Editorial: A Special Tree in the Forest: From Oak to Acorn to Oak.

In this issue of the Journal, Sucksdorff et al. present additional evidence of maternal health and nutrition during pregnancy affecting offspring mental health. In the Finnish National Registry, the authors identified 1,067 cases of attention-deficit/hyperactivity disorder (ADHD) and 1,067 matched controls. They found a highly significant negative association between maternal 25-hydroxyvitamin D levels in the first half of pregnancy and later diagnoses of ADHD in offspring. The lower the level of vitamin D in mothers, the greater the risk of ADHD in offspring, even after adjusting for maternal age and socioeconomic status (p = .002). This finding confirms what had previously been reported less conclusively and raises several points worthy of comment. Among these are the special characteristics of vitamin D within an array of micronutrients necessary for brain health, development, and function; the possibility that vitamin D levels are markers for general micronutrient insufficiency; the importance of nutrition for maternal mental health in view of the psychological impact of maternal mental state on the child; and the need for further research on brain nutrition, including randomized clinical trials (RCTs).