Vitamin B12 Deficiency



Incidence of Vitamin B12 Deficiency


Vitamin B12 deficiency is arguably the most under-diagnosed condition in the community, however the incidence of vitamin B12 deficiency can be very high, particularly in some groups and country of origin.


A study by Dr Bevan Hokin on various populations in Australia found that vitamin B12 deficiency (defined as less than 220 pmol/L) varied depending upon diet and age as follows:




Vegans (depending upon duration)


Elderly in Assisted care



The frequency of deficiency varies from country to country and is very high in some countries.




pmol/L cut-off


School Age Children





Nepal (pregnant women)



Nigeria (adolescent girls)



Sweden (elderly)






United Kingdom



United Kingdom (pregnant women)



United Kingdom (pregnant women)





















Vietnam (2005)




It should be noted that biochemically vitamin B12 deficiency can be measured when levels of B12 are below 250 pmol/L so the actual biochemical B12 deficiency will be much higher for countries such as Turkey, Spain, India, Venezuela, Nepal, Kenya, Canada and even the United Kingdom. The frequency of vitamin B12 deficiency is likely to increase as more omnivores switch to eating more low vitamin B12 containing meats such as chicken, and even in traditionally red-meat eating countries such as Australia the consumption of chicken is now greater than combined beef and lamb consumption. In the US, consumption of red meat has been steadily declining since is peak in 1972, whilst chicken consumption has increased dramatically since 1944 (curiously paralleling the rise in both obesity and autism seen in that country over the same period).


Consequences of Vitamin B12 Deficiency


Vitamin B12 deficiency as multiple effects throughout life. Vitamin B12 deficiency in mothers has been associated with premature birth, small for age babies, developmental delay in the off-spring and autism. Vitamin B12 deficiency that develops later in life can be associated with poor gut health, fatigue, brain fog, loss of memory, histamine intolerance, anaemia and many other symptoms. Prolonged vitamin B12 deficiency can even lead to brain shrinkage later in life.


The most common symptom of vitamin B12 deficiency is fatigue, but it is also associated with IBS, restless leg syndrome, mood swings, apathy, lack of motivation, difficulty sleeping, incontinence, impotence, loss of libido, amongst other things.


The degree of deficiency is associated with more and more symptoms. We have developed a symptom form, which can be provided by request.




Allen, JH 2009 How common is vitamin B12 deficiency? Am J Clin Nutr 89:693-6

Dupuy HF 1984 The psychological general well-being index. In. Wenger, N et al. Assessment of quality of life. Le Jac1 Publishing 1984

Herbert V. 1996 Vitamin B12. In. Present knowledge in nutrition (7th Ed). Olsen RE ed. International Life Sciences Institute V20: 191-204

Hokin BD 2003 Vitamin B12 deficiency issues among selected at-risk populations. PhD Thesis

McLean, et al, 2008 Review of the magnitude of folate and vitamin B12 deficiencies worldwide. WHO fold an nutrition bulletin, 29:2

Tucker et al 2000 Plasma vitamin B12 concentrations relate to intake source in the Framingham Offspring Study. Am J Clin Nutr, 71:514-22

Vogiatzoglou et al. 2008 Vitamin B12 status and rate of brain volume loss in community-dwelling elderly. Neurology 71, 826-32

Daniel et al. 2011 Trends in meat consumption in the United States Pub Health Nutr. 14, 575-583

Baltaci et al Evaluation of serum vitamin B12 level and related nutritional status among apparently healthy obese female individuals. NJCP 2017 20: 99-105

Knight et al Lower circulating B12 is associated with higher obesity and insulin resistance during pregnancy in a non-diabetic white British population. PLos One 2015 10:e0135268




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The statements on this site compose a compendium of generally recognized signs of vitamin B12 deficiency, and problems that can then ensue They also are formulated from a summary of relevant scientific publications. In addition they may contain some forward looking statements of a general nature.
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