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Evidence-Based Supplement Research

Evidence-Based Supplement Research

Vitamin B9 and Reduced Vitamin B12 Level

Doses used in studies

mg/day: 1–5 (median 3, IQR 2–4) — 2 studies

Time to effect

Median: 2.8 months · IQR 2.8 months–2.8 months · Range 2.8 months–2.8 months — Reported in 1 of 2 studies

2 of 2 papersPopulation:

Folic acid supplementation in children with sickle cell disease: a randomized double-blind noninferiority cross-over trial.
- 2025-04
- RCT · n = 31
- The American journal of clinical nutrition 121(4)
- - Brock A Williams
  - Heather McCartney
  - Joel Singer
  - Angela M Devlin
  - Suzanne Vercauteren
  - Ali Amid
  - John K Wu
  - Crystal D Karakochuk
- PubMed: 39921095
- DOI: 10.1016/j.ajcnut.2025.02.001
11 Insights on
- Reduced Vitamin B12 Level
- High evidence
- Children
There were no significant differences observed in 1-carbon metabolite concentrations (...vitamin B12...).
Effect
Neutral
Effect size
Small
Significant
No
Dose
1 mg/d
Excess Folic Acid and Vitamin B12 Deficiency: Clinical Implications?
- 2024-06
- Review
- Food and nutrition bulletin 45(1_suppl)
- - Joshua W Miller
  - Andre Smith
  - Aron M Troen
  - Joel B Mason
  - Paul F Jacques
  - Jacob Selhub
- PubMed: 38987872
- DOI: 10.1177/03795721241229503
4 Insights on
- Reduced Vitamin B12 Level
- Low evidence
High-dose folic acid supplementation in patients with pernicious anemia or epilepsy cause significant reductions in serum B12.
Effect
Harmful
Effect size
Moderate
Significant
Yes
Dose
High-dose (≥5 mg/d)