Are you at risk of Vitamin B12 Deficiency?

B12 deficiency Mar 15, 2019


Recently I heard many people complaining that they have been detected with Vitamin B12 deficiency. What is the importance of this vitamin and what will happen if its deficiency prevails? In this article we will cover all these issues related to Vitamin B12 deficiency.

Vitamin B12 also known as Cobalamin, is responsible for many important functions in the body. It is water-soluble vitamin and therefore its loss during cooking is very high. Vitamin B12 has basic role in production of Red blood cells, DNA synthesis, metabolism of amino acids and fatty acids. Also it helps in proper functioning of nervous system.

It is naturally found in all non-vegetarian animal based foods like meat, fish, eggs, poultry and dairy products. Unfortunately, vegetarian sources are deficient in this vitamin. However, certain foods like breakfast cereals, bars, and soya milk are fortified with this vitamin and therefore Vitamin B12 deficiency is very common amongst vegans. Some of the more specific sources include pork, beef, ham, lamb, and fish like tuna, haddock, and milk products like cheese, yoghurt and finally eggs.

Vitamin B12 can be stored in body up to four years but excess of it is excreted via urine. Recommended dietary allowances (RDA) of Vitamin B12 is 2.4 mcg for adults but its need increases to 2.6-2.8mcg during pregnancy and lactation phase.

Apart from production of RBC’s, Vitamin B12 enables the production of energy by absorbing folic acid. Therefore any defect in this mechanism can lead to deficiency symptoms of B12. Similarly, RBC’s cannot multiply without this crucial vitamin and therefore reduction in B12 can cause anaemia which is specifically called pernicious anaemia.

Deficiency Symptoms of B12

When body cannot absorb vitamin B12 or dietary sources lack B12 or due to any defects in stomach intrinsic factor Vitamin B12 deficiency occurs. Normal blood serums levels of Vitamin B12 are between 200-800ng/l. General Symptoms include:

·        Anaemic symptoms like: weakness, fatigue, shortness of breath, tiredness.

·        Neurological changes like: numbness, tingling of hands and feet, difficulty in balancing, memory loss, depression, confusion, feeling sad for no reason and dementia.

·        Gastrological symptoms like: loss of appetite, constipation and weight loss.

·        Infertility

·        Hypothyroidism.

Neurological symptoms can occur even without anaemia. They can be considered early signs and if person shows such symptoms of neurological disturbances he/she should be checked for anaemia symptoms and then blood levels for B12. Many people confuse these neurological symptoms with that of age related changes but surprisingly elderly are maximum at risk of this deficiency.

Infants who lack vitamin B-12 show unusual movements, such as face tremors, as well as reflex problems, feeding difficulties, irritation, and eventual growth problems if the deficiency is left untreated.

Megaloblastic anaemia

Megaloblastic anaemia is a condition when there is abnormally large size of Red blood cells but less in number or less than normal values. This happens because of absence of protein ‘intrinsic factor’ in stomach which is responsible for the absorption of Vitamin B12. Megaloblastic anaemia caused due to deficiency of Vitamin B12 is also called pernicious anaemia.

Due to its large size in this condition, RBC’s are not able to exit from the bone marrow where they are produced into the blood stream and therefore its function of carrying oxygen to various cells is hampered causing symptoms of anaemia.

Looking at the normal range of blood serum of Vitamin B12 content, any value towards its lower sides but within range has to be treated as soon as possible through dietary modifications and making sure Vitamin is absorbed well into blood streams. Malabsorption is main cause of this value to be on lower side which can be corrected.

Who at risk?

Various groups of people are at risk of Vitamin B12 deficiency due to physical and inappropriate dietary reasons. Let’s look at them:

1.Elderly population: In elderly population over the age of 50 years B12 deficiency is not due to inadequate dietary supply of B12 but more due to various pathophysiological and physiological changes that occur due to increasing age. Bioavailability of vitamin is affected due to less or decreased absorption capacity of intestines, absence of intrinsic factor or as a side-effect of medications in old age. Other factors like gastrointestinal pH, H.pylori infection and Malabsorption syndromes are contributing factors for Vitamin B12 deficiency.

2.Vegetarians: Since B12 is found mainly in non-vegetarian sources like meat, eggs, fish, vegetarian population who doesn’t consume these products are at major risk of developing this deficiency. However certain foods like breakfast cereals and milk is now fortified with B12 but not many people consume these products on daily basis in India.

3. People with Crohn’s disease, celiac disease and pernicious anaemia: Crohn’s disease and celiac disease reduces the capacity of intestines to absorb Vitamin B12 resulting into deficiency.

4.Taking various high dosage heavy medications: Various medicine like colchicine, metformin (diabetes drugs), antibiotics like neomycin, and gentamycin for prolonged period, acidity medicine like beta blockers reduce the absorption of B12.

5. Surgeries: People who have undergone surgery like gastric bypass or any other stomach surgery might compromise with the absorption capacity of B12.

6. Alcoholism and smoking: Alcohol and smoking also reduces the capability to absorb B12.

7. Multiple factors: Elderly people with diabetes on metformin drugs since long time and vegetarian are at highest risk of developing B12 deficiency.


Vitamin B12 deficiency is treated by administrating dosage of vitamin either orally or injecting intramuscularly. Injecting the dose is more into practice because it bypassed the issue of malabsorption and is released directly into muscles at their site of action.

However higher dosage of 2,000 mcg of oral vitamin B12 daily, followed by a decreased daily dose of 1,000 mcg and then 1,000 mcg weekly and finally, monthly might be as effective as intramuscular administration.

All above this individual capacity to absorb varies on many factors. However intramuscular injections are most effective, preferred and fast means to control deficiency of Vitamin B12.


B12 deficiency can be prevented by:

1.     Non-vegetarians should include its dietary sources like meat, fish poultry regularly to meet the requirement of 2.4mcg daily.

2.     Vegetarians who do not consume non-veg should take supplements after they cross 50 years of age. They can also include fortified cereals, soy milk fortified with B12, and other products to prevent the deficiency.

3.     Regular exercise should be done to ensure healthy lifestyle and proper absorption of nutrients.

4.     Reduce the intake of alcohol and smoking.

Prevention is always better than cure! so stay healthy stay fit!




Shruti karnik

Holding a masters degree in Foods and Nutrition from Foods and Nutrition dept of MSU, Vadodara with 5 yrs experience in various hospitals. specialty in cardiac health, weight issues, diabetes, hypert

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