A wealth of mechanistic and clinical data show that B12 plays important and complementary role in supporting the immune system



Vitamin B12

Vitamin B12 plays a vital role in the immune system through helping in the production of white blood cells. Vitamin B12 may act as an immunomodulatory factor and enhance the number of cytotoxic T cells against viral infections (Tamura et al. 1999, Gombart et al. 2020). Vitamin B12 may also be used as a therapeutic agent in sepsis and systemic inflammatory response syndrome (SIRS). Vitamin B12 may help to maintain the normal function of macrophages. It also has some anti-inflammatory effects such as regulating Nuclear factor-jB (NF-ŒB), a key activator of the pro-inflammatory pathways. It also has a proven role in bacteriostasis and phagocytosis (Romain et al. 2016).


Tamura, J., et al., 1999. Immunomodulation by vitamin B12: augmentation of CD8þ T lymphocytes and natural killer (NK) cell activity in vitamin B12-deficient patients by methyl-B12 treatment. Clinical and experimental immunology, 116(1), 28–32.


Gombart, A.F., Pierre, A., and Maggini, S., 2020. A review of micronutrients and the immune system-working in harmony to reduce the risk of infection. Nutrients, 12(1), 236.


Romain, M., et al., 2016. The role of Vitamin B12 in the critically ill-a review. Anaesthesia and intensive care, 44(4), 447–452.


Vitamin B12, along with vitamin B6 and folate, is involved in the immune functions through their involvement in nucleic acid and protein biosynthesis. Decreased availability of vitamin B12 for rapidly proliferating B lymphocytes is believed to result in an impaired antibody response to pneumococcal polysaccharide vaccine and synthesis of specific Ig(66,67) .


  1. European Food Safety Authority (2009) Scientific Opinion on the substantiation of health claims related to vitamin B12 and red blood cell formation (ID 92, 101), cell division (ID 93), energy-yielding metabolism (ID 99, 190) and function of the immune system (ID 107) pursuant to Article 13(1) of Regulation (EC) No 1924/2006 EFSA J 7, 1223.
  2. Wintergerst ES, Maggini S & Hornig DH (2007) Contribution of selected vitamins and trace elements to immune function. Ann Nutr Metab 51, 301–323.

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