B is for Better: Vitamin B12 and Diabetic Foot

Prescribers often use vitamin B12 (cyanocobalamin) to treat megaloblastic anemia, a condition in which supply of oxygen carried in red blood cells cannot meet the demand of the body organs. Low levels of vitamin B12 can lead to anemia or nerve damage.¹ A recent mini review published in the International Journal of Lower Extremity Wounds found that vitamin B12 supplements have a positive association with improvements in diabetic neuropathy and quality of life.

Vitamin B12, which is essential for cellular metabolism and DNA synthesis and methylation, is found in animal-based foods, dried lavers, and mushrooms. B12 deficiency is often due to a lack of consumption of vitamin B12 rich foods or malabsorption.

It is commonly seen in older adults, but it can affect patients of all ages. Deficiency can lead to anemia, neuropathy, dementia, and gastrointestinal disorders.

Diabetic neuropathy is bilateral sensory loss that may worsen and result in motor impairment. Patients with diabetic neuropathy can exhibit loss of thermosensation and nociception, which can lead to the development of diabetic foot ulcers.

The investigators analyzed 5 observational studies from 1998 to September 2022. A search was performed using key words of “diabetic foot,” “vitamin B12,” and “diabetes.”

These investigators found that vitamin B12 may be of benefit to patients with diabetic neuropathy and diabetic foot ulcers. Two of the studies found B12 supplementation to be associated with improvement in pain scores and electrochemical skin conduction in the feet.

Another study found improved sweat gland function in the feet leading to hydrated skin and possibly decreasing the risk of ulcer formation, but further studies are needed to explore this relationship.

Vitamin B12 is available as intramuscular injections and oral formulations. Parenteral administration is recommended for patients with severe low serum levels of vitamin B12 or malabsorption. Oral intake of vitamin B12 through diet or supplements are adequate for less severe cases.

Vitamin B12 deficiency is commonly seen in patients with diabetic foot ulcers due to impaired absorption resulting from treatment with metformin and/or bariatric surgery, both of which have been associated with low vitamin B12 levels. It is reasonable to sustain a vitamin B12 level within normal limits in patients with diabetic neuropathy and/or diabetic foot infection.

Interest in the relationship between vitamins and diabetic foot ulcers continues to grow, but more studies are needed to provide recommendations on utilization in clinical practice.

About the Author

Anne Lin, PharmD, BCPS is an emergency medicine clinical pharmacist at St. Vincent’s Medical Center in Bridgeport, CT.

References

1. Cyanocobalamin injection. Medlineplus Drug Information. Accessed January 5, 2023. https://medlineplus.gov/druginfo/meds/a605007.html
2. Karakousis ND, Pyrgioti EE, Georgakopoulos PN, Papanas N. Vitamin B12 and Diabetic Foot: Α Mini-Review [published online ahead of print, 2022 Nov 29]. Int J Low Extrem Wounds. 2022;15347346221143018. doi:10.1177/15347346221143018