Apparently the wheels fell off the wagon earlier this month when a prospective cohort study was published online in the Journal of Epidemiology & Community Health in which the authors followed 3,171 children at 10yo with measures of academic performance repeated at 13-14yo & 15-16yo. Vitamin D levels at 10yo were not associated with academic performance but in fact vitamin D was negatively associated with a (not statistically significant) worsening of academic performance. While the authors did not conjure this possibility, I envision that high vitamin D levels might be due to playing outside rather than studying inside which would have led to higher academic performance.
randomized placebo-controlled trial was also published earlier this month in the Lancet concluding that vitamin D supplementation did not prevent pneumonia in vitamin D deficient Afghan infants. The authors had randomized 1,524 children 1-11mo to 100,000 units of vitamin D3 every quarter for 18 months compared to 1,522 similar children who received placebo in a similar fashion. Unfortunately, no difference was seen in incidence or severity of childhood pneumonia, hospital admission rates, and all-cause mortality.
So while we debate the potentially pleomorphic benefits of vitamin D, let's not expect world peace, much less improvement in academic performance nor decrease in childhood pneumonia.