Oral Calcium Dosing in Children by Body Weight
For oral calcium supplementation in children, the recommended dose ranges from 10-16 mg/kg/day for children 1-18 years, with total daily intake (diet plus supplements) targeted at 100-200% of the age-specific Dietary Reference Intake (DRI). 1
Age-Specific Oral Calcium Requirements
Infants and Young Children
- Infants 0-6 months: 400 mg/day total intake 2
- Infants 6-12 months: 600 mg/day total intake 2
- Children 1-5 years: 800 mg/day total intake 2
- Children 6-10 years: 800-1,200 mg/day total intake 2
Adolescents and Young Adults
- Ages 11-24 years: 1,200-1,500 mg/day total intake 2
- This age group requires higher intake due to peak bone mass acquisition during puberty 3
Weight-Based Dosing Framework
When calculating supplementation needs, use 10-16 mg/kg/day as the baseline for children 1-18 years 1, but always consider:
- Total oral intake should equal 100-200% of age-specific DRI 3
- The lower end (100% DRI) is appropriate for children with normal dietary calcium intake 3
- The upper end (200% DRI) represents the maximum safe limit, approximately 2,500 mg/day for children ≥9 years 3
Practical Calculation Example
For an 8-year-old child weighing 25 kg with dietary calcium intake of 700 mg/day:
- Age-appropriate DRI: 800-1,200 mg/day 2
- Maximum total intake: 1,600 mg/day (200% of DRI) 3
- Supplementation needed: 100-500 mg/day (to reach 800-1,200 mg total) 3
Special Populations
Children with Chronic Kidney Disease (CKD)
- Total oral calcium intake (diet + binders) should be 100-200% of DRI for age 3
- Calcium-containing phosphate binders must be counted toward total calcium intake 3
- For example, a dialyzed 8-year-old with 700 mg dietary calcium can receive maximum 900 mg elemental calcium from binders (total 1,600 mg = 200% DRI) 3
Children on Glucocorticoid Therapy
- Ages 4-17 years on glucocorticoids ≥3 months: optimize to 1,000 mg/day total intake 3
- This is a conditional recommendation due to limited antifracture efficacy data in children 3
Treatment of Rickets
- Elemental calcium 70-80 mg/kg/day for premature neonates 4
- 500-800 mg/day for all children >1 year with rickets 4
Forms of Calcium Supplements
The elemental calcium content varies significantly by salt form 3, 5:
- Calcium carbonate: 40% elemental calcium (most cost-effective; take with meals) 3, 6
- Calcium acetate: 25% elemental calcium 3, 5
- Calcium lactate: 13% elemental calcium 3, 5
- Calcium gluconate: 9% elemental calcium 3, 5
Maximum single dose: 500 mg elemental calcium 6 - divide daily doses accordingly for optimal absorption.
Critical Pitfalls to Avoid
- Never use calcium chloride as an oral supplement - it can cause metabolic acidosis, especially in CKD patients 3
- Avoid calcium citrate in CKD patients - it enhances aluminum absorption 3
- Do not exceed 2,500 mg/day total intake in children ≥9 years (approximately 200% of DRI) 3, 2
- Account for dietary calcium - spontaneous intake is often 700-800 mg/day in school-age children 3
- Consider phosphorus content - high-calcium dairy products contain significant phosphorus, which may be problematic in children requiring phosphorus restriction 3