This abstract was awarded the student prize.
The primary sources of vitamin D are epidermal vitamin D synthesised via UVB exposure and dietary sources from oily fish, meat and fortified foods and supplements(1). In Northern latitudes (>37°), between September and March, sun exposure is insufficient to synthesise enough vitamin D, and dietary sources including the use of supplements, are important to meet requirements(1). The UK government currently recommends a 10 μg/day vitamin D supplement for children to maintain vitamin D status from October to March(1). The reference nutrient intake (RNI) for vitamin D is 10 μg/day; however, current mean(SD) intake is 4.2(3.1) μg/day(2) and only 10% of children take a vitamin D containing supplement(3).
This study investigates dietary sources of vitamin D in a convenient sample of school children in Northern Ireland. Secondary analysis investigated the relationship between age and vitamin D intake. Forty-four children were recruited between November 2019 and March 2020 as part of a larger study. Height and weight were measured, and daily vitamin D intake and consumption of vitamin D rich foods were assessed via a six-month retrospective food frequency questionnaire (FFQ)(Reference Weir, Carson and Mulhern4).
The study cohort had a mean age of 8.1±2.1 years and 64% (28) were female. Mean(SD) height was 1.3(0.1) m, mean(SD) weight was 32.2(12.2) kg and the children's mean(SD) body mass index (BMI) was 17.6(3.2) kg/m2. Mean(SD) dietary vitamin D intake, derived from the FFQ and including vitamin D supplement contribution, was 6.4(5.6) μg/day. Vitamin D intakes of children taking a vitamin D supplement (8, 18%; 16.5±4.3) were significantly higher than those not taking a supplement (36, 82%; 4.2 ± 2.5), p < 0.001; 95% CI). There was no difference in vitamin D intake between boys and girls. The top five contributing food groups were as follows: breakfast cereals (1.3(1.0) μg/day), fish (1.0(1.2) μg/day), spreads (0.6(0.6) μg/day), meat (0.5(0.6) μg/day) and eggs (0.5(0.5) μg/day). Age (years) was negatively correlated with vitamin D intake (μg/day) (rs=−0.36, p = 0.02) and supplement intake (μg/day) (rs=−0.32, p = 0.033).
Mean dietary vitamin D intake in this cohort was below the current recommendation, whereas those children who were taking a supplement met the daily recommendation. The food groups that contributed the most towards total vitamin D intake were vitamin D-containing supplements, fortified breakfast cereals, fish, meat, and eggs. Future public health messages need to focus on promoting vitamin D rich foods, including fortified foods, in addition to highlighting the importance of supplementation, particularly during the winter months. Mandatory vitamin D food fortification may need considered.
