Vitamin D for Kids
Children need vitamin D for growing bones and immune function. Deficiency in childhood causes rickets — impaired mineralisation that manifests as bowed legs, growth failure, and delayed dentition. Sub-clinical insufficiency is much more common than overt rickets and may still affect bone density and infection risk.
Recommended intake by age
| Age group | RDA / AI | Upper limit (UL) |
|---|---|---|
| 0–12 months | 400 IU / 10 µg | 1,000–1,500 IU |
| 1–3 years | 600 IU / 15 µg | 2,500 IU |
| 4–8 years | 600 IU / 15 µg | 3,000 IU |
| 9–18 years | 600 IU / 15 µg | 4,000 IU |
The breastfed infant
Human breast milk contains very little vitamin D (typically < 50 IU/L). The American Academy of Pediatrics and Health Canada both recommend that all breastfed infants receive 400 IU cholecalciferol daily from within the first few days of life, continuing until they are consistently drinking at least 1 L/day of vitamin-D–fortified formula or milk (usually around 12 months).
Signs of deficiency in kids
- Delayed walking or motor milestones
- Bowed legs (genu varum) or knock-knees (genu valgum) beyond typical toddler alignment
- Frontal bossing (prominent forehead)
- Rachitic rosary — palpable beading at costochondral junctions
- Widened wrists and ankles
- Delayed tooth eruption or enamel defects
- Muscle weakness, floppy tone (severe cases)
- Recurrent respiratory infections
How much sun is enough for a child?
Children have thin, efficient skin and generally require less exposure than adults for equivalent vitamin D synthesis. In summer at temperate latitudes, 10–15 minutes of midday sun on face and arms two to three times per week meets typical needs for light-skinned kids. Darker-skinned children may need 2–3× longer. Use our calculator to model your child's exposure needs. Always avoid burning, and consider skin-cancer risk over the lifespan — routine sunscreen use is fine and does not typically cause deficiency.