B12 Deficiency and Mental Wellbeing

B12 Deficiency and Mental Wellbeing

Vitamin B-12, or Cobalamin, is the largest and most complex vitamin.  It is water soluble. B12 deficiency is very often very difficult to diagnose. Tests don’t always tell you what’s actually going on.

Vitamin B12 deficiency can lead to anaemia, fatigue, mania, and depression, while a long-term deficiency can cause permanent damage to the brain and central nervous system. People who have a B12 deficiency are frequently misdiagnosed as having Alzheimer’s disease, dementia, multiple sclerosis, heart disease, learning disability, Parkinson’s disease, depression, or other mental illnesses.2

B12 deficiency can be present without the anaemia. Your body needs Vitamin B12 (cobalamin). It promotes your body’s use of iron and activates enzymes that regulate the level of homocysteine that you have in your blood. High levels of the amino acid homocysteine may increase your risk of heart disease and affect your mood.

Folate and vitamin B12 are major determinants of one-carbon metabolism, in which S-adenosylmethionine (SAM) is formed. SAM donates methyl groups that are crucial for neurological function. Increased plasma homocysteine is a functional marker of both folate and vitamin B12 deficiency. Increased homocysteine levels are found in depressive patients. In a large population study from Norway increased plasma homocysteine was associated with increased risk of depression but not anxiety.1

Neuropsychiatric symptoms are among the most common presenting signs of vitamin B12 deficiency yet the diagnosis is often missed because of lack of awareness of this condition among clinicians 3(Lachner et al., 2012)

In the 1980s, researchers showed that almost one-third of patients with the neuropsychiatric symptoms of vitamin B12 deficiency had no anaemia or macrocytosis 4(Lindenbaum et al., 1988).

B12 must be regularly acquired from the intake of animal proteins or fortified cereal products. Gastric acid frees vitamin B12 from animal proteins, after which it mixes with intrinsic factor produced by gastric parietal cells and is absorbed in the terminal ileum.

A person can have B12 deficiency from having crohn’s disease, a gastric bypass or surgery, coeliac disease, or dietary causes does not have pernicious anaemia. However, we all need to understand that whatever the cause of the B12 deficiency it can be deadly or pernicious if not diagnosed and treated.   Pernicious is defined as “deadly, fatal, malignant, damaging, highly injurious or destructive.

A recent study suggests that methylcobalamin form of vitamin B12 may serve as an effective inhibitor of the nsp12 protein in Sars Cov2.1

Some alcohol and medications inhibit the absorption of B12. These include ranging from gastro-esophageal reflux (GORD) drugs (Ranitidine, Cimetidine, Pepcid and antacids), Metformin, Colchicine, Omeprazole, Lansoprazole, Neomycin, Phenytoin, Potassium chloride, Cholestyramine, Statins and Oral Contraceptives.

Please read Chapter 8 of Vitamin B12 in Clinical Practice for more on Neuropsychiatric disorders, including dementia – prevention is better than cure. 5

It is clear that we need  to  increase awareness of B12 deficiency and ensure it is correctly understood, diagnosed and treated.

Written by Annie Barr MBE  

MA, BSc Hon’s RGN, PGCert, INP, ANP,   EPA Clinical Director,  AB Health and Wellness

Contact: annie@abhealthandwellbeing.com

References and further reading

1Vitamin B12 may inhibit RNA-dependent-RNA polymerase activity of nsp12 from the SARS-CoV-2 virus

Naveen Narayanan Deepak T Nair  https://pubmed.ncbi.nlm.nih.gov/32812340/

2Alec Coppen Christina Bolander-Gouaille J Psychopharmacol 2005 Jan;19(1):59-65.doi: 10.1177/0269881105048899.

3 Lachner, C., Steinle, N.I. and Regenold, W.T. (2012) The Neuropsychiatry of Vitamin B12 Deficiency in Elderly Patients. The Journal of Neuropsychiatry and Clinical Neurosciences, 24, 5-15.  https://doi.org/10.1176/appi.neuropsych.11020052

 4 Lindenbaum et al., 1994; Baik and Rusell, 1999; Carmel, 2000; Chui et al., 2001; Clarke et al., 2003, 2004; Loikas et al., 2007.

5 Vitamin-B12-Deficiency-Clinical-Practice/dp/1090400810 Chandy J 2019, Minney, Hugo  available on amazon https://www.amazon.co.uk/Vitamin-B12-Deficiency-Clinical-Practice/dp/1090400810

6ROBERT C. LANGAN, MD, and KIMBERLY J. ZAWISTOSKI, DO, St. Luke’s Hospital, Bethlehem, Pennsylvania Am Fam Physician. 2011 Jun 15;83(12):1425-1430.

Recommended Resources

Could It Be B12?: An Epidemic of Misdiagnoses (Paperback) by Sally M. Pachlok, Jeffrey J. Stuart

Evatt ML, Mersereau PW, Bobo JK, Kimmons J, Williams J. Centers for Disease Control and Prevention. Why vitamin B12 deficiency should be on your radar screen. http://www.cdc.gov/ncbddd/b12/index.html. accessed 2021


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