Vitamin B12 Deficiency – An Issue of Widespread Concern

Do you often get ‘pins and needles’ and suffer from a lack of energy or fatigue? Well it could be something that you may not yet have considered – Vitamin B12 deficiency.

Vitamin B12 is one of the most documented and researched nutrient deficiencies in medical science, yet despite this it still prevails on a frequent level in the UK – “affecting around 1 in 10 people above the age of 75” as reported by the NHS. However, it is considered by many doctors that this statistic may actually be closer to ‘1 in 4’.

In this article we look into the most common causes behind vitamin B12 deficiency and also the complications – if left untreated – that a deficiency in this essential nutrient can cause.

What is Vitamin B12?

Vitamin B12 is one of the eight ‘B-Complex’ vitamins necessary for the normal functioning of the nervous system and is considered to be the single most important factor in the maintenance of the nerves.

Vitamin B12 is involved in the metabolism of every cell in the human body. It plays a key role in DNA synthesis and formation, red blood cell creation, and brain function.

The human body is unable to naturally synthesize vitamin B12, so it must be consumed from the diet or a form of supplementation. The human digestive tract may have B12-producing bacteria; however, dietary B12 is the best way to ensure adequate nutrition.

Vitamin B12 Deficiency Symptoms

The human body’s absorption of vitamin B12 appears to decrease with age and therefore low levels of vitamin B12 are more likely to be identified in people over 50.

The Harvard Health Blog  have summarised some of the most common signs and symptoms of vitamin B12 deficiency:

“Vitamin B12 deficiency can be slow to develop, causing symptoms to appear gradually and intensify over time. It can also come on relatively quickly. Given the array of symptoms it can cause, the condition can be overlooked or confused with something else. Symptoms may include:

  • Strange sensations, numbness, or tingling in the hands, legs, or feet
  • Difficulty walking (staggering, balance problems)
  • Anaemia
  • A swollen, inflamed tongue
  • Yellowed skin (jaundice)
  • Difficulty thinking and reasoning (cognitive difficulties), or memory loss
  • Paranoia or hallucinations
  • Weakness
  • Fatigue”

Possible Causes of a Vitamin B12 Deficiency

The liver stores enough vitamin B12 to last several years, and any conditions that may lead to vitamin B12 deficiency is likely to have been ongoing for around 2 or 3 years before symptoms would appear.

Vitamin B12 is bound to animal protein when it is ingested at which point it is released by gastric acid. Beyond this point, vitamin B12 binds to Intrinsic Factor which is a protein that allows the nutrient to be absorbed.

The absorption and methylation of B12 is an extremely complex process which leaves many opportunities for error.  For this reason, even adequate consumption of vitamin B12 can result in the possibility of deficiency. This can be down to several factors.

Intrinsic Factor

When bound to Intrinsic Factor, B12 will survive the journey through the stomach and reach the small intestine. Without Intrinsic Factor, vitamin B12 would not survive the levels of acidity in the stomach.

Once the small intestine has been reached, Intrinsic Factor dissolves, releasing B12 to bind with another protein named transcobalamin II which the transports the nutrient into the bloodstream, and then on to the liver.

Only the parietal cells of the stomach create enough Intrinsic Factor to supply the body with adequate B12. When these cells are in any way damaged – or inhibited by a form of medication – Intrinsic Factor cannot be produced and therefore vitamin B12 isn’t able to be absorbed.

Ulcerative gastritis and a high intake of alcohol and can cause the parietal cells to die and this, in turn, greatly increases the chances of developing a B12 deficiency.

The absence of intrinsic factor can lead to a condition called pernicious anaemia, or the inability to initiate intrinsic factor and B12 absorption. In some cases, pernicious anaemia can be passed down through families. It is the most common form of Vitamin B12 deficiency and more likely to occur in those over 60, women and those with a genetic predisposition.

Signs of Pernicious anaemia include:

  • Shortness of breath
  • Fatigue
  • Palpitations

 Low Levels of Stomach Acid

Another common cause of vitamin B12 deficiency, especially in the elderly, is a lack of stomach acid, because stomach acid is required for the process of releasing vitamin B12 from food. Recent research has backed up this claim:

“In elderly persons in the Framingham Offspring Study, 24% of those aged 60–69 y and 37% of those aged ≥80 y had elevated serum gastrin. Likewise, in the SALSA Study, serum gastrin was elevated in 48% of the elderly participants with deficient plasma vitamin B-12 values, in 23% of those with marginal concentrations, and in 21% of those with normal status; overall, these concentrations were inversely correlated with plasma vitamin B-12.”

People who frequently take medication that destroys stomach acid—for example H2 blockers and proton-pump inhibitors (one of the most commonly prescribed medications)—are likely to have difficulty absorbing vitamin B12 from food.

 Recommended Daily Allowance (RDA) Inadequate

A range of health experts believe that the European recommended daily allowances (RDA’s) for B-Vitamins and particularly B12 are much too low. The same debate continues regarding RDA’s for other vitamins and minerals too, for example Vitamin D intake. Indeed the dosage of a lot of B12 supplements on the market is 500ug (per tablet) and this would be in line with many health practitioners’ recommendations as a typically suitable intake for many in the adult population.

‘Sublingual’ Vitamin B12 is becoming an increasingly popular option to supplement with. Sublingual literally means ‘beneath the tongue’ and these tablets will quickly dissolve in the mouth and rapidly allow the Vitamin B12 to be absorbed into the blood vessels and thus avoid the problems associated with digestive tract uptake.

‘Form’ of Vitamin B12 – Methylcobalamin vs Cyanacobalamin

There are two main ‘forms’ of vitamin B12 that you are likely to have come across – cyanocobalamin and methylcobalamin. The former is much more common in supplement form however the latter is better absorbed by the body.

There is a slight chemical difference between the two; methylcobalamin has a methyl group attached and cyanocobalamin has a cyanide group.

Cyanocobalamin is an inactive form of vitamin B12 and exists only via chemical supplementation. It is not present in nature, meaning your body does not metabolically recognise it and absorption is much less efficient.

Your body actually has no use for the cyano- compound found in cyanacobalamin, and looks to convert it into active methylcobalamin as soon as possible. It is the methyl- compound that the human body needs to function properly.

Not only does this mean that cyanocobalamin is a much less efficient form of supplementation of vitamin B12, but your body also has to ‘deal’ with cyanide group that is liberated during conversion into methycobalamin.

Although the levels of cyanide are rarely at a level to have a detrimental or serious impact in your health, it is still a poison and it is essential that it is removed from your body as soon as possible. This is a particular problem for those with errors of detoxification enzymes when the cyanide component is not removed and accumulates leading to toxic overload.

So the question is; why is cyanocobalamin more common in the pharmaceutical industry? The answer is of course; money. Synthesizing the unnatural cyanocobalamin form is a far cheaper alternative to obtaining methylcobalamin.


Hydroxycobalamin is another lesser known inactive form of vitamin B12. It has a similar efficacy to cyanocobalamin as it is also converted into active methylcobalamin in the body.

However it differs to cyanocobalamin because the structure does not contain a toxic group therefore the detoxification process is not required.

In addition, in comparison to cyanocobalamin, hydroxycobalamin has a much higher affinity to plasma proteins. This property helps to retain the hydroxy-protein complex in the blood stream for a much longer period of time.

Hydroxycobalamin may be important to begin with if one has both a folate and a vitamin B12 deficiency in order to prevent permanent central nervous system damage. Methylcobalamin cannot fulfil this role on its own whereas hydroxycobalamin is able to convert to multiple forms therefore has multiple purposes.

Please note that Hydroxycobalamin is the INJECTABLE form of vitamin B12. It is very rarely found in a tablet or capsule form as it is extremely difficult to stabilise.

Food Sources of B12 – Vegans and Vegetarians at risk?

Vegans and vegetarians are often at risk of vitamin B12 deficiency as the vitamin is mainly found in animal based foods such as meats and offal. The Vegan Society comments “Very low B12 intakes can cause anaemia and nervous system damage. Most vegans know that B12 deficiency can cause neurological complications and tingling sensations or numbness.” The link to the Society page on B12 is below and excellent and informative reading for everyone whether on dietary restrictions or not.

The water solubility of the B-Complex vitamins means that any excess is excreted and not stored (e.g. excreted by going to the toilet or sweating); therefore they must be continually replaced. This is a key point to make with problems relating to Vitamin B12 deficiency. Symptoms of deficiency can typically take between 3 to 5 years to manifest themselves as, uniquely among B vitamins, a supply of B12 is stored in the liver. Symptoms are generally only apparent once the reserves in the liver have become depleted. Hence at this stage someone is significantly low in B12 and this needs addressing rapidly to ensure no permanent nerve damage occurs.

Genetic Factors

Despite dietary and lifestyle choices being pivotal when it comes to particular nutritional deficiencies, it is also true that genetic predisposition can also play a part.

Cellular Uptake Mutations: Certain genetic mutations can cause inefficient cellular metabolism of vitamin B12. A genetic disorder of B12 metabolism allows normal intestinal absorption of vitamin B12 and normal blood levels, but the cells cannot metabolize the vitamin after uptake.

Since a variety of different enzymes within the cell require vitamin B12 to function properly, too much or too little of any of these enzymes will cause a metabolic deficiency of vitamin B12.

Transcobalamin Mutations: Transcobalamin is a protein that is  present in your blood and that binds to vitamin B12. It plays a role in transporting vitamin B12  to all of the cells in your body.

If you have a genetic mutation that doesn’t allow the formation of transcobalamin, then cells will not be able to receive any vitamin B12 and a deficiency will result. Additionally, genetic defects may be present that provide transcobalamin but do not allow its uptake by the cells, causing B12 deficiency.

Complications with Vitamin B12 Deficiency

Brain Shrinkage

Vitamin B12 deficiency and with it the possibility of raised homocysteine levels can lead to brain atrophy (shrinkage). Brain shrinkage usually occurs alongside the normal process of aging however it is accelerated in the presence of neurodegenerative diseases such as Alzheimer’s – as we have discussed in previous blogs.

Medical News Today highlighted research that suggests a lack of vitamin B12 contributes significantly to brain atrophy:

“Christine C. Tangney, Ph.D. and team carried out a study with 121 individuals aged at least 65 years from the south side of Chicago. They underwent blood tests to check for their levels of B12 and B12-related metabolites which can give an indication of a B12 deficiency. They were also assessed for memory and other cognitive skills. About four-and-a-half years later magnetic resonance imaging (MRI) scans of their brains were taken to see how big their brains were, as well as identifying some other signs of brain damage.

Those with four of five markers for vitamin B12 deficiency were found to have a higher risk of getting lower cognitive test scores and smaller total brain volumes.”

An increased level of homocysteine in the blood is also an independent risk factor for strokes and other chronic diseases due to its ability to increase inflammation – Please see previous blog – Elevated Homocysteine (link) – for more information.

Foetal Development

Vitamin B12, as well as Folate, play pivotal roles in brain development, especially during foetal development and the first two or 3 years of a child’s life.

It is important that pregnant women who have a folate or a vitamin B12 deficiency supplement in order to prevent the onset of any neurological complications.

Peripheral Neuropathy

Peripheral Neuropathy is commonly associated with vitamin B12 deficiency. In this condition there is a disruption in the transmission of nerve signals between the spinal chord and other areas of the body. This may be down to direct damage caused to the nerves

The symptoms are tingling sensation, pain and numbness. Depending on the type of the nerve affected, there can be loss of sensation or muscle mass and activity. This condition also needs early treatment to limit the damage and obtain effective results.


If not treated correctly a B12 deficiency, as we have mentioned, can lead to various conditions of differing severity. This highlights the importance of diet, and if possible, the correct form of supplementation.

The essential point to note, especially when it comes to supplementing vitamin B12, is that for necessary and efficient absorption it must be in the form of methylcobalamin – or occasionally hydroxycobalamin – as these are the only forms of B12 that the body is able to metabolise efficiently.

It is also essential – depending on your dietary preferences – to ensure good natural food sources of vitamin B12 and these include Fish, dairy products, organ meats (especially kidney and liver), eggs, beef and pork, pickles, nuts and seeds, yoghurts, miso, sourdough bread and soy sauce, ‘Marmite’, cheese and milk.

A deficiency in vitamin B12 is normally determined by a blood test and this is a very important step that everyone should consider in order to be certain that their levels are sufficient for optimal health. Medical professionals are fully aware of the importance of vitamin B12 and frequent tests for this nutrient are becoming more common. Although it is not something that is widely practiced – yet.

To conclude on a more general note, this article really is just the ‘tip of the iceberg’. Vitamin B12 – essential though it is – is just one nutrient that in the presence of a deficiency can have a detrimental affect on your health. But in truth, this is the case for all nutrients; they are pivotal for sustaining good health and in their absence we are at a much greater risk of illness. Without them our bodies cannot function at an optimal level.

If you have any questions regarding the health topics that have been raised, or any other health matters please do contact me (Amanda) by phone or email at any time., 01684 310099

Amanda Williams and the Cytoplan Editorial Team: Joseph Forsyth & Simon Holdcroft

 Relevant Blogs

Vitamin B12 Deficiency and Pernicious Anaemia

Elevated Homocysteine – A Risk Factor for Alzheimer’s Disease?

Relevant Products

Vitamin B12 Tablets – Sublingual Methylcobalamin – Our sublingual Vitamin B12 is at a higher potency of 500µg per tablet, and beneficially in the form of Methylcobalamin, and hence is universally bio-effective and ideal for vegetarians and vegans. Sublingual Vitamin B12 provides greater absorption as it avoids the problems associated with digestive tract uptake.


Last updated on 26th August 2015 by cytoffice


13 thoughts on “Vitamin B12 Deficiency – An Issue of Widespread Concern

  1. Really good article on what can easily become a serious problem for those
    less aware of dietary needs and it’s impact on health.

  2. A very informative article, written in a way that enables us to understand the structure of how ill-health can progress to the situation of totally different symptoms appearing.

  3. My daughter was deficient in B12 & was supposed to have 3 injections to rectify this. After 2 injections she broke out in very severe acne & refused to have the third injection. She is now reluctant to be tested even several years later. Do you have any suggestions on how to avoid another break out & is there any danger to supplementing without knowing whether there is a deficiency?

    1. Hi there,

      Thank you for your comments on this blog post.

      B12 deficiency is potentially a serious problem and really needs to be understood in individuals. What is causing the depletion, particularly in a young person? The cause needs addressing but I have to advise that if she has been deficient, that she does get tested again to understand her B12 status, and avoid neurological damage that can ensue from low B12 levels.

      My advice would be firstly to understand her B12 status. If she is very depleted then an injection followed by our sublingual B12 (adenosyl/methylcobalamin) daily would work well, and a single injection should not cause a break out.

      If she is only slightly low when tested then she could probably go straight onto the sublingual product at a higher dose for starters.

      I also recommend she is tested for folate and iron levels (haemoglobin and ferritins for the iron).

      It might also be a good idea for your daughter to take zinc as this will help prevent the breakouts and depending on cause, might also help to protect against the B12 deficiency she has experienced. But please do contact us if you would like comprehensive help on this problem

      Best wishes,

  4. I have the B12 deficiency and have injections every 12 weeks, it’s been a challenge to get my GP practice to give me the injection every 10 weeks. The last two weeks waiting are absolute energy very low not wanting to go out and enjoy retirement, why can’t doctors give their patents B12 when needed,I’m told it’s a Government initiative those who don’t have this illness make the rules,we are not all the same. As adults we are not daft,we know the signs as our families often say, having pernicious anaemia is a horrid illness, my mother was also ill with this although her condition was found to late. Sad really in other countries you can have the injection when needed,although they do have to pay, I’m sure many suffers would willingly pay in those last few weeks before their injection is allowed.

  5. On my nutritionist’s advice I have just started taking Vitamin D3(2,500iu) for low levels,
    I am also taking levothyroxine, candesartan, clopidogrel and lansoprazole
    In October 2016 I had the second half of my thyroid removed as papillary cancer was found during an ultrasound of my neck following a small stroke. This was followed by RAI . I am now very giddy, my doctor says it is crystals in the semicircular canals and she has prescribed prochlorperazine to be taken as necessary.Also doing exercises for my balance, which sadly are not helping.
    Since taking the Vitamin D3 and the prochlorperazine I have had terrible acid heartburn.
    Obviously I do not want to take anything extra before consulting my GP. I feel I rattle enough. Could any of these react with each other to cause the acid reflux or should I be taking them apart, together or what?
    I am an 83 year old female and am the sole carer for my 95 year old husband with Alzheimer’s .
    Any help please.

    1. Hi Jenny,

      Thank you for your query on our blog. I am sorry to hear of your problems with balance that doesn’t seem to be getting better and now acid reflux. With regard to acid reflux, and whether any of your medications could be contributing, I suggest you visit your GP and ask for a review – acid reflux is not listed as a side effect of the prochlorperazine but it is worth discussing with your GP who can also investigate other causes. With regard to the vitamin D, take it with your main meal. We do advise taking supplements 2 hours away from medication.

      If you would like some more help you might be interested in our free health questionnaire service – if you complete and return a health questionnaire which you can find at this link – we will send you some written diet and supplement advice. Your husband would be very welcome to complete a questionnaire as well. Alternatively we can put a copy (or copies) in the post to you.

      All the best,

        1. Hi Maggie,

          Thank you for your comment. In order for us to provide the best advice, it would be better if you emailed our in-house nutritional therapist and managing director, Amanda. Her email is:


  6. I had a gastric bypass in 2006 and was instructed to have B12 injections monthly. Do to pandemic I have missed my injections. I now have tingling and numbness in my hands and feet. As a result I now need injections daily for the next 10 days. What foods could I be adding to my diet.

    1. Hi Sharon,

      Thank you so much for your comment. Your need for B12 will be high due to your gastric bypass and the reality is that it is very difficult to get any significant levels from foods. The following foods contain some: fish, meat, eggs, dairy, and some foods are fortified with it. But it is likely that you will either need injections or supplements ongoing. If ever you are unable to get regular injections again you would be wise to supplement with tablets of methylcobalamin (the active form of B12) – at around 500ug/day or higher.

      I hope this helps.


  7. Savid Khan,
    My central nervous system was damaged by epilepsy, by using vitamin b 12 has helped me to restore mental health. But not sufficient so how can I can recover my mental health

    1. Hi Savid,

      Thank you for your comment on our blog. to enable us to help you more effectively, please complete our FREE health questionnaire here.


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