Vitamin B12 is necessary for a healthy nervous system and healthy blood cells. The best way to get vitamin B12 is through your diet.

A medication that may interfere with B12 absorption is metformin, a common type 2 diabetes treatment. Having diabetes may make you more prone to B12 deficiency. “B12 is mostly found in animal products. It doesn’t occur naturally in plants. As a result, people who don’t eat meat or dairy products, such as dietary vegans, may be at risk of B12 deficiency.”

References

Kibirige, Davis, and Raymond Mwebaze. “Vitamin B12 deficiency among patients with diabetes mellitus: is routine screening and supplementation justified?” J Diabetes Metab Disord. 2013; 12: 17. Published online 2013 May 7. doi: 10.1186/2251-6581-12-17. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3649932/ (accessed on 8/3/2020).

Chow, Bacon F., PhD, and Howard H. Stone, MD. “The Relationship of Vitamin B12 to Carbohydrate Metabolism and Diabetes Mellitus,” The American Journal of Clinical Nutrition, Volume 5, Issue 4, July-August 1957, Pages 431–439, https://doi.org/10.1093/ajcn/5.4.431. https://academic.oup.com/ajcn/article-abstract/5/4/431/4787047 (accessed on 8/3/2020).

Akinlade, K. S., et. al. “Vitamin B12 Levels in Patients with Type 2 Diabetes Mellitus on Metformin,” Ann Ib Postgrad Med. 2015 Dec; 13(2): 79–83. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4853879/ (accessed on 8/3/2020).

Pietrangelo, Ann; medically reviewed by Stacy Sampson, DO. “What You Need to Know About Diabetes and B-12,” Healthline (updated on June 17, 2020). https://www.healthline.com/health/diabetes/b12-what-you-need-to-know (accessed on 8/3/2020).

Vitamin B12 deficiency linked to heart condition in people with type 2 diabetes
https://www.diabetes.co.uk/news/2016/sep/vitamin-b12-deficiency-linked-to-heart-condition-in-people-with-type-2-diabetes-98548916.html

Vitamin B12 as Protection for the Aging Brain
https://www.nytimes.com/2016/09/06/well/mind/vitamin-b12-as-protection-for-the-aging-brain.html?_r=0