Higher Vitamin D Dosage Does Not Improve Infant Outcomes

Because vitamin D is known to play key roles in bone mineralization and immune function, researchers in Finland examined whether higher-than-standard–dose vitamin D₃ supplementation in infants improves bone strength or reduces infection frequency. They randomized 975 infants to receive either standard-dose (400 IU) or high-dose (1200 IU) vitamin D₃ daily from age 2 weeks to 24 months. Bone strength was assessed at 24 months using peripheral quantitative computed tomography. Parents reported infection frequency in diaries assessed at 6, 12, and 24 months.

Almost all infants were vitamin D–sufficient at birth (96%) and at 24 months (99%). No infants showed signs of vitamin D toxicity. Neither bone strength measures nor infection frequency diff…