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Dr Sharma Diagnostics

Vitamin B12 Deficiency

Are you struggling with any of the following ?

Unexplained tiredness Foggy thinking and concentration
Breathlessness Ridged nails
Swollen or sore tongue Pins and needles
Balance problems or unsteadiness Tinnitus
Skin problems such as rosacea or psoriasis Mood swings
Hair loss Memory loss

If pregnant have a collection of these symptoms started or become worse?

This link to a page by the Pernicious Anaemia Society leads to a questionnaire that clarifies whether one should be suspicious of B12 deficiency and whether tests or treatment might be beneficial.

Dr Mark Porter, the well known media ‘doc’ published in The Times (Saturday September 15th 2012) what the Pernicious Anaemia Society here in the UK and many integrated doctors have been saying for decades – we have underestimated the role that vitamin B12 plays in our general wellbeing.

Vitamin B12 deficiency can cause a condition known as pernicious anaemia (PA). This is identified by red blood cells becoming larger (megaloblastic anaemia) although this can be caused by other factors. Vitamin B12 deficiency however may not show up as a megaloblastic anaemia and simply provide any number of the symptoms listed above. If untreated one of the more serious problems that can arise is irreversible nerve damage.

Vitamin B12 deficiency is often caused by a loss of activity in cells in the stomach (parietal cells) responsible for secreting a specialised protein called Intrinsic Factor (IF). This is vital to allow the small intestine to absorb vitamin B12. It is not uncommon as we age to lose this activity but other causes at younger ages include autoimmune disease that attacks these gastric cells or form antibodies that destroy the intrinsic factor. Other causes such as long term gastritis and infection are suspected but not yet established.

B12 deficiency can be caused by inadequate dietary intake – typical in vegans – but as many vegans are not B12 deficient it is not clear if deficiency is due to poor digestion of food generally or a lack of B12 in the diet.

Our bowel flora provide an amount of B12 and it is possible that deficiency is avoided despite IF deficiency because of good production by the micro flora in the gut.

B12 deficiency is also found in those with malabsorption issues. Some conditions may be well recognised and diagnosed such as Crohn’s disease, ulcerative colitis or other inflammatory diseases, but less conventional causes include altered bowel bacteria (bad flora, yeast overgrowth etc) or inflammation due to food intolerance, allergy and certain drugs.

Antacids of any type are particularly culpable because gastric acid is needed to release vitamin B12 bound to proteins in our food making them un-absorbable.

There is often a genetic connection to PA but persistent inflammation of the stomach lining through poor diet, excess alcohol and caffeine, the presence of the organism H.pylori may all be relevant.

Tests and Investigations

Your GP should be willing to run a
  • blood (serum) vitamin B12 test
  • and full blood count to look at the size of red blood cells.
Preferably the B12 test will be for
  • active B12’, holotranscobalamin,
but often the test is just a measure of total B12 which is not necessarily a good marker.

If the result indicate a low blood B12 then further tests for
  • anti-gastic cell antibodies and/or
  • anti-intrinsic factor antibodies
will follow to rule out PA.

Doctors and GP’s are advised that the ‘normal’ reference range of serum B12 in blood tests is between 180-1,000pmol/mL and that only deficiency needs to be treated. This is generally offered by intramuscular (IM) injection no more than once every three months. Recent research from Oxford University suggests that 300pmol/mL might be a more accurate lower limit. There is some suggestion that the ranges are not accurate and that 500pmol/mL might be a more accurate lower required limit(1,2)

There is a further problem with the current UK ‘normal’ or reference ranges. A ‘reference range’ is not indicative of an individuals actual need or even their usual level. It is a result reflecting their level at the time of the blood test and compared to a scale of a large cohort of blood samples taken from a random selection of the population – regardless of whether they had B12 deficient symptoms or not.

What if a persons, individual OPTIMAL level is 950 pmol/mL and yet their tested level is 190 pmol/mL? - they are in the normal reference range but functioning on 1/5th of their individual body’s required amount. So they are, in effect, deficient.

Also, was their sample taken soon after a meal with high B12 content such that a simple serum measurement may not be indicative on anything but their most recent meal?

Functional Tests and Investigations

If problems persist despite B12 treatments as listed below then a more integrated medical approach should be considered to look at other causes of your symptoms.

Functional testing goes beyond simply measuring levels of B12 and looks at markers indicative of B12 function. The best test is measuring a compound in a 24 hour urine sample called
  • Methymalonic acid (MMA).
MMA is made by cells when they do not have enough Vitamin B12. If MMA is high we know cells are deficient.

To complicate the picture, however, MMA may be raised when blood levels are normal. This would suggest there is a normal intake and absorption into the blood stream but there is either:
  1. poor absorption into cells or
  2. high usage in the cells.
Unfortunately there are no conventional and accepted tests to investigate such issues.

I speculate that we can measure chemicals and environmental toxins that might be stuck to cell receptors and so block absorption or activity of B12 (and other things). These tests are scientifically valid but their results have not been shown to correlate with receptor dysfunction so it is entirely a theoretical avenue of tests and treatment that I have found useful in my practice.
  1. DNA adducts
  2. Mitochondrial TLP site adducts
One should also consider investigation for stomach acid (HCl) production through a saliva test:
  • Salivary VEGF
which is low in many cases of low HCl production.
  • Comprehensive digestive stool analysis
identifies inflammation and digestive enzyme levels as well as looking at the presence of good and bad bowel flora. These are important steps when looking for the cause of B12 deficiency and at options for treatment especially if supplementation has not worked.

Lastly, the list of B12 deficiency symptoms is broad and covers such a wide array of problems that we must be careful and not assume all such complaints are caused by vitamin B12 deficiency alone. Broad testing for toxins as mentioned above and full nutritional testing may be needed.


Ensure you read online about B12 rich foods and eat plenty. It is also useful to take a probiotics to increase bowel flora numbers and activity – although those with IF deficiency may not benefit much.

A trial of vitamin B12 orally is considered safe although dosage is best advised by your GP or a nutritionist. If you are lacking IF then oral B12 may be of limited use. Oral spray may allow some absorption through the membranes in the mouth (the buccal mucosa) but it may be difficult to get enough in to correct deficiency.

Intramuscular or subcutaneous (IM/SC) injections are both a). a treatment and b). useful in diagnosis. If you have an injection and get better then B12 deficiency is more likely to have been a cause of your problems.

It is considered important to use methylcobalamin, or if that is not available use hydroxycobalamin. Some people seem to do better on hydroxycobalamin. Cyanocobalamin, another form, has to be converted and some people have a reduced capability to do that so have no benefit.

Unfortunately GP’s are bound by NICE guidelines and are reluctant to offer IM injections if the patient has a ‘normal’ serum result. Also, the guidelines say B12 is only needed every 3 months and often despite patients symptoms coming back sooner another ‘jab’ is denied regardless of whether your benefit from an injection only lasted a few days or less than 12 weeks.

Very Important - According to a recent paper by Prof V Devalia et al, if you have typical symptoms of B12 deficiency and yet your B12 is in the lower half of the accepted normal range you may well still have a deficiency. The paper encourages doctors to pay attention to patients symptoms and apply treatment regardless of whether the test results disagree with the medical picture.

The Mayo Clinic suggests that once deficiency has been restored a monthly 1000 mcg IM injection could be given monthly

It may help to provide these links to a GP who feels bound by the NICE ‘guidelines’. Hopefully you will be able to have a discussion with your GP about more frequent injection regardless of the test results if you benefit from B12 injections.

All that said it is so important that you read this link about side effects and risks and stop taking supplementation immediately as well as bringing to a doctors attention anything you feel might be related to Vit B12 use.

Private Treatment.

Private doctors are also bound to observe Good Practice and NICE guidelines but often, after discussion with your GP, may be able to offer more frequent B12 injections, at least initially as a trial to see if things improve.

IM or SC injections can be given at clinics or we can teach individuals to self-administer safely so treatment can be given at home.

Intravenous infusions of multivitamin, minerals and nutrients including B12 can have a very swift and longer lasting effect.

It is important to note that in the face of GP opposition to such treatments private doctors may be risking censure and may not be willing to prescribe against a GP’s wishes. This is important as you make a decision to seek private treatment as fees and tests can be expensive. My fees are shown in my Patient Information page on my website

If I can be of further help please don’t hesitate to come and see me by booking an appointment though 01202 744 747, option 1 or 3.

Dr Rajendra Sharma
June 2015

  1. Goodman M, Chen XH, Darwish D (Oct 1996). "Are U.S. lower normal B12 limits too low?". Journal of the American Geriatrics Society 44 (10): 1274–5. PMID 8856015.
  2. Mitsuyama Y, Kogoh H (Mar 1988). "Serum and cerebrospinal fluid vitamin B12 levels in demented patients with CH3-B12 treatment--preliminary study". The Japanese Journal of Psychiatry and Neurology 42 (1): 65–71. doi:10.1111/j.1440-1819.1988.tb01957.x.PMID 3398357.

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