Vitamin B12 is an essential micronutrient that helps keep your body healthy by supporting red blood cell production and DNA.

It is a water-soluble vitamin found naturally in foods such as meat, dairy products, eggs, fish and fortified cereals.

Vitamin B12 is needed for proper functioning of your nervous system, your DNA synthesis and the formation of your new cells. It also plays a role in maintaining your normal growth and development.

It is one of the eight important B vitamins. Vitamin B12 is also called cobalamin.

Sources of Vitamin B12

Vitamin B12 is found naturally in animal products such as:

  • Meat 
  • Milk 
  • Eggs
  • Fish 
  • And items that have been fortified with B12 (mostly suitable for vegetarians and vegans)

However, some people do not consume enough vitamin B12 through diet alone. Therefore, supplements are often recommended.

Required Intake of B12

Your required intake of vitamin B12 depends on your age, your eating habits, medical conditions and what medications you are on.

The recommended amounts of vitamin B12, measured in micrograms (mcg):

  • Babies upto 6 months: 0.4 mcg
  • Babies between 7and 12 months: 0.5 mcg
  • Children between 1 and 3 years: 0.9 mcg
  • Kids between 4 and 8 years: 1.2 mcg
  • Children between 9 and 13 years: 1.8 mcg
  • Teens between 14 and 18: 2.4 mcg (2.6 mcg per day if pregnant and 2.8 mcg per day if breastfeeding)
  • Adults 18 and above: 2.4 mcg (2.6 mcg per day if pregnant and 2.8 mcg per day if breastfeeding)

Vitamin B12 Deficiency

You may develop vitamin B12 deficiency in scenarios, such as:

  • Inadequate nutrient intakes
  • Malabsorption (a difficulty in the digestion or absorption of nutrients from food)
  • Prevailing medical conditions
  • Medications that deplete B12 levels that include some heartburn medicines.
  • Atrophic gastritis (a chronic condition that causes inflammation of the stomach lining)
  • Conditions that affect your small intestine, such as Crohn’s disease, celiac disease, bacterial growth or a parasite
  • Alcohol misuse or heavy drinking
  • Immune system disorders, such as Graves’ disease or lupus

If you are a vegan or a vegetarian (since you don’t eat animal products), you must take supplements to ensure adequate intake of B12.

Symptoms of B12 Deficiency

You can become anemic, if you have B12 deficiency. This happens when your body doesn’t have enough healthy red blood cells on account of your vitamin B12 deficiency.

These red cells transport oxygen throughout your body. You need vitamins to make them, including B12.

Normally mild B12 deficiency may cause no symptoms at all; however, if left untreated, it can leads to symptoms such as:

  • Fatigue and weakness
  • Paresthesia (nerve damage with numbness, tingling sensation in the hands and legs)
  • Memory loss and confusion
  • Dementia
  • Depression
  • Seizuresf
  • Heart palpitations and shortness of breath
  • Pale skin
  • A smooth tongue
  • Loss of appetite, constipation, diarrhea or gas
  • Megaloblastic anemia – a blood disorder that happens when your bone marrow produces stem cells that make abnormally large red blood cells. 
  • Pernicious anemia – caused by an inability to absorb vitamin B12


If you are diagnosed with vitamin B12 deficiency, there are a couple of treatment options readily available for you.

Vitamin B12 supplements are recommended for those who are at risk of vitamin B12 deficiency, such as old people, pregnant or nursing women, vegetarians and vegans.

It’s also recommended for those with intestinal problems and those who have had stomach surgery.

If you have pernicious anemia or have trouble absorbing vitamin B12, you may be requiring shots of B12 vitamins initially. You will also require high doses of B12 supplement by mouth or by nasal.

In case, you are a vegetarian, you can include in your diet vitamin B12-fortified grains, B12 supplements, B12 injections or even high-dose oral B12.

Vitamin B12 in supplements is synthetic (made by chemical synthesis), so vegans can take those supplements without worry. But do consult your doctor regarding use of synthetic nutrients as part of your dietary intake.

Nerve damage due to the B12 deficiency could be permanent, but here preventive healthcare can help you and lead you towards informed health decisions.

Preventive Healthcare and Nutrigenomics

Deficiency of vitamin B12 has been linked to your dietary, environmental and genetic factors.

People who have inherited conditions, which prevent their bodies from processing vitamin B12, may be prone to serious health issues, such as developmental delay (in children), psychosis, stroke and dementia.

Research data for the genetic basis of vitamin B12 is limited. But advancements in genomic techniques have increased the knowledge-base of the genetics of vitamin B12 status in humans.

In 2012, a team of international researchers discovered a new genetic disease relating to B12 deficiency. They identified a gene that is vital to the transport of vitamin into the cells of the body.

Advancements like this in gene research has helped doctors to better diagnose genes responsible for medical conditions and suggest newer and better treatment protocols.

And preventive healthcare, in the context of gene research, is not complete without nutrigenomics.

The goal of nutrigenomics is to prevent the onset and progression of chronic diseases through DNA-based dietary recommendations and lifestyle changes. This might come in handy for you and alter your life’s course towards better managing your B12 deficiency.


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Sources: National Institute of Health, Healthline, Harvard T.H. Chan School of Public Health, Medical News Today, Mayo Clinic, WebMd 1, 2 and McGill.

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