamin B12 insufficiency might be a rapid heartbeat. To compensate for the body’s decreased red blood cell count, the heart may begin to beat more quickly. 
  • Tingling: A lack of vitamin B12 may result in a tingling feeling in the hands or feet. Vitamin B12 aids in the production of myelin, a material that coats and facilitates the transmission of feelings along neurons. Insufficient myelin makes nerves more vulnerable to injury. Peripheral nerves, or those in the hands and feet, are more prone to problems. Tingling in these body areas may be caused by injury to the peripheral nerves.
  • Pale complexion: Jaundice, or pale and yellowing skin, can result from a vitamin B12 shortage. Insufficient production of red blood cells (RBCs) by the body might lead to these skin colour alterations.
  • Difficulties with walking: Damage to the peripheral nerves over time may result in issues with mobility, numbness in their feet and limbs, weaker muscles, and slower reflexes. 
    • Exhaustion: Fatigue may result from megaloblastic anaemia caused by a vitamin B12 deficiency. An individual may feel very exhausted if the body does not have enough red blood cells (RBCs) to distribute oxygen.
  • Mouth-ache: The following oral issues can result from a vitamin B12 deficiency and impact oral health:
  1. Glossitis, resulting in a smooth, red, swollen tongue
  2. An unpleasant aftertaste
  3. A burning feeling in the tongue

Less oxygen reaches the tongue as a result of decreased red blood cell production,  which causes these symptoms.

    • Issues with logic or thinking: Cognitive impairment is the term used by doctors to describe thinking difficulties and memory loss that may result from a vitamin B12 deficiency. 
    • Issues with mental health: A lack of vitamin B12 can hurt mood and increase the risk of mental health issues.
  • Vomiting and diarrhoea: Vitamin B12 deficiency may impact the digestive system. Insufficient red blood cells indicate insufficient oxygen delivery to the stomach. A person may feel unwell due to lack of oxygen which can further lead to diarrhoea.
  • Loss of appetite and weight: Those who are deficient in vitamin B12 may experience nausea and other digestive issues that make them lose their appetite. Over time, a decreased appetite may result in weight reduction.

Treatment for Vitamin B12 Deficiency

The course of treatment may change based on the severity and underlying cause of the deficiency. Some of the popular treatment options are:

  • Dietary modifications: Meat, fish, poultry, eggs, and dairy products are examples of animal products that are good dietary sources of vitamin B12.
  • Vitamin B12 injections: These are commonly used in situations of severe shortage or problems with malabsorption. They work well because they directly help in raising blood levels.
  • Nasal sprays: Nasal sprays are a wonderful option for those with malabsorption problems since they are a direct absorption type of supplement that enters the circulation.
  • Oral supplements: These might be useful for those with lesser shortages or issues with absorption of vitamin B12.


When the body does not have enough vitamin B12 to operate correctly, the body starts showing B12 deficiency symptoms. It may result in several symptoms, such as anaemia, tiredness, weakness, and neurological issues.

Inadequate dietary intake, intrinsic factor insufficiency, gastrointestinal diseases, and medicines are some of the reasons for B12 deficiency.

Contacting a doctor is crucial if the body starts displaying B12 deficiency symptoms.

Frequently Asked Questions

1. What symptoms indicate a low vitamin B12 level?

The majority of the time, weariness, lethargy, tingling feeling in the hands and feet, oral issues, disorientation, and irritability are the most typical vitamin B12 deficiency symptoms.

2. Why do people get B12 deficient?

A person may experience a vitamin B12 deficiency if their food is inadequate in the vitamin or if their body is unable to absorb it properly during digestion.

3. Is it possible for a vitamin B12 deficit to be fatal?

If left untreated, a deficit in vitamin B12 can cause significant harm to the brain system, increasing the chance of death. Pernicious anaemia—a shortage in red blood cell synthesis brought on by a deficit in vitamin B12 can result in irreversible brain damage and even death.

Disclaimer: We recommend consulting a Doctor before taking any action based on the above shared information.


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