Author: Jacqueline Newson, BSc (Hons) Nutritional Therapy

Top Five Sources Of Vitamin B12

Top Five Sources Of Vitamin B12

If you are reading this you may have some concerns about whether you are getting enough vitamin B12 in your diet.

It could be you are venturing into veganism, are already a vegetarian or perhaps have an eating disorder that is affecting your nutrient status.

You could also just be curious about what the best food sources are, in any case, this article will help you to understand why vitamin B12 is important and which foods will give you the best supply for your specific needs.

Table of contents


What is Vitamin B12 and What Does it Do?

Vitamin B12 is an essential water-soluble vitamin that contains the mineral cobalt.

It has a wide range of functions in the body:

  • It stimulates growth and appetite in children
  • It is essential for nervous system function
  • It is linked with synthesis of neurotransmitters such as dopamine and serotonin
  • It activates the utilization of carbohydrates, fats and proteins for energy It aids in red blood cell formation
  • It is involved in the synthesis of DNA, the genetic blueprint of your body

Vitamin B12 is bound to protein in food. During digestion, hydrochloric acid in the stomach releases it from the protein.

Once released B12 combines with another chemical substance called intrinsic factor (IF) before it is absorbed into the blood circulation through the small intestines. (1)

This process requires adequate levels of stomach acid and the effective production of IF. Calcium and thyroid hormones also assist in the absorption of B12. (2)

With such a variety of roles in the body, it’s little wonder that vitamin B12 deficiencies may lead to health problems.

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What Causes Vitamin B12 Deficiency?

Even though vitamin B12 is water soluble, it can be drawn from sources such as sloughed intestinal cells and stored in the body for several years.

Consequently, a nutritional deficiency is extremely rare and it may take years for a deficiency to become apparent.

Where deficiencies are identified there may be a number of causes:

  • It can be due to poor absorption as a result of pernicious anaemia (a form of anaemia that occurs when there is an absence of IF).

  • It can arise due to conditions that interfere with B12 absorption, such as inflammatory bowel disease, H Pylori infection (4) or gastric surgery.

  • Certain drugs such as heartburn medication can reduce stomach acid production, which interferes with vitamin B12 absorption. 

  • During pregnancy when there are higher demands for vitamin B12.

  • The elderly are at a higher risk of a deficiency because they frequently produce too little stomach acid. This means the vitamin B12 cannot be liberated from food by stomach acid and then bound to IF, to facilitate its absorption.

  • The parietal cells that release IF can be damaged in individuals with inflammation of the stomach or gastritis, which leads to impaired IF production and decreased stomach acid, resulting in B12 deficiency. No amount of vitamin B12 rich foods will help because the sufferers are unable to absorb it adequately.

  • Dietary sources of vitamin B12 are primarily found in foods of animal origin, although edible algae such as dried purple laver (also called Nori) have been found to contain a substantial amount. (6)

Strict vegans and vegetarians are therefore at greater risk of B12 deficiency. What’s more, because body stores may remain normal for three to six years, deficiency of vitamin B12 is usually not apparent until after many years of vegetarianism. (3)

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Symptoms of Vitamin B12 Deficiency

Vitamin B12 works similarly to folic acid, therefore high folic acid levels can mask a B12 deficiency for a period of time.

Severe deficiency is characterised by a number of symptoms including the following:

  • Nervous symptom disorders, such as mood changes with mental slowness
  • Pernicious anemia (enlarged and fewer red blood cells)
  • Fatigue
  • Palpitations
  • Shortness of breath
  • Feeling dizzy
  • Chest pains
  • Headache
  • Weakness
  • Menstrual problems
  • Depression
  • Sleep disturbances
  • Memory loss
  • Numbing, burning or tingling of the hands and feet.

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The Consequences of B12 Deficiency

Studies have shown that a deficiency of vitamin B12 can lead to abnormal neurologic and psychiatric symptoms, such as spasticity, incontinence, muscle weakness, vision problems, psychoses and mood disturbances. (5)

A deficiency is also an important factor in dementia.

Researchers report that these symptoms may occur when vitamin B12 levels are just slightly lower than normal and are considerably higher than the levels normally associated with anaemia.

Administering vitamin B12 orally, intramuscularly, or intranasally is effective for preventing and treating dietary vitamin B12 deficiency.

Those who lack the ability to produce IF require vitamin B12 shots to bypass the digestive system.

There are some supplements available that are administered sublingually, which have also been found to bypass the stomach and are therefore an effective therapy for deficiencies.

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Top 5 Food Sources of Vitamin B12 


1. Offal

Liver, kidney. 75g lambs liver provides 52-66mcg

2. Seafood

Shellfish or fish. 75g of mussels supplies 18mcg.

3. Red meat

Beef, pork, lamb. 85g beef steak supplies 6.9mcg.

4. Poultry

Turkey, chicken, duck, goose, partridge, pheasant. 85g turkey provides 0.8mcg.

5. Dairy

Milk, cheese, yogurt. 50g of Emmental (Swiss cheese) supplies 1.7mcg.


* Vegans and vegetarians should supplement with synthetic vitamin B12, which is also added to some fortified foods such as breakfast cereals.

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Recommended Doses

Infants 0-6 months 0.4mcg/day
Infants 7-12 months 0.5mcg/day
Children 1-3 years old 0.9mcg/day
Children 4-8 years old 1.2mcg/day
Children 9-13 years old 1.8mcg
Adolescents 14 and older 2.6mcg/day
Men and women 18 and older 2.4mcg/day
Pregnant women 19 and older 2.6mcg/day
Breastfeeding women 19 and over 2.8mcg/day

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Although vitamin B12 deficiencies are rare, if you are displaying typical symptoms it is important to visit your GP.

A satisfactory outcome may put your mind at rest, but if you are still concerned about your health a stay at an Amchara personalised health retreat can be an important stepping-stone towards optimum health.


Free Personalised Health Consultation with Amchara




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