THE ROLE OF VITAMIN B12 IN THE DIET – IMPACT ON THE BODY. A LITERATURE REVIEW

Aleksandra Simlat; Angelika Szwaj; Aleksandra Cieciora; Adrianna Świerzyńska; Natalia Jankowska; Mateusz Cieciora; Małgorzata Kawiorska; Julia Surowiec; Ilona Mariańska-Wiśniewska; Tomasz Puszkiel

doi:10.31435/ijitss.1(49).2026.4668

Authors

Aleksandra Simlat University of Technology and Humanities in Radom, Radom, Poland https://orcid.org/0009-0000-8949-5756
Angelika Szwaj University of Technology and Humanities in Radom, Radom, Poland https://orcid.org/0009-0007-4257-0844
Aleksandra Cieciora University of Technology and Humanities in Radom, Radom, Poland https://orcid.org/0009-0009-7999-4047
Adrianna Świerzyńska University of Technology and Humanities in Radom, Radom, Poland https://orcid.org/0009-0007-1451-3009
Natalia Jankowska University of Technology and Humanities in Radom, Radom, Poland https://orcid.org/0009-0000-3618-6247
Mateusz Cieciora University of Technology and Humanities in Radom, Radom, Poland https://orcid.org/0009-0008-0711-9377
Małgorzata Kawiorska University of Technology and Humanities in Radom, Radom, Poland https://orcid.org/0009-0000-3184-7659
Julia Surowiec University of Technology and Humanities in Radom, Radom, Poland https://orcid.org/0009-0009-3356-8261
Ilona Mariańska-Wiśniewska Specjalistyczny Szpital Miejski im. M. Kopernika, Toruń, Poland https://orcid.org/0009-0007-1556-2910
Tomasz Puszkiel University of Technology and Humanities in Radom, Radom, Poland https://orcid.org/0009-0006-5413-7530

DOI:

https://doi.org/10.31435/ijitss.1(49).2026.4668

Keywords:

Vitamin B12, Cobalamin, Vitamin B12 Deficiency, Excess Vitamin B12

Abstract

Vitamin B12 is a key chemical compound for human health, involved in processes such as homocysteine methylation, DNA synthesis, and mitochondrial function. We present current knowledge on the causes and clinical significance of hypervitaminosis B12 and discuss cobalamin deficiency and excess in selected risk groups: pregnant women, vegetarians and vegans, athletes, and the elderly.

Aim of the study: The aim of the study is to assess the impact of vitamin B12 on the functioning of the human body. The analysis focuses on the role of vitamin B12 in the proper functioning of the nervous, hematopoietic, and cardiovascular systems. Furthermore, the study determines the effects of vitamin B12 deficiency and excess in the diet.

Material and methods: A literature review was conducted from the PubMed and Google Scholar databases. Key phrases as “vitamin B12”, “cobalamin”, “vitamin B12 deficiency” and “excess vitamin B12” were used.

Results and conclusions: Vitamin B12 plays a crucial role in the proper functioning of the human body, influencing the nervous, hematopoietic, and cardiovascular systems. Symptoms such as fatigue, anemia, and impaired concentration have been observed among individuals with vitamin B12 deficiency. The analysis revealed a significant correlation between vitamin B12 supplementation and bodily function. Therefore, it can be concluded that adequate levels of vitamin B12 in the diet are crucial for maintaining health.

References

Sobczyńska-Malefora, A., & Smith, A. D. (2022). Vitamin B-12. Advances in Nutrition, 13(5), 2061–2063. https://doi.org/10.1093/advances/nmac030

Halczuk, K., & Karwowski, B. (2022). Witamina B12 – czy jest nam potrzebna? Farmacja Polska, 78. https://doi.org/10.32383/farmpol/156953

Froese, D. S., Fowler, B., & Baumgartner, M. R. (2019). Vitamin B12, folate, and the methionine remethylation cycle-biochemistry, pathways, and regulation. Journal of Inherited Metabolic Disease, 42(4), 673–685. https://doi.org/10.1002/jimd.12009

Rzepka, Z., Słaby, D., & Wrześniok, D. (2021). Kobalamina – właściwości biomedyczne i niedobór w ujęciu biochemicznym. Advances in Hygiene and Experimental Medicine, 75, 563–572. https://doi.org/10.2478/ahem-2021-0004

Moravcová, M., Siatka, T., Krčmová, L. K., Matoušová, K., & Mladěnka, P. (2025). Biological properties of vitamin B12. Nutrition Research Reviews, 38(1), 338–370. https://doi.org/10.1017/S0954422424000210

Mucha, P., Kus, F., Cysewski, D., Smolenski, R. T., & Tomczyk, M. (2024). Vitamin B12 metabolism: A network of multi-protein mediated processes. International Journal of Molecular Sciences, 25(15), 8021. https://doi.org/10.3390/ijms25158021

Mathew, A. R., Di Matteo, G., La Rosa, P., et al. (2024). Vitamin B12 deficiency and the nervous system: Beyond metabolic decompensation-comparing biological models and gaining new insights into molecular and cellular mechanisms. International Journal of Molecular Sciences, 25(1), 590. https://doi.org/10.3390/ijms25010590

Wei, W., & Ruvkun, G. (2020). Lysosomal activity regulates Caenorhabditis elegans mitochondrial dynamics through vitamin B12 metabolism. Proceedings of the National Academy of Sciences of the United States of America, 117(33), 19970–19981. https://doi.org/10.1073/pnas.2008021117

Ge, Y., Zadeh, M., & Mohamadzadeh, M. (2022). Vitamin B12 regulates the transcriptional, metabolic, and epigenetic programing in human ileal epithelial cells. Nutrients, 14(14), 2825. https://doi.org/10.3390/nu14142825

Mantle, D., & Hargreaves, I. P. (2022). Mitochondrial dysfunction and neurodegenerative disorders: Role of nutritional supplementation. International Journal of Molecular Sciences, 23(20), 12603. https://doi.org/10.3390/ijms232012603

Green, R., & Miller, J. W. (2022). Vitamin B12 deficiency. In G. Litwack (Ed.), Vitamins and Hormones (Vol. 119, pp. 405–439). Academic Press.

Langan, R. C., & Goodbred, A. J. (2017). Vitamin B12 deficiency: Recognition and management. American Family Physician, 96(6), 384–389.

Ankar, A., & Kumar, A. (2024). Vitamin B12 deficiency. In StatPearls. StatPearls Publishing.

Green, R., Allen, L. H., Bjørke-Monsen, A. L., Brito, A., Guéant, J. L., Miller, J. W., Molloy, A. M., Nexo, E., Stabler, S., Toh, B. H., Ueland, P. M., & Yajnik, C. (2017). Vitamin B12 deficiency. Nature Reviews Disease Primers, 3, Article 17040. https://doi.org/10.1038/nrdp.2017.40

Sukumar, N., & Saravanan, P. (2019). Investigating vitamin B12 deficiency. BMJ, 365, l1865. https://doi.org/10.1136/bmj.l1865

Wong, C. W. (2015). Vitamin B12 deficiency in the elderly: Is it worth screening? Hong Kong Medical Journal, 21(2), 155–164. https://doi.org/10.12809/hkmj144383

Green, R. (2017). Vitamin B12 deficiency from the perspective of a practicing hematologist. Blood, 129(19), 2603–2611. https://doi.org/10.1182/blood-2016-10-569186

Shipton, M. J., & Thachil, J. (2015). Vitamin B12 deficiency: A 21st century perspective. Clinical Medicine, 15(2), 145–150. https://doi.org/10.7861/clinmedicine.15-2-145

Wolffenbuttel, B. H. R., Wouters, H. J. C. M., Heiner-Fokkema, M. R., & van der Klauw, M. M. (2019). The many faces of cobalamin (vitamin B12) deficiency. Mayo Clinic Proceedings: Innovations, Quality & Outcomes, 3(2), 200–214. https://doi.org/10.1016/j.mayocpiqo.2019.03.002

Saleem, A., & Tariq, M. (2024). Exploring the impact of vitamin B12 deficiency on central nervous system and cardiovascular health: A comprehensive overview. Scholars Bulletin, 10, 8–15. https://doi.org/10.36348/sb.2024.v10i01.002

Mathew, A. R., Cavallucci, V., & Fidaleo, M. (2023). Altered vitamin B12 metabolism in the central nervous system is associated with the modification of ribosomal gene expression: New insights from comparative RNA dataset analysis. Functional & Integrative Genomics, 23, Article 45. https://doi.org/10.1007/s10142-023-00969-6

Mathew, A. R., Di Matteo, G., La Rosa, P., Barbati, S. A., Mannina, L., Moreno, S., Tata, A. M., Cavallucci, V., & Fidaleo, M. (2024). Vitamin B12 deficiency and the nervous system: Beyond metabolic decompensation-comparing biological models and gaining new insights into molecular and cellular mechanisms. International Journal of Molecular Sciences, 25(1), 590. https://doi.org/10.3390/ijms25010590

Reynolds, E. H., Sobczyńska-Malefora, A., & Green, R. (2025). Fortification, folate and vitamin B12 balance, and the nervous system: Is folic acid excess potentially harmful? European Journal of Clinical Nutrition, 79, 1073–1077. https://doi.org/10.1038/s41430-025-01652-8

Green, R. (2017). Vitamin B12 deficiency from the perspective of a practicing hematologist. Blood, 129(19), 2603–2611. https://doi.org/10.1182/blood-2016-10-569186

Konda, M., Godbole, A., Pandey, S., & Sasapu, A. (2019). Vitamin B12 deficiency mimicking acute leukemia. Baylor University Medical Center Proceedings, 32(4), 589–592. https://doi.org/10.1080/08998280.2019.1641045

Pawlak, R. (2015). Is vitamin B12 deficiency a risk factor for cardiovascular disease in vegetarians? American Journal of Preventive Medicine, 48(6), e11–e26. https://doi.org/10.1016/j.amepre.2015.02.009

Mohan, A., Kumar, R., Kumar, V., & Yadav, M. (2023). Homocysteine, vitamin B12 and folate level: Possible risk factors in the progression of chronic heart and kidney disorders. Current Cardiology Reviews, 19(4), e090223213539. https://doi.org/10.2174/1573403X19666230209111854

Koutentakis, M., Surma, S., Rogula, S., Filipiak, K. J., & Gąsecka, A. (2023). The effect of a vegan diet on the cardiovascular system. Journal of Cardiovascular Development and Disease, 10(3), 94. https://doi.org/10.3390/jcdd10030094

Liu, Y., Geng, T., Wan, Z., et al. (2022). Associations of serum folate and vitamin B12 levels with cardiovascular disease mortality among patients with type 2 diabetes. JAMA Network Open, 5(1), e2146124. https://doi.org/10.1001/jamanetworkopen.2021.46124

Zhu, J., Chen, C., Lu, L., Shikany, J. M., D’Alton, M. E., & Kahe, K. (2023). Folate, vitamin B6, and vitamin B12 status in association with metabolic syndrome incidence. JAMA Network Open, 6(1), e2250621. https://doi.org/10.1001/jamanetworkopen.2022.50621

Lopes, M. J. S. (2020). Can vitamin B12 be an adjuvant to COVID-19 treatment? GSC Biological and Pharmaceutical Sciences, 11(3), 1–5.

Cassiano, L. M. G., Cavalcante-Silva, V., Oliveira, M. S., Prado, B. V. O., Cardoso, C. G., Salim, A. C. M., Franco, G. R., D'Almeida, V., Francisco, S. C., & Coimbra, R. S. (2023). Vitamin B12 attenuates leukocyte inflammatory signature in COVID-19 via methyl-dependent changes in epigenetic markings. Frontiers in Immunology, 14, Article 1048790. https://doi.org/10.3389/fimmu.2023.1048790

Zulfiqar, A. A. (2025). Hypervitaminemia B12 in the elderly: A forgotten marker of serious underlying diseases. European Journal of Case Reports in Internal Medicine, 12(8), 005553. https://doi.org/10.12890/2025_005553

Belkhouribchia, J. (2023). Macro-vitamin B12 as cause of falsely elevated cobalamin levels. European Journal of Case Reports in Internal Medicine, 11(1), 004188. https://doi.org/10.12890/2023_004188

Garzone, E. O. C., & Zanella, P. B. (2021). The importance of vitamin B12 for neurological and cognitive function: From pregnancy to childhood. Revista de Atenção à Saúde. https://doi.org/10.13037/ras.vol19n69.7841

Yuan, X., Han, X., Zhou, W., Long, W., Wang, H., Yu, B., & Zhang, B. (2022). Association of folate and vitamin B12 imbalance with adverse pregnancy outcomes among 11,549 pregnant women: An observational cohort study. Frontiers in Nutrition. https://doi.org/10.3389/fnut.2022.947118

Niklewicz, A., Smith, A. D., Smith, A., et al. (2023). The importance of vitamin B12 for individuals choosing plant-based diets. European Journal of Nutrition, 62, 1551–1559. https://doi.org/10.1007/s00394-022-03025-4

Fernandes, S., Oliveira, L., Pereira, A., Costa, M. do C., Raposo, A., Saraiva, A., & Magalhães, B. (2024). Exploring vitamin B12 supplementation in the vegan population: A scoping review of the evidence. Nutrients, 16(10), 1442. https://doi.org/10.3390/nu16101442

Niklewicz, A., Hannibal, L., Warren, M., Kourosh, R., & Ahmadi, A. (2024). A systematic review and meta-analysis of functional vitamin B12 status among adult vegans. Nutrition Bulletin, 49(4), 463–479. https://doi.org/10.1111/nbu.12712

Pawlak, R. (2021). Vitamin B12 status is a risk factor for bone fractures among vegans. Medical Hypotheses, 153, Article 110625. https://doi.org/10.1016/j.mehy.2021.110625

Ghazzawi, H. A., Hussain, M. A., Raziq, K. M., Alsendi, K. K., Alaamer, R. O., Jaradat, M., Alobaidi, S., Trabelsi, K., & Jahrami, H. (2023). Exploring the relationship between micronutrients and athletic performance: A comprehensive scientific systematic review of the literature in sports medicine. Sports, 11(6), 109. https://doi.org/10.3390/sports11060109

Solberg, A., & Reikvam, H. (2023). Iron status and physical performance in athletes. Life, 13(10), 2007. https://doi.org/10.3390/life13102007

Moss, K., Kreutzer, A., Graybeal, A. J., Zhang, Y., Braun-Trocchio, R., Porter, R. R., & Shah, M. (2023). Nutrient adequacy in endurance athletes. International Journal of Environmental Research and Public Health, 20(8), 5469. https://doi.org/10.3390/ijerph20085469

Mouchaileh, N. (2023). Vitamin B12 deficiency in older people: A practical approach to recognition and management. Journal of Pharmacy Practice and Research, 53(6), 350–358. https://doi.org/10.1002/jppr.1897

Mishra, E., & Kumar Thakur, M. (2024). Vitamin B12-folic acid supplementation improves memory by altering mitochondrial dynamics, dendritic arborization, and neurodegeneration in old and amnesic male mice. The Journal of Nutritional Biochemistry, 124, Article 109536. https://doi.org/10.1016/j.jnutbio.2023.109536