Vitamin B12 Deficiency: Causes And Symptoms



Published on: 07-Sep-2022


10 min read


Updated on : 02-Nov-2023




Amrita Sandhu


Vitamin B12 Deficiency: Causes And Symptoms

Vitamin B12 Deficiency: Causes And  Symptoms

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Did you know that vitamin B12 cannot be produced by the body but is very important?

B12, a water-soluble vitamin, is also known as cobalamin and is found mainly in animal products like chicken, eggs, meat etc. The function of vitamin B12 in the body is vital as it ensures the functioning and formation of RBCs, DNA synthesis and nerve cells.

The deficiency of vitamin B12 is prevalent among Indians because a vast majority are vegetarians. Vegetarian and vegan food does not provide enough B12, which causes deficiency. On the other hand, high amounts of vitamin B12 are present in non-vegetarian food. Apart from certain foods being a source of this vitaminB12, supplements like tablets and injections are also available in the market. Some foods are fortified with Vitamin B12 and are readily available in the market.

Table Of Contents

1. Prevalence of B12 deficiency in Indians

2. Causes Of Vitamin B12 deficiency

3. Signs And Symptoms Of Vitamin B12 deficiency

4. Sources Of Vitamin B12

5. The Final Say


Prevalence Of B12 Deficiency In Indians

From an urban endocrine practice, a database of 11913 patients was searched for reports of vitamin B12 levels. Prevalence of this deficiency with Vitamin B12 levels <200 pg/ml in tier 3 cities was 47.19%.

The prevalence of vitamin B12 deficiency was 37.76% in people with pre-diabates, 31.23% in people with endocrine problems other than diabetes, and 18.25% in people with diabetes. 

The prevalence of vitamin B12 deficiency is 47% in the north Indian population. 

Causes Of Vitamin B12 Deficiency

1. Anaemia (Pernicious)

Some people are born with pernicious anaemia. These anaemia cells are attacked by the immune system in the abdomen, negatively affecting the absorption of Vit B12. The symptom of pernicious anaemia includes:

  • Fast heartbeat
  • Tiredness
  • Weakness
  • Pale skin

2. Age

Our body needs hydrochloric acid to absorb B12. Some people suffer from atrophic gastritis because their stomach does not make enough of this acid and thus suffer from B12 deficiency.

However, B12 is readily absorbed from fortified foods and supplements in atrophic gastritis, so many doctors advise people older than 50 to consume B12-fortified foods.

3. Disorders Of The Intestines

B12 is absorbed in the intestines, but some disorders like Crohn's disease, ulcerative colitis, and IBS prevent B12 from absorbing into the intestines and hence cause deficiency. Some symptoms are:

  • Dementia
  • Confusion in the brain
  • Megaloblastic anaemia (more significant size of RBCs compared to normal RBCs and sufficiency of the same.

4. Certain Medications

Certain medications advised for diabetes, infections, heartburn, and seizures may hinder the absorption of Vitamin B12. For example, Metformin given to diabetic people to control the blood sugar level in the body may cause B12 deficiency.

Signs And Symptoms Of Vitamin B12 Deficiency

1. Fatigue 

B12 deficiency can lower the production of RBC hindering oxygen delivery.

2. Yellow And Pale Skin

Due to the low production of RBC in the body, skin turns pale yellow due to the deficiency of B12.

3. Depression 

In a 2020 study of 132 kids and teenagers, 89 had depression, and 43 did not. It was discovered that the individuals with depression exhibited lower B12 levels and greater homocysteine levels than those without depression.

4. Headaches

According to research, individuals with specific headaches seem more susceptible to low B12 levels. In addition, low levels of B12 can escalate the migraine issue, which elevates headaches as headaches are the most common symptom of B12 deficiency.

5. Hampered Concentration

Numerous studies have linked deteriorating mental health in elderly persons and low B12 levels. B12 deficiency hampers memory and cognition, lowering concentration power and making it difficult to concentrate on their daily chores.

6. Gastrointestinal Ailments

A deficiency of B12 can cause vomiting, nausea, gas, bloating, constipation, diarrhoea etc. In addition, the deficiency of B12 impacts the GI tract since there are fewer RBCs, which means a very low level of oxygen in the abdomen. This can cause nausea and diarrhoea. 

7. Inflammation Of The Tongue And Mouth

Ulcers and soars in the mouth or the tongue are caused due to Vitamin B12 deficiency.

8. Vision disturbance

B12 deficiency may damage the optic nerve and hinder the nervous signal which passes from the eyes to the brain, causing vision issues. 

9. Muscle Weakness And Muscle Cramps

B12 deficiency does not allow the body to produce enough myelin, an insulating layer that coats the muscle for protection, making the muscle weak and prone to cramps.  

10 Ataxia (Impaired Balance)

The person finds walking and balancing difficult due to a deficiency of B12. This is because it causes damage to the part of the brain which controls the coordination of muscles and all its connection.

11. Other

The deficiency of vitamin B12 has also caused Erectile dysfunction in some. Another common symptom to look out for is a needle sensation in the hands and feet.

Sources Of Vitamin B12

The following foods are some great sources of B12:

  • Poultry
  • Tuna and haddock fish
  • Yoghurt, milk, cheese and other dairy products
  • Eggs
  • Nutritional yeast products
  • Fortified milk products 
  • B12-fortified cereal products

The Final Say

The deficiency of B12 in India is widespread due to the preference for vegetarian food that hardly provides sufficient B12 to the body and causes deficiency which can raise various symptoms like pale or yellow skin, fatigue, mental impairment, headaches, pain, depression, and inflammation in the tongue and mouth. Therefore, make sure to notice all the signs and symptoms of the deficiency and consult your health care professional for the correct action.


1. What are the symptoms of B12 Deficiency?

Tingling effects in the feet and body, nausea, Anaemia, vomiting, bloating and some cognitive issues like difficulty in concentration and depression are the symptoms of B12 deficiency.

2. Does B12 deficiency cause hair fall?

Hair loss, lack of energy, ulcers and palpitations can occur when the blood B12 level falls below 300mg/l. 

3. Does B12 deficiency cause weight gain?

While there are many symptoms of B12 deficiency, no studies prove weight gain is one of them.

4. What medications cause B12 deficiency?

Medications for diabetes, heartburn, seizures and infections can hinder the absorption of B12 and cause B12 deficiency.

5. How quickly does B12 deficiency occur?

The human body can store B12 which can replenish the body for two to five years if healthy. After that, it takes a couple more years to develop the deficiency of B12.

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