Vitamin D in Toddlers

Editor(s): Mairead Kiely.

Key Messages

  • Young children are at risk of low vita­min D intakes and status
  • National surveys, prospective cohorts, and dietary intervention studies have shown that fortification of foods con­sumed by toddlers is a safe and effec­tive approach to increasing their vita­min D intakes and status
  • Dose-response trials in 1 to 3-year-olds are still needed to estimate the actual vitamin D requirement among toddlers


Young children and toddlers (1–3 years) are at risk of nutrient deficiencies due to their limited appetite relative to their high requirements for growth and de­velopment. Vitamin D has been identi­fied as a risk nutrient for toddlers in many countries. Vitamin D is a fat-sol­uble vitamin that is obtained from a combination of skin synthesis during sunshine exposure and from the diet. As it has a key role in the regulation of calcium and phosphorus metabolism, vitamin D is critical for healthy bone growth and development in childhood. Prevention of very low vitamin D sta­tus is also important for robust im­mune function.

Vitamin D in the Diets of Young Children

Due to the extended winter period, people resident at high latitudes need to obtain sufficient vitamin D from the diet for prevention of vitamin D deficiency. Foods containing substan­tial amounts of naturally occurring vita­min D are limited and not consumed on a regular basis by young children. Small but important amounts of vita­min D3 are found in commonly con­sumed staple foods, such as meat, dairy, and eggs. Vitamin D2 (ergocalciferol) can be obtained from irradiated mushrooms. Depending on regional legislation, some foods are fortified with vitamin D, including milk, infant formula, yogurt, spread, cheese, juice, bread, and breakfast cereals. In addi­tion, vitamin D is available as a dietary supplement, either as vitamin D2 or vitamin D3.

Recommended Intakes of Vitamin D in Toddlers

Current recommendations for indi­vidual intakes of vitamin D in Europe and North America vary between countries, from 10 to 20 µg/day (400 to 800 IU), shown in Table 1. Based on adult recommendations, these are the intakes of vitamin D that will ach­ieve circulating 25-hydroxyvitamin D (25(OH)D) concentrations (the bio-marker of vitamin D status) of 25–50 nmol/L, for the prevention of adverse bone health outcomes.


Intakes of Vitamin D among Toddlers Relative to Recommendations

Vitamin D intakes among young chil­dren are generally between 2 and 9 µg/ day, including countries with manda­tory or voluntary vitamin D fortification [1]. While nutritional supplements can be important contributors to vitamin D intake, current rates of supplement use among toddlers are often low [2, 3]. Key food sources of vitamin D in tod­dlers are vitamin D-fortified milks, formula, breakfast cereals and yogurts, meat, and eggs [4]. Even in countries where voluntary fortification with vitamin D is widespread, almost all chil­dren have intakes of vitamin D below 10 µg/day [3].

Is There Evidence for Low Vitamin D Status among Toddlers?

Evidence for extensive low vitamin D status is mixed, and it seems that average 25(OH)D concentrations among children decrease with increasing age, possibly due to reducing milk intake. In the UK National Diet and Nutrition Survey among 1.5- to 3-year-olds, the prevalence of year-round plasma 25(OH)D concentrations <25 nmol/L was 8% [5]. In a study of 741 toddlers from the prospective Cork BASELINE Birth Cohort, the year-round prevalence of serum 25(OH)D <25 nmol/L was 1.6%, and 4.6% were <30 nmol/L, which increased to 8.6% during the winter months (November to April) [1]. In this cohort, over a quarter of the children had a 25(OH)D concentration <50 nmol, which reached almost half the study cohort in winter. Apart from season, consumption of at least 5 µg/day of vitamin D and consumption of fortified infant formula were the main determinants of circulating 25(OH)D. In Montreal in 2013, El Hayek et al. [6] reported that despite 95% of 508 preschoolers having vitamin D intakes <10 µg/day, plasma 25(OH)D was >50 nmol/L in 88% of them, which was likely due to the dual effect of fortified milk provision and skin synthesis.

Ways to Improve Intakes/Status of Vitamin D

The current dietary supply of vitamin D is not sufficient to close the large gap between dietary intakes and recommendations for vitamin D in tod­dlers, and many children are at risk of low vitamin D status during this growing period. While vitamin D-con­taining supplements can increase vita­min D intakes and status, this is only true for supplement users. From a pub­lic health policy perspective, food forti­fication with vitamin D is likely to be the best option for increasing vitamin D in­takes and status across the population distribution. Milk and milk products are widely consumed among toddlers, and there is abundant evidence from large observational studies [1–4, 6, 7], trials [8], and a recent systematic review of trials [9] that consumption of vitamin D-fortified milk or formula increases vitamin D intake and status, without the risk of excessive intakes or adverse effects.

In summary, dose-response ran­domized controlled trials in children aged 1–3 years are still required to estimate the vitamin D require­ment of young children and to make evidence-based recommendations. From a public health nutrition perspec­tive, fortified foods provide a feasible solution to ensuring an adequate di­etary supply of vitamin D in toddlers.


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