Vitamin D and Cognitive Function in Adolescents
Recent research points to the potential benefits of vitamin D supplementation on executive function in adolescents.
Adolescence is a critical period for brain development and reorganization of many regulatory systems, like the body’s hormonal system. These kinds of developmental changes contribute to a teen’s working memory, mental flexibility, and self-control. It is imperative to protect the brain during these critical years of growth.
Recent research points to the potential benefits of vitamin D supplementation on executive function in adolescents. Vitamin D is usually acquired in the diet and through sun exposure. But for adolescents living in high-latitude countries, like Norway, this daily nutrient requirement is often not met.
Researchers from the University of Bergen and their colleagues from nearby universities and government institutes conducted an experiment in the winter of 2016. They tested several hypotheses on the relationship between adolescent’s vitamin D levels and executive function. The link between vitamin D levels and self-reported mental health was also researched. This experiment tested the relationship between vitamin D supplementation and quality of performance on two executive function tests. To account for self-perceived mental health, a survey was given to all participants.
The study subjects were 52 Norwegian adolescents who participated in the experiment after school. The study was a randomized double-blind placebo control trial. All subjects were given a pill to take every day for the duration of the study, but only half were given pills containing a vitamin D supplement. A blood draw and three online pre-tests helped researchers establish a baseline for vitamin D levels and executive function performance.
The first two tests were called the Tower of London, and the Tower of Hanoi, respectively. The purpose of these tests was to observe the teenager’s ability to plan and “look ahead” by predicting how many steps would be required to solve a complex problem. The final pre-test was a self-report of the adolescent’s mental health. There is a well-established link between mental health and vitamin D. So the researchers wanted to support their experiment with this standard.
Performance on each of the two executive function test and self-report of mental health were evaluated for each subject at the beginning of the study and 4-5 months later. With half of the participants supplementing with vitamin D pearls on a daily basis, the experimenters had three predictions to test:
- Vitamin D supplementation would be beneficial on both executive function tests
- Vitamin D supplementation during winter would improve self-perceived mental health
- Vitamin D supplementation would increase overall levels of vitamin D in adolescents
The results supported researchers’ initial predictions —with the exception of self-perceived mental health. Contrary to expectations, no change in self-perceived mental health was reported by any of the participants. An overall improvement of score between pre- and post-test was demonstrated by all participants in the Tower of London test, regardless of vitamin D intervention.
It was later concluded by the researchers that there was a considerable difference in difficulty between the Tower of London and Tower of Hanoi tests. The variations between scores on the Tower of Hanoi test were far greater. The intervention group exceeded their pre-test scores on the most difficult of the Tower of Hanoi tasks, while no remarkable improvement was noted in the control group.
What can be gathered from the results of this study? It is clear that there is a possible link between vitamin D supplementation and executive function. More studies should be conducted to determine the strength of this relationship. Although this study was conducted in Norway, the results can be extrapolated and applied to adolescents all over the world.
For adolescents who are looking for a dietary solution to support healthy executive function, this study indicates that meeting daily recommendations of vitamin D can help reach that goal. Supplementation of this essential vitamin may be the most practical way to increase the daily intake of vitamin D for teens – particularly those living at high latitudes.
Grung, Bjørn, Asle M. Sandvik, Kay Hjelle, Lisbeth Dahl, Livar Frøyland, Irene Nygård, and Anita L. Hansen. “Linking vitamin D status, executive functioning and self-perceived mental health in adolescents through multivariate analysis: A randomized double-blind placebo control trial.” Scandinavian Journal of Psychology 58.2 (2017): 123-30. Web.