Vitamin B12 and Mental Health: An Expert Series

James Greenblatt, M.D.

March, 2023

People take supplements to improve or optimize their health. So what happens when you look at the label, and the ingredient list is filled with unrecognizable additives?

As a nutrient, vitamin B₁₂ has several important roles, including contributing to the maintenance of healthy brain function. As a partner to folate, vitamin B₁₂ is also important for transferring and supplying what are called “single carbon units” or methyl groups. Transferring methyl groups through the process of methylation is critical for the formation of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), neurotransmitters and the protective casing or sheath that surrounds nerve cells called myelin.

As a player in normal cognitive functioning, vitamin B₁₂ has a role in supporting mental health. A deficiency in B vitamins is known to be associated with low mood and cognition. A recent analysis even suggests that vitamin B₁₂ supplementation may support positive mood.¹

Along with potentially supporting emotional health, vitamin B₁₂ can be critical for supporting healthy cognitive function. Studies on supporting cognitive health due to low vitamin B₁₂ are prevalent in the published research.² Due to these benefits, an international consensus statement published in 2018 recommends B-vitamin supplementation for maintaining brain health and cognitive function when appropriate.³

Part of the benefits of vitamin B₁₂ for supporting healthy brain function likely stem from its effects on homocysteine. Homocysteine is an amino acid formed in the body during healthy functioning. Typically, levels of homocysteine are kept low by vitamins B₁₂, folate and vitamin B₆. However, if levels of these B vitamins are inadequate, homocysteine levels can build up.

Clinical studies show that vitamin B₁₂ is vital in the metabolism of homocysteine. Vitamin B₁₂is required by the enzyme that converts homocysteine back to methionine.⁴ Vitamin B₁₂, in combination with vitamin B6, folate, and betaine can provide a highly bioavailable combination of nutrients integral to maintaining healthy homocysteine metabolism and cardiovascular health.⁵

Another key factor in vitamin B₁₂’s ability to support healthy brain function is its role in neurotransmitter production. Vitamin B₁₂, like folate, is needed for the production of serotonin, norepinephrine and dopamine. Standard support for regular low mood often targets these neurotransmitters. As such, serotonin is often described as the “feel good” neurotransmitter of the brain. By supporting the production of these neurotransmitters, vitamin B₁₂ plays a significant part in healthy brain function.

Vitamin B₁₂ is found in a number of foods, although mostly of animal origin, including liver, seafood, beef, dairy products and eggs. Vegetarians often do not get enough vitamin B₁₂ and typically need to supplement the vitamin. For supplementation, the active forms of vitamin B₁₂ are often preferred, including methylcobalamin and adenosylcobalamin, although hydroxycobalamin is readily converted as well.

As a nutrient, vitamin B₁₂ plays a crucial role in healthy brain function that supports mental health. Research suggests benefits that may be relevant for helping to support both healthy cognition and mood.

Ask The Expert

Should I take vitamin B₁₂?

Dr Greenblatt- It depends. Having low B₁₂ is quite common and while standard labs may help in identifying individuals who may need the vitamin, they don’t directly measure levels reaching the brain. Vegans and vegetarians typically need supplementation, and it likely should be considered for individuals in need of support for emotional wellbeing and cognition.

I am a vegan and heard seaweed is a good source of vitamin B₁₂. Is that true?

Dr Greenblatt- Some data suggests that nori, a type of seaweed, shiitake mushrooms and soy yogurt might provide vitamin B₁₂. However, studies of long-term consumption of these foods for maintaining adequate levels in humans have not been performed. It may be worth considering supplementation or the consumption of fortified foods to maintain adequate Vitamin B₁₂ levels.

Does vitamin B₁₂ support a healthy mood?

Dr Greenblatt- Vitamin B₁₂ helps to maintain a normal mood. If a person is not consuming adequate vitamin B₁₂, supplementation may be of benefit.

Can you get too much vitamin B12?

Dr Greenblatt- Vitamin B₁₂ supplementation is typically well tolerated with minimal, or only mild, side effects. While there is no official upper limit of safety, there are cases of side effects from higher doses of the vitamin. Side effects can include feeling wired or excessive energy, headache, nausea, diarrhea, skin rash and fatigue. If you are taking high doses and think you are having side effects, stop supplementation and consult with your primary care doctor. In some cases, switching forms of the vitamin may reduce or eliminate concerns.

A pioneer in the field of integrative medicine, James M. Greenblatt, MD, has treated patients since 1988. After receiving his medical degree and completing his psychiatry residency at George Washington University, Dr. Greenblatt completed a fellowship in child and adolescent psychiatry at Johns Hopkins Medical School. Dr. Greenblatt currently serves as the Chief Medical Officer at Walden Behavioral Care in Waltham, MA and serves as an Assistant Clinical Professor of Psychiatry at Tufts University School of Medicine and Dartmouth College Geisel School of Medicine.

An acknowledged integrative medicine expert, educator, and author, Dr. Greenblatt has lectured internationally on the scientific evidence for nutritional interventions in psychiatry and mental illness. Through three decades of practice and research, Dr. Greenblatt is a leading contributor to helping physicians and patients understand the role of personalized medicine for mental illness. To learn more about the author, please visit www.JamesGreenblattMD.com.

+The views expressed in this article are those of the authors. They do not reflect the opinions or views of Pure Encapsulations®.

References

Borges-Vieira JG, Cardoso CKS. Nutr Neurosci. 2022;1-21. doi:10.1080/1028415X.2022.2031494
Sashindran VK, Aggarwal V, Khera A. Med J Armed Forces India. 2022;78(1):94-98. doi:10.1016/j.mjafi.2020.11.003
Smith AD, Refsum H, Bottiglieri T, et al. J Alzheimers Dis. 2018;62(2):561-570. doi:10.3233/JAD-171042
Halsted CH, et al. Proc Natl Acad Sci USA. 2002 Jul 23;99(15):10072-7.
O’Leary F, Samman S. Nutrients. 2010 Mar;2(3):299-316. doi: 10.3390/nu2030299. Epub 2010 Mar 5. PMID: 22254022; PMCID: PMC3257642.