Monday, 26 july 2004

The Denby Report on Vitamin B12 deficiency
First Published Healthspan Feb 2010
Page 1 of 4
Vitamin B12 deficiency

The B vitamins are a group of 6 water-soluble vitamins that work together in the body
and are essential for growth and the proper development of a healthy nervous
system; for body maintenance, food digestion and general metabolism.
As they cannot be stored in the body it is important that adequate amounts are eaten
on a regular basis. Certain circumstances increase the need for B vitamins – for
example smoking, alcohol, il ness and stress deplete the body’s levels.
Vitamin B12
Also known as cyanocobalamin or cobalamin, vitamin B12 is released from food in
the stomach and has to bind with a substance called intrinsic factor, produced by the
stomach, in order that it is absorbed into the bloodstream. The amount of intrinsic
factor we produce declines with age, and hence our ability to absorb B12 is reduced.
Functions
Helps enzymes in the body to function – it is essential for the growth and division of
cells, as well as for making red blood cells, DNA and the sheath that surrounds nerve
fibres.
Food sources
Vitamin B12 is found naturally in food of animal origin but many foods, but some
breakfast cereals are fortified with it. The best food sources of vitamin B12 are:
 Seafood (white and oily fish and shellfish) There has been considerable research into plant sources of vitamin B12 – soya products, seaweeds and algae have all been proposed as potential source of B12. However the present consensus is that any B12 present in plant foods is likely to be unavailable to humans and so these foods should not be relied upon as safe sources. Many vegan foods are fortified with B12 but always check the label. Good sources of B12 for vegetarians are milk, cheese and eggs. Both vegetarians and vegans may benefit from taking a vitamin B12 supplement. The RNI for vitamin B12 in adults in the UK is 1.5 mcg per day with an addition 0.5mcg per day needed during breastfeeding. 40 Bowling Green Lane, London, EC1R 0NE
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The Denby Report on Vitamin B12 deficiency
First Published Healthspan Feb 2010
Page 2 of 4

Selected food portions and their contribution to vitamin B12 intake
Food and portion size
mcg vitamin B12


Who is at risk of deficiency
Vitamin B12 deficiency anaemia most commonly occurs when the vitamin cannot be
absorbed from food or supplements. This can happen if:
 You have pernicious anaemia – where the stomach does produce any intrinsic factor due to autoimmune damage of the cells lining the stomach.  You have had a partial or total removal of your stomach or other gut surgery.  You have a digestive problem like coeliac disease or Crohn’s disease, bacterial over growth in the small intestine or a parasitic infestation.  You take medication such as metformin (used to treat diabetes), neomycin (an antibiotic), cimetidine, ranitidine and omeprazole (used to treat heart burn and stomach ulcers).
More rarely, people who don't have enough vitamin B12 in their diet develop B12
anaemia. Those at risk include people who follow a vegan or strict vegetarian diet,
older adults who don't eat a variety of foods, and people with chronic alcoholism.
Deficiency symptoms
People with mild vitamin B12 deficiency may not have any symptoms or they may go
un-noticed. If the anaemia becomes worse, they may be:
 Weakness, fatigue, and lightheadedness  Nausea, decreased appetite, and weight loss If the level of vitamin B12 stays low for a long time, it can cause serious nerve damage, which may be irreversible. This can lead to:  Numbness or tingling in the hands and feet 40 Bowling Green Lane, London, EC1R 0NE
Tel: +44 (0) 20 7415 7070 Fax: +44 (0) 20 7415 7074 Mobile +44 (0) 7958 913772
Email: tony@peoplematter.tv Web site www.nigeldenby.co.uk
The Denby Report on Vitamin B12 deficiency
First Published Healthspan Feb 2010
Page 3 of 4

Treating B12 deficiency
Regular intramuscular injections of vitamin B12 or oral supplements are used to treat
B12 deficiency. The dose is quite high – 1000mcg is injected every 2 – 3 months.
Research consistently shows that cobalamin deficiency can be effectively treated by
oral or sublingual administration of cobalamin or a vitamin B complex.
Sublingual literally means ‘under the tongue’ – whereby tablets are placed under the
tongue and held there until dispersed. This usually takes about 10 minutes. Many
cardiovascular drugs, steroids and enzyme preparations are administered
sublingually. The skin under the tongue, called the buccal mucosa, contains a high
density of blood vessels – this aids the rapid absorption of the substance into the
blood stream where it can be distributed throughout the body.
There are many benefits to sublingual administration of vitamin B12:
 People who lack intrinsic factor can receive the vitamin by this route instead  This route is very quick – some drugs appear in the circulation within 1 or 2  Avoids exposure to the harsh stomach environment – where some substances may be metabolised or destroyed.  People with gastrointestinal difficulties can benefit from sublingual vitamin  Elderly people with reduced intrinsic factor secretion can increase their  Ideal for people who find swallowing tablets difficult. 40 Bowling Green Lane, London, EC1R 0NE
Tel: +44 (0) 20 7415 7070 Fax: +44 (0) 20 7415 7074 Mobile +44 (0) 7958 913772
Email: tony@peoplematter.tv Web site www.nigeldenby.co.uk
The Denby Report on Vitamin B12 deficiency
First Published Healthspan Feb 2010
Page 4 of 4

Key points
Most people following a varied, balanced diet who include animal foods such as
meat, fish, eggs and cheese will get enough vitamin B12 to meet their needs.
People following a vegan diet need to ensure they include fortified foods in their diet.
Most cases of vitamin B12 deficiency are caused by an inability to absorb the vitamin
due to a lack of production of intrinsic factor in the stomach or other problems with
the gut that limits absorption.
High dose supplements or intramuscular injections are used successfully to treat
vitamin B12 deficiency
If you answer yes to any of these questions you may be at risk of vitamin B12
deficiency.
Are you a vegan or strict vegetarian?
Are you over the age of 65?
Do you have coeliac or Crohn’s disease?
Have you had extensive gut surgery?
40 Bowling Green Lane, London, EC1R 0NE
Tel: +44 (0) 20 7415 7070 Fax: +44 (0) 20 7415 7074 Mobile +44 (0) 7958 913772
Email: tony@peoplematter.tv Web site www.nigeldenby.co.uk

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