Vitamin B12 (cobalamin) is a water-soluble vitamin that is present in certain food and available as a dietary supplement. Like vitamin D, deficiency of this vitamin is common, especially in older people, in whom absorption by the gut may be decreased. Vitamin B12 is essential for the development and maintenance of healthy red blood cells and nerve tissue, including the brain. Vitamin B12 is involved in a myriad of important chemical reactions in the body, including those affecting DNA and RNA.
Vitamin B12 is deficient in 20% of those over 60 years of age. The incidence is higher in people with intestinal disorders, including inflammatory bowel disease and Crohn’s disease. Inadequate levels of Vitamin B12 is associated with enlarged and deficient red blood cells, or “megaloblastic anemia,” as well as inflammation of the tongue (“glossitis”), fatigue, heart palpatations, dementia, weight loss, and infertility. Vitamin B12 deficiency is often treated with injections, since this route bypasses problems with intestinal absorption.
Vegans who consume no animal products and non-meat eaters are at risk of developing vitamin B12 deficiency since natural food sources rich in this vitamin are limited to animal foods.
Consuming fortified nutritional yeast (a favorite of mine) reduces this risk. Drugs such as gastric acid inhibitors, including Prilosec, Prevacid, Tagamet, and Zantac, may interfere with vitamin’s absorption.
Of note, metformin may also reduce the absorption of vitamin B12 . Metformin an anti-hyperglycemic drug used in type 2 diabetes. Metformin also has been associated with anti-aging effects, and it has gained great popularity for this reason in the past several years.
Diseases in which low levels of this vitamin may be contributary include the 4 horsemen of aging: cardiovascular, metabolic, neurologic, and immunologic disorders, including cancer.
The evidence for these associations is not solid., however. Similarly, though vitamin B12 is touted as an energy enhancer that improves athletic performance and endurance, studies have refuted this claim except in the case of deficiency disease.
Being water-soluble, it has a low potential for toxicity. Even at large doses it is considered to be safe, since excess quantities are eliminated in the urine.
A simple blood test is available to confirm the blood concentration of vitamin B12. I recommend this test, especially to people over 60 years of age and those taking the drugs listed above. If leves are low, e.g. < 450 pg/mL, supplementation is indicated. Whether injections are superior to oral or sublingual routes is a matter of debate. The route of administration and dosing can be discussed with a physician or nutritionist.
Fortunately, levels can be followed serially to ensure the optimal concentration is achieved.
Note: Although I am a physician, the content in this article is not meant to diagnose, treat, cure or prevent illness or disease in the reader – it is for educational purposes only.
References
- Allen LH. Vitamin B-12. Adv Nutr 2012;3:54-5.
- Langan RC, Goodbred AJ. Vitamin B12 deficiency: Recognition and management. Am Fam Physician 2017;96:384-9.
- Sharabi A, Cohen E, Sulkes J, Garty M. Replacement therapy for vitamin B12 deficiency: Comparison between the sublingual and oral route. Br J Clin Pharmacol 2003;56:635-8.
Leave a Reply
You must be logged in to post a comment.