For Canadian parents, vitamin D can be a surprisingly complicated nutrient. Children need it for healthy bones, but getting enough can be challenging in a country where sunlight isn’t a reliable year-round source. Add picky eating and busy schedules – you may be wondering: How much vitamin D do Canadian kids need?
Understanding where vitamin D comes from, which children may be at greater risk of deficiency and when supplementation may be appropriate can help parents and practitioners make informed decisions.
Vitamin D is an essential micronutrient everyone needs for optimal health. When the body doesn’t regularly get enough, it can interfere with health without showing clinical signs. It plays a role in the health of bones, the immune system, and overall wellness.
Vitamin D, along with calcium and magnesium, plays an important role in healthy bone development. It helps support the processes involved in bone mineralization, the process by which bones combine minerals to build strong structures.
Strong bones start in childhood. A review of 13 clinical studies in healthy children and adolescents found a connection between vitamin D levels and bone mineral density. While factors such as age and nutrition also affect bone health, the findings suggest that getting enough vitamin D may help support growing bones. More research is needed to understand how vitamin D levels influence bone health over the long term.
For decades, vitamin D has been used to prevent and treat nutritional rickets in children.
Vitamin D also has a role in immune function, with vitamin D receptors found on cells involved in both innate and adaptive immunity.
Evidence suggests that vitamin D supplementation may help reduce the rates of infections in paediatric populations.
Research also suggests there may be a beneficial role of vitamin D supplementation in preventing autoimmune disorders, with data potentially linking vitamin D deficiency to increased rates of childhood asthma and other allergic conditions.
More research is needed before recommendations can be made in the possible use of vitamin D in these conditions, but evidence appears to show vitamin D plays a role in children’s immune health.
Sunlight is the most common way the body is able to increase its vitamin D levels. When exposed to sunlight, skin can create vitamin D.
But Canada’s high latitude prevents year-round vitamin D synthesis through sun exposure. As such, milk is fortified in Canada with vitamin D. For kids who don’t eat dairy, look for dairy alternatives that are supplemented with vitamin D.
Food sources of vitamin D include egg yolks, mushrooms and fatty fish, such as salmon. This could be a problem if you have a picky eater to contend with – mushrooms and fish aren’t typically on kids’ favourite food lists. These kids may be at greater risk of deficiency.
For some kids, vitamin D supplementation may be needed.
Canadian children may not be getting enough vitamin D. Data from the Canadian Health Measures Survey found that vitamin D status declined among children ages 6 to 18 between 2007–2009 and 2012–2013. During that time, the percentage of children who had sufficient vitamin D fell from about 79% to 68%. The number of Canadian children with insufficient vitamin D levels rose to 25%, and those who were deficient increased from 4.3% to 6.5%.
What might be contributing to the gap? The study found that age, household income, weight status, ethnicity and season were associated with vitamin D status. Older children, children from lower-income households and children who were overweight or obese were less likely to have sufficient vitamin D levels.
Another important finding is that Vitamin D levels also tended to be higher in the summer and fall than in the winter. Thus, vitamin D is an important nutrient to consider during winter months.
Diet may be another piece of the puzzle. Milk was the main dietary source of vitamin D among the children studied, but both milk and fish consumption declined between the two survey periods. Eggs and red meat consumption did not change significantly. Because Canada’s northern latitude limits vitamin D production from sunlight for much of the year, relying on sun exposure alone may not provide enough vitamin D.
For parents, the takeaway is simple: pay attention to vitamin D sources throughout the year. Include vitamin-D-rich and fortified foods as part of your child’s regular diet, and talk with a healthcare professional about whether a vitamin D supplement is appropriate for your child. This may be particularly important during the Canadian winter or when a child has factors that may increase their risk of low vitamin D.
For some children, supplementation is an important way to help meet vitamin D needs.
Risk factors identified by the Canadian Paediatric Society for kids at greater risk of vitamin D insufficiency include:
For practitioners, this reinforces the value of looking at the whole child and their circumstances, rather than relying on age alone when discussing vitamin D for kids.
The amount of vitamin D a child needs depends on age, feeding method and individual risk.
For healthy children, many paediatric guidelines recommend approximately 400 IU daily for infants and 600 IU daily for children aged 1 to 18 years to support bone health.
The Canadian Paediatric Society recommends:
When researchers reviewed 7 clinical studies (a total of 5,748 children younger than five years) they found that higher-dose vitamin D (1000 IU)supplementation did not significantly reduce upper respiratory tract infections compared to 400IU. In other words, vitamin D is important for normal immune function, but more vitamin D is not automatically better.
There are two main forms of vitamin D supplements: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).
Research suggests that vitamin D3 is more effective than vitamin D2 at raising the blood levels of vitamin D.
Got a picky kid? Luckily, there are options in Canada for all kinds of kids that need a vitamin D supplement, including liquid drops, chewables, and gummies.
Vitamin D is a small nutrient with a big job during childhood. It supports the mineralization of growing bones and participates in immune function. But Canada’s northern latitude can make obtaining enough from sunlight challenging. Add in picky eaters and busy schedules, and some kids aren’t getting enough.
Focusing on vitamin D-rich foods and understanding when supplementation is recommended can help support the individual vitamin D needs of kids. For practitioners, when working with children and families navigating these surprisingly complicated nutrients, it’s important to consider eating patterns, food access, geography, sun exposure, growth and the child’s broader nutritional picture.
Having a deeper understanding of children’s nutrition can make a difference.
If you’re interested in learning more about the nutritional needs of children and how nutrition fits into a holistic approach to health, learn more about programs available at the Canadian School of Natural Nutrition, including distance education options.
Learning more about kids’ nutrition today!
Fleet, JC. J Ster Biochem Mol Bio 2025 May; 249:106718.
Karimian P, et al. J Family Med Prim Care. 2022 Mar;11(3):870-878
