The ten important clinical signs of Vitamin B12 deficiency

Cyanocobalamine, often known as vitamin B12, is a water-soluble vitamin. The only vitamin with no recognised sources in plants is this one.  Thus, vitamin B12 insufficiency is particularly dangerous for vegans. DNA synthesis in cells is carried out by vitamin B12. Deficient individuals develop symptoms because of the reduced formation of rapidly proliferating cells.

Important symptoms of Vitamin B12 deficiency

  1. Pallor or anemia:

    • Vitamin B 12 deficient individuals develop macrocytic anemia.
    • Apart from low hemoglobin, these individuals may also have low platelet count and low White blood cells.
  2. Lethargy, weakness, and tiredness:

    • These non-specific symptoms may be related to anemia but occasionally may be present in patients without anemia.
  3. Palpitation and shortness of breath

  4. Smooth tongue (loss of papillae) and  oral ulcers:

    • These changes may be seen in other vitamins deficiency as well like thiamine and riboflavin
  5. Tingling and numbness of the hands and feet:

    • These are among the common symptoms.
    • Patients may have these neurological symptoms without even having anemia
  6. Limb weakness and difficulty in walking:

    • Loss of joint position sense may lead to a waddling gait, frequent falls, and difficulty in walking
  7. Impaired vision:

    • Vitamin B 12 deficiency causes optic atrophy impairing vision
  8. Reduced memory, depression and behavioral changes:

    • Dementia or loss of memory, mental and psychological problems may be seen in vitamin B 12 deficiency as it is responsible for the synthesis of the myelin sheath, a covering around the nerves.
  9. Early graying of hair and looking old:

    • This is a common symptom and is occasionally associated with vitamin B 12 deficiency.
    • Patients look aged and older than their actual age.
  10. Jaundice:

    • People who lack vitamin B12 have blood cells that are excessively big and are eliminated by the spleen.
    • Bilirubin is produced when haemoglobin is converted, which causes splenomegaly and jaundice.

Are You at Risk of developing vitamin B 12 deficiency?

A number of disorders can exhibit vitamin B12 deficiency. The following demographics are most susceptible to acquiring vitamin B12 deficiency:


  1. An inadequate diet like vegetarians, malnourished and patients on protein restriction due to kidney or renal diseases leads to a deficiency of vitamin B12.
  2. Patients with intrinsic factor deficiency also known as pernicious anemia,
  3. Those who have had gastrectomy,
  4. Patients who suffer ileocecal illnesses like Crohn's disease or tuberculosis are also susceptible to acquiring a vitamin B12 deficit.
  5. People with diabetes receiving long-term metformin therapy.

Daily requirements:

RDA for men and women is 2.4 ug/day. RDA for pregnant females is 2.6 ug/day and for lactating women, it is 2.8 ug/day. The following are the daily recommended required amounts of vitamin B 12 according to a person's age:

  1. Infants up to age 6 months: 0.4 mcg
  2. Babies age 7-12 months: 0.5 mcg
  3. Children age 1-3 years: 0.9 mcg
  4. Kids age 4-8 years: 1.2 mcg
  5. Children age 9-13 years: 1.8 mcg
  6. Teens age 14-18: 2.4 mcg (2.6 mcg per day if pregnant and 2.8 mcg per day if breastfeeding)
  7. Adults: 2.4 mcg (2.6 mcg per day if pregnant and 2.8 mcg per day if breastfeeding).

What are the Sources of vitamin B12?

Milk, eggs, meat, and liver are good sources of vitamin b 12. Bacteria in the human gut can also synthesize vitamin b12 but since they reside in the colon where absorption does not take place, vitamin b12 produced by the bacteria can not be used by the human body. 

The absorption of dietary vitamin B12 may be decreased by drugs like long term usage of antacids, proton pump inhibitors, and diabetic  medications like metformin.

How to treat Vitamin B 12 deficiency?

Treatment of vitamin B 12 deficiency should focus on identifying the underlying disease first. Diseases causing vitamin B 12 deficiency have been mentioned above. Treatment is best given as parenteral therapy. Oral vitamin B12 is less effective in patients who have neurological features, severe deficiency and those with problems in the gastrointestinal tract. If oral formulations are given, it is best to give it with an intrinsic factor to increase the absorption. Some pharmaceutical companies have launched the sublingual forms of vitamin B12 which are readily absorbed and does not need intrinsic factor for absorption. The parenteral form of vitamin B 12 should be given for ten consecutive days, then weekly for four to six weeks and then monthly.

Vitamin B 12 in Pakistan:

Some of the popular brands of vitamin B 12 in Pakistan include:

  1. Neuromet
  2. Neurobion
  3. Neurobedoxine
  4. Methycobal
  5. Mecobal


M Waqas

Sir if u add the exact parenteral replacement dose and method of vitmain b12 and its co adminstration with folic acid uses , it will be more additional to knowledge .

Yahya khan

Sir we appreciate your effort by making our knowledge and concept clear. Thank yu so much sir.