Vitamin B12 deficiency

Vitamin B12 deficiency is one of the most common vitamin or minerals deficiency affecting vast majority of population. It can occur at any age but is more common in elderly above the age of 50. Signs and symptoms of vitamin B12 deficiency are;

  • Numbness
  • Tingling or pins and needles sensation in hands and feet
  • Shortness of breath
  • Paleness
  • Nervousness
  • Severe joint pain.

In extreme cases the vitamin B12 deficiency could lead to

  • Memory loss
  • Depression
  • Paranoia and delusions
  • Loss of smell and taste

In order to understand the causes and treatment of Vitamin B 12 deficiency clearly , it is essential to understand the role of vitamins b12 in human body , how much it is required and food sources.

Functions of vitamin B12

Vitamin B12 also called cobalamin is one of the water soluble vitamins . It is especially important for the maintenance of healthy nerve cells . It helps in the synthesis of DNA, RNA, and red blood cells. Vitamin B12 along with folic acid produce a compound called S-adenosylmethionine which plays an important part in immune system and helps to regulate brain chemicals effecting mood such serotonin, dopamine and melatonin. Vitamin B12 also works with other B vitamin to control blood levels of amino acids and homocysteine.

Recommended dietary allowance

The recommended intake of vitamin b12 are provided in dietary reference intake (DRI) for adults and average intake for infants. The RDA of vitamin B12 is expressed in microgram.


0-6 months 0.4 mcg

7-12 months. 0.5 mcg


1-3 years 0.9 mcg

4-8 years. 1.2 mcg

Males and females

9-13 years 1.8 mcg

<14 years. 2.4 mcg

Pregnancy. 2.6 mcg

Lactation. 2.8 mcg

Food sources

Human body is unable to produce vitamin B12 so it must be supplied through diet in sufficient amount in order to avoid deficiency. Vitamin B12 is found in the tissues of animals and is therefore present in food from animal sources including liver, kidneys, Muscle meat, poultry, fish, milk and milk products and eggs. It is not present in fruits and vegetables so people on vegetarian or vegan diets are more susceptible to vitamin b12 deficiency. There are many commercially available breakfast cereals that are fortified with B12 in order to ensure bioavailability of this vitamin to particular group.

Causes of vitamin B12 deficiency

Vitamin B12 deficiency is more prevalent in older people . The major cause of B12 deficiency in older adults is due the lack of inteensic factor, a protein which ia required for the absorption of vitamin B12 from food . This type vitamin B12 deficency is called pernicious anaemia and is more common in;

  • Adults over 60
  • Women
  • And people with postive family history of autoimmune disorders.

Common causes of vitamin b12 deficiency include

  • A strict vegan diet
  • Gastric ulcers
  • Thining of stomach lining
  • Intestinal surgery
  • Medications
  • Digestive disorders

The infants born to vegetarian pregnant mothers are more succeptible to vitamin B12 deficiency.


The treatement of vitamin B12 deficiency include nutritional intervention along with proper supplementation. A person on strict vegetarian diet or vegan diet are recommended to use B12 supplements daily between meals. Also commercially available vitamin b12 fortified cereals ,soya and yeast products can be used instead of the normal ones to ensure sufficient intake of vitamin B12.

For individuals not on any diet restrictions it is essential to include liver, milk, eggs and fish in diet frequently because it carries a good supply of vitamin B12 and other important nutrients.

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