Earlier research demonstrated that higher vitamin D levels were associated with improved brainpower or cognitive function in adults, therefore, the researchers decided to establish whether the same also applied to children, and which effect different vitamins, which were sourced mainly from sunlight (vitamin D3) or from plants (vitamin D2), could have.
The findings are based on just over 3,000 children, whose vitamin D3 and D2 levels were measured at an average age of nine years, who took part in the Avon Longitudinal Study of Parents and Children (ALSPAC), which tracks the long term health of a large cohort of children born in the early 1990s.
The researchers assessed the children's academic performance in English, math, and science at 13 and 14 years, and again at 15 and 16 years, using their GCSE exam grades. The findings revealed that higher vitamin D3 levels were more frequent in children from more affluent backgrounds, whilst higher vitamin D2 levels were more frequent in children who came from more disadvantaged backgrounds.
The outcome demonstrated that vitamin D3 levels were not linked to improved academic achievement, and that higher vitamin D2 levels were associated with poorer performance in English in 13 to 14 year olds and achieving less A* to C GCSE grades in those aged between 15 and 16 years.
The researchers state that their results support findings of other vitamin D research in children, yet they do not exclude the possibility that benefits of vitamins on adult brainpower could emerge until later in life, which could be due to vitamins having a greater affect on the ageing brain, or, because the cumulative lifelong effect could be more important.
Another reason could be reverse causality, i.e. people with poorer brainpower spend less time outdoors. Therefore, they have lower vitamin levels in their blood to start with. The researchers highlight that various studies have demonstrated that vitamin D is associated with neurological functions and viability and other various aspects of health.
"These [studies] have resulted in calls for changes to public health guidance regarding extreme protection against UV exposure. However, our results suggest that protection of children from UVB exposure, which has been associated with low levels of vitamin D, but which protects against skin damage and skin cancer, is unlikely to have any detrimental effect on academic achievement."