Vitamin B12

Vitamin B12 absorption

Hydrochloric acid in the stomach releases B12 from protein during digestion and once released, B12 combines with a substance called intrinsic factor (IF) before it is absorbed into the bloodstream.  When you digest any forms of protein does it cause indigestion, bloating or reflux?  If so then you may have insufficient digestive enzymes and acids to properly absorb Vitamin B12 as it needs a acidic digestive environment to be absorbed.  Apple cider vinegar or digestive enzymes may help to absorb more Vitamin B12 by increasing hydrochloric acid and pepsin production into the stomach.

Vitamin B12 is absorbed through the small intestines and therefore a healthy environment needs to be ensured in order for this to occur.  I suggest taking a probiotic supplement such as Ethical Nutrients Inner Health Plus (one first thing in the morning and one last thing at night).  This will help to provide the proper bacteria in the gut and bowels and may help to increase the absorption of this vitamin.

Raising Vitamin B12 levels will take time and it is especially beneficial to continue taking a tablet while also having B12 injections from your GP.  However, once these injections cease it is still recommended to continue taking a multivitamin supplement to ensure that your Vitamin B12 status is sustained.  It is also a good idea to take also a separate B Vitamin formulation after the course of injections.  A supplement of around 1000mcg/ day for a few months will ensure that your levels of this vitamin are kept high.


Vitamin B-12 is involved in the metabolism of every cell of the body, especially affecting the DNA synthesis in cells but also fatty acid synthesis and energy production.  It helps maintain healthy nerve cells and red blood cells and is also needed to make DNA, the genetic material in all cells.

Injections of Vitamin B12 or supplements may help the following conditions:

  • blood abnormality (pernicious anaemia)
  • low red blood cell count (megoblastic anaemia or pernicious anaemia)
  • B Vitamin deficiency Alzheimer’s disease
  • fatigue and Chronic fatigue syndrome
  • heart disease
  • high cholesterol
  • Coeliac’s Disease, Cronhs Disease, Irritable Bowel Syndrome or inflammatory bowel conditions where Vitamin B12 absorption through the small intestines is decreased due digestive inflammation and damage.
  • sleep disorders (circadian rhythm)
  • ataxia (shaky movements and an unsteady gait)
  • muscle weakness
  • dementia, psychoses, depression and mood disturbances
  • skin conditions such as vitiligo and dermatitis


Interestingly, the human body (liver) actually stores several years’ worth of vitamin B12 (between 3000 – 5000mcg), so nutritional deficiency of this vitamin is usually rare. The average healthy human adult has a total of 3,000 – 5,000 micrograms of Vitamin B12 stored in their Liver.

A deficiency in this vitamin occurs due to:

  • individuals who are unable to utilise vitamin B12
  • an absorption problem where Vitamin B12 is not able to absorb from the intestinal tract (pernicious anaemia)
  • strict vegetarians or vegans
  • elderly people are prone to deficiencies due to impaired digestive absorption
  • pregnancy, due to increased demand for the vitamin
  • thyroid conditions (toxicity of the thyroid)
  • anaemia, blood loss (hemorrhage) or heavy bleeding in females
  • malignancy
  • liver or kidney disease


Vitamin B12 is an essential vitamin which is commonly found in foods such as fish, shellfish, meats and dairy products.  It is mostly found in animal products due to it binding to the protein component of the food.

Vitamin B12 is not bio available in vegetables and is present only in minimal amounts in fermented products.  It is produced in the body by bacterial synthesis in the bowels but is excreted in high amounts in the faeces, it is therefore recommended to continual ensure that your diet contains regular intakes of this essential vitamin.  Long term vegetarians and vegans are can become prone to Vitamin B12 deficiencies, this is because a true vegan or vegetarian diet contains almost no Vitamin B12.

Vitamin B12 mcg/ 100g of food:

  • Nori Seaweed 55
  • Kombu Seaweed 27
  • Trout 5
  • Tuna 3
  • Sardines 17
  • Salmon 4
  • Mackerel 10
  • Tempeh 5
  • Lamb liver 104
  • Kidneys 30
  • Beef Liver 80
  • Chicken Liver 25
  • Eggs 2
  • Milk 3
  • Spirulina and breakfast cereals fortified with Vitamin B12 contain trace amounts

Why do I feel sick when I take my Vitamin B12 tablet?

It is quite common that people experience nausea while taking any form of Vitamin B supplements, including Vitamin B12.  This is because B Vitamins help to stimulate digestive secretions which can cause digestive acids to be released into the stomach resulting in symptoms of nausea.  It is always recommended to take B Vitamins with food rather than on an empty stomach to reduce this problem.