Daily vitamin B-12 supplementation for 1 year in infants at risk of vitamin B-12 deficiency did not reduce the burden of common infections, with an incidence rate ratio for health clinic visits of 0.99 (95% CI: 0.85, 1.14).
Vitamin B-12 supplementation had no statistically significant effect on health clinic visit incidence compared to placebo.
No statistically significant effect of vitamin B-12 supplementation was found on any of the 20 clinical infection outcomes measured.
Trial retention and compliance were high, with only 26 children lost to follow-up and nearly 95% of scheduled doses taken.
The study also reassessed the effect of supplementation on biomarker concentrations stratified by baseline vitamin B-12 status.
The study population was characterized by risk of vitamin B-12 deficiency and prevalent childhood infections, making it a relevant context for testing the supplementation hypothesis.
This research studied whether giving young infants in Nepal a daily vitamin B-12 supplement for one year would reduce how often they got sick. The study enrolled 600 babies aged 6 to 11 months who were at risk of having low vitamin B-12 levels — a common nutritional problem in this region. Half received a small daily dose of vitamin B-12 (2 micrograms) and half received a placebo (inactive pill), and neither the families nor the researchers knew which each child was getting. Researchers tracked clinic visits and signs of 20 different common illnesses over the year. The results showed no meaningful difference between the two groups. Children in the vitamin B-12 group made 1,474 health clinic visits, while those in the placebo group made 1,498 — essentially the same rate. None of the 20 individual illness outcomes showed a statistically significant difference between groups. The study had very good participation, with nearly 95% of doses taken and very few children dropping out, meaning the results are reliable. This research suggests that giving vitamin B-12 supplements to infants at risk of deficiency does not reduce their likelihood of getting common childhood infections, even in a setting where such deficiency and infections are widespread. This is notable because vitamin B-12 plays a role in immune function, so there was a reasonable scientific basis to expect a benefit. The findings add to previously published results from the same trial showing effects (or lack thereof) on growth, brain development, and blood health markers.
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Upload Your LabsStrand T, Chandyo R, McCann A, Ranjitkar S, Ulak M, Kvestad I, et al.. (2026). The Effect of Daily Vitamin B-12 Supplementation on the Incidence of Common Childhood Infections in Nepal: Secondary Outcomes from a Double-Blind Randomized Controlled Trial.. The Journal of nutrition. https://doi.org/10.1016/j.tjnut.2026.101534