Big effect

Vitamin B12 cut deficiency risk by 56 per 1,000 children in a meta-analysis — but had zero effect on growth, cognition, or anemia in those same kids.

This is high-certainty evidence that B12 supplementation corrects a lab deficiency, but it does not seem to translate into the real-world benefits many parents might hope for — and since the finding comes from a single meta-analysis, it needs to be replicated before assuming it holds across all settings.

A meta-analysis of 3 trials involving 642 children found that vitamin B12 supplementation reduced the rate of B12 deficiency from 7.6% to 1.8% — a large and statistically robust effect. However, the same studies measured height, cognitive function, motor skill development, and anemia, and found no improvement in any of them, meaning the benefit was purely a lab-measured rise in blood levels without downstream gains.

Where this fits in the evidence

This is among the first studies we've indexed on Vitamin B12 for Reduced Vitamin B12 Deficiency — treat it as an early signal until more research accumulates.

The study

Vitamin B12 supplementation for growth, development, and cognition in children.

Meta-Analysis
n = 4,083
2026-06-02
The Cochrane database of systematic reviews

More on Vitamin B12 More on Reduced Vitamin B12 Deficiency

This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.