Vitamin D Dosing for a Healthy 5-Year-Old Child
For a healthy 5-year-old child without deficiency, prescribe 600 IU of vitamin D3 (cholecalciferol) daily as standard maintenance supplementation. 1, 2
Standard Maintenance Dosing
Children aged 1-18 years require 600 IU/day of vitamin D from all sources (diet plus supplements) according to the American Academy of Pediatrics, the European Society for Pediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN), and the Institute of Medicine. 1, 2
This daily dose is designed to maintain serum 25(OH)D levels above 20 ng/mL (50 nmol/L), which is the target for bone health and prevention of deficiency. 1, 2
Cholecalciferol (vitamin D3) is preferred over ergocalciferol (vitamin D2) due to higher bioefficacy in raising and maintaining serum 25(OH)D levels. 1, 2
Daily vs. Weekly vs. Bi-Weekly Dosing
Daily dosing is the standard recommendation for healthy children, though the evidence shows flexibility in dosing frequency. 1, 2
The half-life of 25(OH)D is 2 weeks to 3 months, and it is stored in adipose tissue, which theoretically allows for less frequent dosing schedules. 3
For treatment of deficiency (not maintenance), weekly dosing has been validated: 50,000 IU every other week for 12 weeks is equivalent to 2,000-4,000 IU daily in clinical trials. 1, 4
A randomized controlled trial in young children demonstrated that 50,000 IU vitamin D2 weekly was equivalent in efficacy and safety to 2,000 IU daily over 6 weeks. 4
However, for routine maintenance in healthy children, daily dosing of 600 IU remains the guideline-recommended approach because it ensures consistent intake and avoids the complexity of calculating weekly equivalents. 1, 2
Safety Thresholds
The upper tolerable limit for a 5-year-old (ages 4-8 years) is 3,000 IU/day, above which the risk of toxicity begins to increase. 1, 2
Vitamin D toxicity is rare at recommended doses and typically requires serum concentrations >375 nmol/L (>150 ng/mL) to cause hypercalcemia and hyperphosphatemia. 1
Practical Implementation
If the child consumes vitamin D-fortified milk, account for dietary intake: 1 liter of fortified milk provides approximately 400 IU, so supplementation should provide the remaining 200 IU to reach 600 IU total. 5
If the child is breastfed or consumes less than 1 liter of fortified milk daily, provide the full 600 IU as a supplement. 5
Vitamin D supplements are available as liquid drops (for younger children) or chewable tablets (for older children), making daily administration feasible. 5
Common Pitfalls to Avoid
Do not assume sun exposure alone is sufficient: The American Academy of Pediatrics recommends keeping children out of direct sunlight for skin cancer prevention, which may increase vitamin D deficiency risk. 5
Do not use weekly or bi-weekly dosing for routine maintenance in healthy children unless there is a specific adherence concern, as daily dosing is the evidence-based standard. 1, 2
Do not exceed age-specific upper limits (3,000 IU/day for ages 4-8 years) without medical supervision and monitoring of serum 25(OH)D levels. 1, 2