Vitamin B12 is also popularly known as cobalamin, as it contains a metal ion (cobalt). Only archaea & bacteria are able to produce this water soluble vitamin.Vitamin B-12 can be categorized as one of the most complicated and largest vitamin that man has ever encountered till date.

Vitamin B12 happens to be a collection of compounds that are related chemically and have activities commonly attributed to the Vitamin class. We can find cobalt in it which is probably the rarest of the elements that can be found biochemically. Only a bacterium has got the capacity to perform the biosynthesis of the basic architecture of this vitamin. Only the human body has the capability of performing conversions between the different forms of the vitamin. This most commonly available synthetic form of this vitamin is called cyanocobalamin. It is not obtained in a normal form in nature.

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It has to be produced chemically from bacterial hydroxyocobalamin. Because of the stable nature and low production cost this is used by many pharmaceutical companies in medicines, supplements and food additives. Once inside the body it is converted to methylcobalamin and adenosylcobalamin.However it leaves behind cyanide in very insignificant quantities. Recent studies have shown the presence of hydroxocobalamin, methylcobalamin, and adenosylcobalamin inexpensive medicine and supplements.However the effectiveness of this extra amount is currently the topic of a hot debate.

Major role to play

Usually it plays some major roles for nervous system, brain, formation of blood. The vitamin plays an important role in the metabolism process of each cell in the human body. This has significant impacts on the synthesis and regulation of DNA, the synthesis of fatty acid and production of energy.

Forming red blood cells

The most important function of Vitamin B12 is aiding the development of red blood cells. The red blood cells need the information from DNA molecules when they mature (DNA is the nerve center of our cells in which our genetic information is encoded). In case of deficiency of Vitamin B12, the DNA synthesis becomes improper and this in turn impacts the information meant for the Red Blood Cell formation. This leads to a condition called pernicious anemia characterized by oversized cells having a bad shape and functioning improperly. In most of the cases it has been found that the real cause of pernicious anemia is a lack of proteins made in the stomach that are required for Vitamin B12 absorption.

Developing nerve cells

Another important function of Vitamin B12 is aiding the development of nerve cells. Myelin sheath is a coating that enclosed the nerves. This coating does not get formed in sufficient quantities if the person is Vitamin B12 deficient. It also plays an indirect role in lessening or relieving pain and other commonly known symptoms of disorders in the nervous system..

Other roles for vitamin B12

Protein is a very vital ingredient for promoting growth and cell repairs. However Vitamin B12 is essential for proper circulation of protein in the human body. Amino acids and other important components of protein become really unusable when B12 is not present in adequate amounts. Since Vitamin B12 is also required for processing carbohydrates and fat specially for completing one of the steps, problems in proper movement of carbohydrates and fat happen when Vitamin B12 is present in insufficient amounts.

Symptoms of vitamin B12 deficiency

Vitamin deficiencies can take various years to show its effects on people. Initial indications could be unnoticeable, however as time goes it turn noticeable.

Some indications are weakness, weight loss, and loss of appetite, fatigue, skin swelling or rashes, headache, anemia etc. Enough quantity of vitamin B12 is required to multiply our cells properly. In every minute our body is producing millions of blood cells. When you are suffering from vitamin B12 deficiency then the manufacturing decreases & it causes anemia. Because of anemia you could suffer from palpitation as well as shortness of breath & fatigue too.

Anemia can affect you in various other ways too. Like, diarrhea, high chances of infection, pale skin, menstrual problems, sour mouth etc.

When this deficiency continues for a long period of time without any treatment, then you can experience tender calves, irritability, numbness of the fingers, confusion, muscle weakness, forgetfulness, staggering tingling of toes etc.

Some risk groups are

Older Adult with Atrophic Gastritis

Because of such condition hydrochloric acid secretion in stomach minimizes, which causes minimum absorption of vitamin B12.

People with pernicious anemia

Individuals suffering from pernicious anemia are not capable of devouring vitamin B12 at the gastrointestinal track. However prescribed high doses of vitamin B12 have been found to be quite useful for treating such conditions.

Lactating or pregnant women with Veg diet

Women who breastfeed their babies heavily & follow a strict vegetarian diet can experience such deficiencies.

Among infants

Indications like movement disorders, megaloblastic anemia, delayed development, failure to thrive can also be found among infants. Untreated for long periods of time can lead to neurological injuries too.

Some negative impacts of Vitamin B12

  •  Sometimes Treatment of deficiency of vitamin B12 can unearth polycythemia vera. This can be identified by blood volume increase which in turn results in an increase in the number of red blood cells. Treatment of megaloblastic anemia using vitamin B12 can lead to a fatal state of hypokalemia and gout. You need to be cautious.
  •  In addition to the above sometime Leber’s disease can also appear.

Some Natural sources of Vitamin B12

Eggs: if you are talking about chicken eggs then the raw yellow portion has the maximum amount of vitamin B12, like per 100 g serving it has 1.95μg. This equals to about 0.33μg per yolk or just 6% of the DV.

Cheese: The amount of the vitamin depends on the different types of the cheese. Nonetheless Swiss cheese is known as a major provider with 3.34μg per 100g serving, followed by Gjetost, Mozzarella, Parmesan, Tilsit & Feta.

Milk & Yoghurt: Milk & yoghurt are also quite popular as sources of vitamin B12. While low fat milk provides 19% DV per cup & 0.46μg (8% DV), fat free yoghurt is able to provide 15% DV per cup & 0.53μg (10% DV) of vitamin B12.

Yeast extract spreads: This excellent source of protein as well as vitamin B12 is quite famous in Europe, especially in Britain & has been able to take its charisma to U.S.A. Too. A hundred grams of this gives 0.5μg (8% DV) of vitamin B12, which is around 0.03μg (1% DV) per teaspoon.

Whey Powder: It has gained quite a bit of popularity, especially among vegetarian people. 100 grams is able to provide afford 2.5 μg of vitamin B12.

Some non-vegetarian sources are


Shellfish like mussels, oysters & calms are huge suppliers of vitamin B12. In addition to that it also provides iron along with copper & zinc. You can have it directly or steamed, fried, baked, etc.


Most of the animal livers are good sources of vitamin B12. Animals like beef, moose, veal, lamb, goose, duck & turkey occupies the initial spots.

Fish Eggs/ Caviar

Caviar is considered as a very expensive food. You can have it as a spread or even as a garnish. However egg of whitefish provides the maximum vitamin B12.


It is quite popular in Japanese, Mediterranean & Hawaiian dishes. The octopus is also a very rich & well known supplier of vitamin B12.


This high protein as well as omega 3 suppliers is also popular for their vitamin B12 source. Mackerel occupies the top spot as a maximum vitamin B12 provider.

Crab and Lobster

Usually they are served as steamed or baked or even in a curry. These tasty ingredients are also a great supplier of vitamin B12.


Along with zinc, heme-iron & protein beef is an excellent provider of vitamin B12. Though the quantity of the vitamin relies on the cut, but lean fat trimmed portions have been considered to be maximum suppliers of vitamin B12.


Lamb is quite common food in Europe along with East Asia, Mediterranean, New Zealand, Middle East & Australia. Since it has high cholesterol content, make sure you are having a lean portion. Protein & zinc have also been found in lamb meat. The shoulder portion is considered to have the maximum amount of vitamin B12.

Vitamin B12 is also able to avert various health conditions like asthma along with leukemia, multiple sclerosis, alcoholism, arthritis, celiac disease, Epstein Barr virus, anemia, lupus, neuropathies etc.

Public Health Recommendations for Vitamin B12 by WHO

The most recent Recommended Dietary Allowances (RDAs) for vitamin B12 was provided by the National Academy of Sciences. The RDAs was recorded for all persons more than 1 year old. For infants younger than 1 year, Adequate
Intake (AI) levels were established. The guideline for AI and RDA are listed below:

  •  0-6 months: 400 nanograms
  • 6-12 months: 500 nanograms
  • 1-3 years: 900 nanograms
  •  4-8 years: 1.2 micrograms
  •  males 9-13 years: 1.8 micrograms
  • males 14 years and older: 2.4 micrograms
  •  females 9-13 years: 1.8 micrograms
  •  females 14 years and older: 2.4 micrograms
  •  Pregnant females of any age: 2.6 micrograms
  •  Lactating females of any age: 2.8 micrograms

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