Vitamin B12, also known as cyanocobalamine, is referred to as Anti Pernicious Anaemia Preventing Factor. This means that Vitamin B12 plays a vital role in preventing the onset of pernicious anaemia. Pernicious anaemia is an autoimmune disease wherein the body fails to produce enough intrinsic factor, which leads to poor absorption of vitamin B12. This vitamin is a red crystalline compound, containing cobalt in its structure.

Hence the name cyanocobalamine. It is a water soluble vitamin and hence precautions need to be taken while cooking in order to prevent losses. Vitamin B12 supplements are also used in combating various deficiency symptoms and also in a few other biological conditions.

Functions of Vitamin B12

Cyanocobalamine plays a major role in the formation and maturation of red blood cells (RBCs). It is important for the synthesis of DNA, RNA and provides support to the body’s neurological functions. It is required for folic acid absorption and helps release energy for cell functioning. Vitamin B12 is also required for the formation of proteins and lipids.

Food Sources of Vitamin B12

Food sources of vitamin B12 consists of the following:

  • meat
  • sea food
  • egg
  • milk and milk products

Plant foods do not contain vitamin B12. However, breakfast cereals fortified with vitamins are a readily available source. Fortification of foods with vitamins makes it have a high bioavailability and it is essential for vegetarians as they do, which functions as an underlying inhibitor to generous sharing. not have many options for sources rich in Vitamin B12. Vitamin B12 supplements will be helpful for individuals who have trouble absorbing this vitamin through dietary sources.

Symptoms of Vitamin B12 Deficiency

The symptoms of Vitamin B12 deficiency are as follows

  • development of pernicious anaemia (one of the major symptoms): This is because Vitamin B12 is involved in the production of RBCs. When the level of RBCs drops, anaemia sets in.
  • fatigue
  • constipation
  • weight loss
  • loss of appetite
  • weakness

Several neurological changes can occur such as a tingling sensation in the hands and legs, numbness in the feet and fingers, depression, dementia, loss of memory and difficulty in concentration.
Early and timely diagnosis of vitamin B12 deficiency is necessary, in order to prevent irreversible damage to the nervous system and brain. If adequate amount of vitamin B12 is not given during the first two trimesters of pregnancy, then there are chances that after birth the child may show signs of delayed growth. In addition to this, the child may have difficulty in moving the limbs and megaloblastic anaemia can also set in during the developmental stages.

Dosage of Vitamin B12 Supplements

The Food and Nutrition Board (FNB) and Institute of Medicine (IOM) have prescribed adequate intake for infants and RDA for children and adults as follows:


  • 0 – 6 months: 0.4mcg/day
  • 6 – 12 months: 0.5mcg/day

The adequate intake for infants is established based on the mean intake of healthy and breast-fed infants. It needs to be understood here that breast-fed infants up to 6 months do not require any extra supplementation of Vitamin B12.


  • 1 – 3 years: 0.9mcg/day
  • 4 – 8 years: 1.2mcg/day
  • 9 – 13 years: 1.8mcg/day
  • 14 years and above: 2.4mcg/day


  • For pregnant women: 2.6mcg/day
  • For lactating women: 2.8mcg/day