Vitamin B12 and Mental Health
A deficiency of vitamin B12 can affect mood, emotions, sleep, and can result in psychiatric disorders. (Valizadeh & Valizadeh, 2011)
Roles of vitamin B12 in the brain:
- Required for the synthesis of neurotransmitters including serotonin and dopamine
- Required for the preservation of protective myelin sheath around neurons
- Important for homocysteine metabolism
Psychiatric manifestations of vitamin B12 deficiency include (Oh & Brown, 2003: Dommisse, 1991):
- agitation, restlessness, irritability
- depression, fatigue
- mild memory impairment
- panic/phobic disorders
- personality changes
Vitamin B12 and Depression
Depression is a symptom of vitamin B12 deficiency. (Hector & Burton, 1988) (Gaby).
- Vitamin B12 was found to be inversely correlated with depression scores in un-medicated depressed patients (Kapoor et al., 2017)
Low levels of Vitamin B12 are associated with:
- Higher scores on the Beck Depression Inventory (BDI) (Güzelcan & van Loon, 2009)
- Decreased efficacy of Fluoxetine for Depression (Mischoulon et al., 2000)
- Poorer responses to common depression treatment (Hintikka et al., 2003)
Vitamin B12 and Depression in Vegetarians
When comparing omnivores and vegetarians, it was found that vegetarians had (Kapoor et al., 2017):
- Significantly Lower Serum B12 levels
- Significantly Higher Methylmalonic Acid (MMA) levels
- Higher frequency of depression (31%) than omnivores (12%)
People with depression may have higher needs due to decreased vitamin B12 transport across the blood-brain barrier (Arora, Sequeira, Hernández, Alarcon, & Quadros, 2017), or because of increased breakdown of vitamin B12 in brain tissue (Gaby, 2011)
Low serum Vitamin B12, with low folate and high homocysteine levels, predicted a higher risk of depression in older adults (Kim et al., 2008)
The most common causes of vitamin B12 deficiency:
- vitamin B12-deficient diet
- vegetarianism or veganism
- decreased stomach acid production
- bacterial overgrowth in the small intestine
Vitamin B12 levels can be normal in blood tests but be deficient in the cerebral spinal fluid. (Prousky, 2015)
Top food sources of vitamin B12 by serving size:
- clams, mussels
Comprehensive food list:
Table 2. Some Food Sources of vitamin B12 (Vitamin B12, 2014)
Referenced Dietary Intakes
RDAs for vitamin B12 (mcg/day)
Adolescents 14-18 years: 2.4 (M) 2.4 (F)
Adults 19-50 years: 2.4 (M) 2.4 (F)
Adults 51 years and older: 2.4 (M) 2.4 (F)
Tolerable Upper Intake
Not establish due to low potential for toxicity.
1. Vitamin B12 Supplementation
- Amounts of vitamin B12 used in practice and research range from 1,000–5,000 IU a day in divided doses.
- The preferred form of vitamin B12 is methylcobalamin, due to its greater tissue retention (“Methylcobalamin”, 1998)
- Vitamin B12 is best absorbed in sublingual form.
- “Those strict vegetarians who eat no animal products (vegans) need supplemental vitamin B12 to meet their requirements” (Vitamin B12, 2014)
- Vitamin B12 supplementation may have the best clinical response when used in the context of anxiety and fatigue or depression (Prousky, 2015)
2. Vitamin B12 injections
- A typical injection regimen is 1000 mcg every 2 weeks.
- Patients who respond to vitamin B12 injections typically need ongoing injections to maintain symptom improvement (Gaby, 2011).
- Many anxiety patients benefit from B12 injections even though they have no clinical evidence of deficiency (Prousky, 2015).
- Daily 5 mg B12 injections for two weeks in men and women with normal serum B12 were found to improve appetite, mood, energy, and sleep to the 4-week follow-up (Ellis & Nasser, 1973).
SAFETY, SIDE EFFECTS
- The Institute of Medicine states that “no adverse effects have been associated with excess vitamin B12 intake from food and supplements in healthy individuals” (Vitamin B12, 2014).
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Dommisse, J. (1991). Subtle vitamin-B12 deficiency and psychiatry: A largely unnoticed but devastating relationship? Medical Hypotheses, 34(2), 131–140. https://doi.org/10.1016/0306-9877(91)90181-w
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Güzelcan, Y., & van Loon, P. (2009). Vitamin B12 status in patients of Turkish and Dutch descent with depression: A comparative cross-sectional study. Annals of General Psychiatry, 8(1), 18. https://doi.org/10.1186/1744-859X-8-18
Mischoulon, D., Burger, J. K., Spillmann, M. K., Worthington, J. J., Fava, M., & Alpert, J. E. (2000). Anemia and macrocytosis in the prediction of serum folate and vitamin B12 status, and treatment outcome in major depression. Journal of Psychosomatic Research, 49(3), 183–187. https://doi.org/10.1016/S0022-3999(00)00158-6
Hintikka, J., Tolmunen, T., Tanskanen, A., & Viinamäki, H. (2003). High vitamin B12 level and good treatment outcome may be associated in major depressive disorder. BMC Psychiatry, 3(1), 17. https://doi.org/10.1186/1471-244X-3-17
Kapoor, A., Baig, M., Tunio, S. A., Memon, A. S., & Karmani, H. (2017). Neuropsychiatric and neurological problems among Vitamin B12 deficient young vegetarians. Neurosciences (Riyadh, Saudi Arabia), 22(3), 228–232. https://doi.org/10.17712/nsj.2017.3.20160445
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