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Can supplementing vitamin B12 improve mental health outcomes?: a literature review

02 March 2024
Volume 29 · Issue 3


Low vitamin B12 has been associated with raised plasma homocysteines and the consumption of B vitamins has been shown to reduce homocysteines. Raised levels of homocysteines have been linked to causing symptoms of mental illness. B12 is also required in the synthesis of monoamines and is required to maintain neurological health.


This study reviews research into the effects of the supplementation of B12 in the prevention and recovery of mental illness, and the potentiation of psychotropic medication.


This literature review follows a systematic approach to searching databases CINAHL, EMBASE, Medline, and PsycINFO where 287 non-duplicated articles results were received. Appropriate articles were identified through title and abstract screening and inclusion and exclusion criteria were applied. Five articles were chosen to address the research question following critical appraisal. Thematic analysis was then conducted.


This review identified five randomised controlled trials into the supplementation of various doses of B12 in conjunction with folic acid and B6. The supplement was measured against post-stroke depression prevention, the reduction of symptoms of depression in woman with cardiovascular disease, the effect on negative symptoms in schizophrenia, the reduction and prevention of depression in older adults, and the potentiation of psychotropic interventions. The papers reviewed showed inconclusive results, but evidence to support sub-groups and specific high-risk groups. Strong evidence showed supplementation of B12, folic acid and B6 has high rates of preventing post-stroke depression.


The findings show that this area of research is still to be developed. The effects of B12 supplementation with other B vitamins on mental health have shown to be inconclusive. There is a case for its use to be considered within certain patient groups to aid recovery of mental health or in some high-risk patient groups. Recommendations are made for further research into high-risk groups of people that may have symptoms or symptoms that could be improved through the supplementation of B12.

The effects of nutrition on health have been long recognised, from James Lind conducting the first clinical trial by treating scurvy with citrus fruits in 1747 (Milne, 2012) to Korsakoff syndrome caused by thiamine deficiency most regularly associated with the long-term abuse of alcohol (Kopelman, 2022). Less commonly known is the relationship between vitamin B12 and illness, and the role it plays in supporting neurological and mental health. This article explains vitamin B12's role in mental health, and provides the background and rationale for investigating the potential role of vitamin B12 supplements in mental health.

The World Health Organization (WHO) (2014) defines mental health as a state of wellbeing, in which an individual recognises their own potential and has the ability to cope with normal life stresses and contribute to their community. Where there is an absence of this state of wellbeing mental illness can occur, in other words a disruption to thought, behaviour, emotions, and relationships as described by the International Classification of Disease (WHO, 2022). Mental illness is one of the main causes of the overall burden of disease (Vos et al 2015), so discovering effective treatments and preventing mental health issues is important to improve people's quality of life and reduce the burden of ill health.

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