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

What is it about?

The study of B12 supplementation in stroke survivors has been a topic of interest, with some studies suggesting that older age may contribute to the lack of improvement in participants' distress. However, other studies have found no significant effect on symptoms of depression in older individuals. The trials used in cobalamin and B6 supplements are not disclosed, making it difficult to determine their effectiveness. Different types of cobalamins follow different metabolic pathways, and the type of cobalamin used also restricts researchers' ability to compare results. Folate is another area of interest, with the trials not providing a rationale for using B12 alone, despite its potential to reduce homocysteine. Combining B12 with folic acid could mask B12 deficiency and potentially cause subacute cord degeneration and cognitive decline. Folic acid is not recommended for those with low B12 levels, and their close interrelationship makes combining them beneficial. However, when using folic acid as a folate supplement, there are two things to be aware of: first, folic acid is a synthetic substance formed of only minor components of folate, so the benefits of supplementing folate are not being explored when folic acid is used. Second, folic acid cannot pass the blood-brain barrier, so it cannot aid B12 in synthesising monoamines. It also competitively blocks the binding of natural folates to folate receptors, so high levels of folic acid can mask low levels of natural folates needed to support B12, potentially hindering B12 function within the brain. High levels of homocysteine were observed in those with mental illness, and by using B12 to lower homocysteine, there was a rationalized possibility of reducing symptoms of mental illness. However, Almeida et al (2010), Okereke et al (2015), and Roffman et al (2013) were able to reduce homocysteine, although Almeida et al (2010) was the only study with clear results. Roffman et al (2013) showed a low level of results and significant effects for the FOLH1 genotype, but no significant result overall. Patient group specific results have been found in some studies, such as Almeida et al (2011) and Roffman et al (2013), who found groups statistically significantly helped and whose symptoms were reduced by the supplementation of B vitamins. This method of treatment, particularly for stroke survivors, can reduce the burden of disease and reduce the cost of treatment to mental health services by preventing the need for more expensive, restrictive, or harmful interventions. Roffman et al (2013) found that the supplement was helpful in treating negative symptoms of schizophrenia in those with the specific genotype FOLH1, because this gene affects folate metabolism. However, it is important to acknowledge the finding, as it promotes individualized, patient-centered care as required within the Nursing and Midwifery Council's (NMC's) Code (2015).

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Photo by Michele Blackwell on Unsplash

Photo by Michele Blackwell on Unsplash

Why is it important?

The literature review focuses on double-blind randomized controlled trials (RCTs) examining the supplementation of B12 in the treatment or prevention of mental illness. The studies were conducted on older adults aged 60-75 years, with a focus on reducing negative symptoms and preventing symptoms of depression. The research was based on the Critical Appraisal Skills Programme's (CASP) tool for RCTs and the CONSORT Statement's 25-point checklist for reporting parallel group randomised trials. First literature of the type in UK.

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