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About Vitamin B12 & Deficiencies
Vitamin B12 (or B12) is a key nutrient for the workings of the nervous system. Some of its functions include being needed for the formation of the nerve fiber coverings, known as myelin sheaths, for proper nerve function, and even for the synthesis of DNA. If someone does not have enough B12 this can lead to symptoms such as peripheral neuropathy, the feeling of numbness, tingling, muscle weakness, and/or pain, most often in the hands and feet.
It makes sense then that supplementing B12 can help to treat neuropathy that is a result of vitamin B12 deficiency, there is also evolving research in its use for treating other types of neuropathic pain like diabetic and chemotherapy-induced neuropathies (Sun et al. 2016 & Zhou et al. 2013).
Vitamin B12 deficiency can arise a variety of ways, including poor dietary intake (e.g. a risk for those who are vegetarians or vegans), malabsorption syndromes (e.g. celiac disease) and chronic use of certain medications (e.g., metformin or a proton pump inhibitor). Neuropathy associated with B12 deficiency often begins subtly but can become irreversible if not addressed promptly. The research supports vitamin B12 supplementation in the form of intramuscular injections or high-dose oral pills to restore normal vitamin B12 levels in the blood and improve associated neuropathy (O’Leary & Samman, 2010).
Other Neuropathies B12 may Help
Beyond deficiency-related neuropathy, vitamin B12 has shown promise in managing diabetic peripheral neuropathy (DPN). In diabetic individuals, chronic high sugar levels, hyperglycemia ,leads to nerve damage, and several studies have suggested that methylcobalamin, a form of B12, may help regenerate nerves and alleviate these neuropathic symptoms. A randomized controlled trial by Sun et al. (2016) found that methylcobalamin significantly improved nerve conduction speed and reduced pain levels in patients with DPN. This means supplemental vitamin B12 may help with managing diabetic neuropathy, even when blood vitamin B12 levels are within the normal range.
Similarly, research has explored the use of B12 in chemotherapy-induced peripheral neuropathy (CIPN), which is a common side effect of chemotherapy medications like cisplatin and paclitaxel. While the evidence isn’t as strong as it is for DPN, some studies suggest that B12 may offer protective or repairing effects on damaged neurons (Zhou et al., 2013). More high-quality trials are needed to clarify its role in this context.
Overall, vitamin B12 therapy is generally safe and well-tolerated. Injections are often preferred for severe deficiencies or in cases of malabsorption, while oral forms can be effective in more mild cases. Vitamin B12 is relatively safe to take as it has a low toxicity with excess amounts being excreted in the urine as oppose to building up in the body.
Conclusion
In conclusion, vitamin B12 is an essential nutrient with significant implications on neurologic functioning. Its use in treating neuropathy is well-supported in cases of B12 deficiency and shows potential for also managing conditions such as diabetic neuropathy. Although more research is required to define optimal doses and usefulness in neuropathies not stemming from a deficiency, B12 remains a valuable and low-risk therapeutic option in the broader management of neuropathic conditions.
References
- O’Leary, F., & Samman, S. (2010). Vitamin B12 in health and disease. Nutrients, 2(3), 299–316. https://doi.org/10.3390/nu2030299
- Sun, Y., Lai, M. S., Lu, C. J., & Chen, H. M. (2016). Effectiveness of vitamin B12 on diabetic neuropathy: A meta-analysis of randomized controlled trials. Neurology Asia, 21(1), 45–52.
- Zhou, X., He, L., Wu, Y., & Li, N. (2013). Clinical efficacy of methylcobalamin on peripheral neuropathy: A systematic review and meta-analysis of randomized controlled trials. PLoS ONE, 8(5), e71926. https://doi.org/10.1371/journal.pone.0071926