Effect of vitamin and mineral supplementation on verbal and non-verbal reasoning of schoolchildren.

In a randomised controlled trial the effect of vitamin and mineral supplementation for seven months on performance in tests of reasoning was studied in 86 schoolchildren aged 11-13. A small, non-significant difference between the control and supplementation groups was found in a non-verbal test. The net difference in change in scores between the active and placebo groups was 2.4 units (95% CI-1.5 to 6.3). This direction of effect was not consistently seen with three other tests of non-verbal reasoning. Vitamin and mineral supplementation does not improve the performance of schoolchildren in tests of reasoning.