Research synthesisLow evidenceMixed effect size3 studies · 3 beneficial · 0 neutral · 0 harmful
Across all 3 studies in the database, Lactobacillus plantarum 299v supplementation consistently showed beneficial effects on iron status, with 2 of 3 studies reporting statistically significant improvements. Effect sizes ranged from small to large, with a moderate median effect; the largest and highest-quality trial (n=295, RCT) found significantly higher serum iron levels in the probiotic group. Evidence is concentrated in pregnant women and individuals with iron deficiency anemia, with a median study duration of 90 days (reported in 1 study).
- Effective dose range: 10^10 CFU/day
- Studied populations: pregnant women, individuals with iron deficiency anemia
Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Most studies were conducted in pregnant women or clinical IDA populations; generalizability to other groups is uncertain. Doses varied across trials, with only one specifying a dose (10^10 CFU/day), making a consistent effective dose range difficult to define.
Generated May 18, 2026