Vitamin B-12 - What I didn't know

摘要

I recently had the opportunity to review the literature on vitamin B_(12). I was astonished at what I didn't know: B12 deficiency is common. Pernicious anemia does not require parenteral B_(12) supplementation. Serum B_(12) and mean corpuscular volume are not reliable indicators of B_(12) status. How was it that I missed this in the course of my 14 years in practice? Simply put, I was unaware much has been discovered in the last decade about this nutrient. The Dietary Reference Intake (DRI) was established for this nutrient in 1998. The DRI recommends supplementation of B_(12) for those over age 50, since up to 30 percent of adults in this age category malabsorb protein-bound B_(12) because of an inability to cleave B_(12) from food from atrophic gastritis and/or hypochlorhydria.