Significant increase of serum B12 levels with high-dose oral vitamin B12 supplementation with or without intrinsic factor after Roux-en-Y gastric bypass: A randomized controlled trial

Abstract

VitB12 deficiency is frequently encountered after RYGB. Low-dose oral supplements are not sufficient to avoid this deficiency, often implying treatment with intramuscular injections. As IF plays an important role in vitB12 absorption, there might be an additional effect in adding IF to oral vitB12 supplements. This randomized, monocentric, double-blind, placebo-controlled trial evaluates the short-term effect of high-dose (1000 μg) oral vitB12 supplementation on serum vitB12 levels after RYGB. 225 patients were randomized into three treatment arms: vitB12, vitB12 in combination with intrinsic factor (vitB12IF) or placebo. Serum vitB12 levels 6 months postoperatively were significantly higher in patients receiving vitB12 compared to placebo (p < 0.001). A mean decrease of 197.6 (SD ± 37) ng/L vitB12 and an augmentation of 154 (SD ± 97.8) ng/L and 202.3 (SD ± 113) ng/L were respectively observed in the placebo, vitB12 and vitB12IF groups. Our study shows no significant benefit in adding IF compared to high dose oral vitB12 without IF (p = 0.711). High-dose oral vitB12 supplements significantly increase serum vitB12 levels after RYGB, confirming the efficacy of such treatment, without a significant benefit of adding IF to the vitB12 supplement. • RCT comparing high-dose oral vitB12 ± Intrinsic factor supplementation after RYGB with placebo. • Serum vitB12 declines without supplementation after Roux-en-Y gastric bypass (RYGB). • High-dose oral vitB12 supplementation increases serum vitB12 levels after RYGB. • Addition of intrinsic factor has no significant benefit on postoperative vitB12 level.