Vitamin D Supplementation: Could Infants Benefit from a Higher Dosage?

Administering a higher dosage of supplemental vitamin D3 to infants likely does not provide any additional benefit for bone strength or infection protection compared with a standard dosage, according to a new study.

A total of 975 healthy term infants born at a maternity hospital in Helsinki, Finland were included in the study. Follow-up lasted until May 30, 2016.

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Each infant was randomly assigned to daily oral vitamin D3 supplementation at a standard dosage of 400 IU (n = 489) or a higher dosage of 1200 IU (n = 486) from age 2 weeks to 24 months.

Bone strength and the incidence of parent-reported infections at 24 months comprised the main outcome.

Ultimately, 823 (84.4%) infants completed the 24-month follow-up. Data from the study revealed that there were no between-group differences in bone strength measures, including:

  • Bone mineral content (mean difference 0.4 mg/mm)
  • Mineral density (mean difference 2.9 mg/cm3)
  • Cross-sectional area (mean difference -0.9 mm2)
  • Polar moment of inertia (mean difference -66.0 mm4)

No between-group differences were observed in the incidence rates of parent-reported infections (incidence rate ratio of 1.00).

The researchers noted that 914 (95.7%) infants were vitamin D sufficient at birth, and that mean 25(OH)D concentration was higher in the 1200-IU group vs the 400-IU group at 24 months (mean difference 12.50 ng/mL).

“Daily supplementation with 400 IU vitamin D3 seems adequate in maintaining vitamin D sufficiency in children younger than 2 years,” the researchers concluded.

—Christina Vogt


Rosendahl J, Valkama S, Holmlund-Suila E, et al. Effect of higher vs standard dosage of vitamin D3 supplementation on bone strength and infection in healthy infants: a randomized clinical trial. JAMA Pediatr. 2018;172(7):646-654. doi:10.1001/jamapediatrics.2018.0602