Oral Vitamin B12 Supplementation After Roux-en-Y Gastric Bypass: a Systematic Review

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#administration-oral #adult #chemoprevention #dietary-supplements #dose-response-relationship-drug

Oral Vitamin B12 Supplementation After Roux-en-Y Gastric Bypass: a Systematic Review

Mahawar et al., 2018 | Obes Surg | Systematic Review

Citation

Mahawar Kamal K, Reid Alastair, ... Small Peter K. Oral Vitamin B12 Supplementation After Roux-en-Y Gastric Bypass: a Systematic Review. Obes Surg. 2018-Jul;28(7):1916-1923. doi:10.1007/s11695-017-3102-y

Abstract

BACKGROUND: Many respectable guidelines recommend lifelong vitamin B12 injections for Roux-en-Y gastric bypass (RYGB) patients in the absence of lack of consensus on the efficacy of oral route of prophylaxis and the appropriate doses needed for this purpose. The purpose of this review was to examine the published English language scientific literature in accordance with PRISMA principles to find out if orally given vitamin B12 is adequate for prophylactic purposes in RYGB patients and the appropriate dosages needed for this purpose if it is. METHODS: We examined the PubMed database for all English language articles examining various doses of oral vitamin B12 supplementation after proximal RYGB in adult patients. The search revealed 19 such articles. RESULTS: The data suggest that oral vitamin B12 supplementation doses of ≤ 15 μg daily are insufficient to prevent deficiency in RYGB patients. Higher supplementation doses show better results and it appears that a dose of 600.0 μg vitamin B12 daily is superior to 350.0 μg daily suggesting an incremental dose-response curve. It further appears that supplementation doses of 1000.0 μg vitamin B12 daily lead to an increase in B12 levels and are sufficient for the prevention of its deficiency in most RYGB patients. CONCLUSION: The review finds that oral supplementation doses of ≤ 15 μg vitamin B12 daily are inadequate for prophylaxis of vitamin B12 deficiency in adult RYGB patients but doses of 1000 μg vitamin B12 daily might be adequate. Future studies need to examine this and even higher oral doses for vitamin B12 supplementation for patients undergoing RYGB.

Key Findings

The data suggest that oral vitamin B12 supplementation doses of ≤ 15 μg daily are insufficient to prevent deficiency in RYGB patients. Higher supplementation doses show better results and it appears that a dose of 600.0 μg vitamin B12 daily is superior to 350.0 μg daily suggesting an incremental dose-response curve. It further appears that supplementation doses of 1000.0 μg vitamin B12 daily lead to an increase in B12 levels and are sufficient for the prevention of its deficiency in most RYGB pa

Outcomes Measured

  • Requires manual extraction

Population

Field Value
Population adult patients
Sample Size See abstract
Age Range See abstract
Condition deficiency

MeSH Terms

  • Administration, Oral
  • Adult
  • Chemoprevention
  • Dietary Supplements
  • Dose-Response Relationship, Drug
  • Drug Administration Schedule
  • Female
  • Gastric Bypass
  • Humans
  • Male
  • Obesity, Morbid
  • Postoperative Complications
  • Vitamin B 12
  • Vitamin B 12 Deficiency

Evidence Classification

  • Level: Systematic Review
  • Publication Types: Journal Article, Systematic Review
  • Vertical: vitamin-b12

Provenance

Source extracted via PubMed E-utilities API on 2026-04-09