Vitamin B12 – Cobalamin

Vitamin B12 is chemically perceived as the largest and most complex vitamin. This water-soluble vitamin is microbiologically produced in the digestive tract of animals and is therefore contained exclusively in foods of animal origin. Vitamin B12 must bind to a special glycoprotein (Intrinsic Factor) so that it can be absorbed in the intestine.
The liver stores approximately 60% of the body’s vitamin B12, while the remaining amount (20–30 µg) is found in the kidneys, heart, spleen and brain. A large part of vitamin B12 passes through the gall bladder again to the intestines, where 65-75% of it is taken up and used again. Deficiencies usually only evolve over a period of serval years in people who eat small amounts of animal origin products or in people who are vegans.
A good vitamin B12 supply is important because it is involved in blood cell production, nerve sheath production and many other important functions.

Functions in the Body

  • Produces red blood cells
  • Produces genetic material (such as DNA)
  • Important for growth
  • Aids in energy production from nutrients
  • Maintains healthy nerve cells
  • Strengthens the immune system and heart’s health
  • Coverts the vitamin’s folate into the active form
  • Supports melatonin production and thereby controls the production of some hormones
  • Contributes to the control of the sleep-wake cycle

Deficiency Symptoms

  • Fatigue, nervousness, tingling sensation in fingers and toes, shortness of breath.
  • Severe vitamin B12 deficiency can cause nerve damage.
  • Groups at risk for vitamin B12 deficiency include vegetarians, vegans, elderly people and alcoholics. A lack of vitamin B12 inhibits Folate metabolism.


Overdose is not known.


+ None are known.
– Alcohol and a vitamin B6 deficiency reduce the absorption of vitamin B12. Various drugs and medications such as antibiotics, diabetes tablets, stomach tablets and contraceptives (“the pill”) reduce vitamin B12 absorption, as well.


Foodstuffs of animal origin such as meat, fish, seafood, offal, eggs and dairy products.

Recommended Daily Amounts

Young people 4 µg
Adults 4 µg
Adults over 65 years old 4 µg

«5 a Day» Helps Your Vitamin Supply

Vegetables and fruits do not contain any vitamin B12.