Purpose: While reports of inadequate vitamin D intakes among young children are widespread, data on the prevalence of vitamin D deficiency are inconsistent. We aimed to quantify vitamin D intake and serum 25-hydroxyvitamin D [25(OH)D] concentrations in children aged 2 years in the prospective Cork BASELINE Birth Cohort Study. Methods: Serum 25(OH)D was analysed using UPLC-MS/MS in 741 children living in Cork, Ireland (51°N). Two-day weighed food diaries were collected in 467 children, and 294 provided both a blood sample and a food diary. Results: Mean (SD) 25(OH)D concentrations were 63.4 (20.4) nmol/L [winter: 54.5 (19.9), summer: 71.2 (17.5)]. The prevalence of vitamin D deficiency (OpenSPiltSPi30 nmol/L) was 4.6, and 26.7% were OpenSPiltSPi50 nmol/L [45.2% during winter (November–April) and 10.4% in summer (May–October)]. With a mean (SD) vitamin D intake of 3.5 (3.1) µg/day, 96% had intakes below 10 µg/day, the current IOM estimated average requirement and the SACN safe intake value for this age group. After adjustment for season, vitamin D intake (µg/day) was associated with higher 25(OH)D concentrations [adjusted estimate (95% CI) 2.5 (1.9, 3.1) nmol/L]. Children who did not consume vitamin D-fortified foods or supplements had very low vitamin D intakes (1.2 (0.9) µg/day), and during winter, 12 and 77% were OpenSPiltSPi30 and OpenSPiltSPi50 nmol/L, respectively, compared with 6 and 44% of fortified food consumers. Conclusion: There was a high prevalence of low vitamin D status during winter, especially among children who did not consume fortified foods or nutritional supplements. Our data indicate the need for dietary strategies to increase vitamin D intakes in this age group. This report provides further evidence that DRVs for vitamin D should be based on experimental data in specific population groups and indicates the need for dose–response RCTs in young children.
ní Chaoimh, C., McCarthy, E. K., Hourihane, J. O. B., Kenny, L. C., Irvine, A. D., Murray, D. M., & Kiely, M. E. (2018). Low vitamin D deficiency in Irish toddlers despite northerly latitude and a high prevalence of inadequate intakes. European Journal of Nutrition, 57(2), 783–794. https://doi.org/10.1007/s00394-016-1368-9