800 IU versus 400 IU per day of vitamin D 3 in term breastfed infants: a randomized controlled trial from an LMIC.

This open-label, block-randomized controlled trial compared the effect of 800 IU/day and 400 IU/day of oral vitamin D ₃ supplementation in reducing vitamin D insufficiency (VDI) among healthy-term breastfed infants at 14 weeks of postnatal age. All eligible infants were randomized to receive either 800 or 400 IU/day of oral vitamin D ₃ (starting within the first week until 14 weeks). The primary outcome was the proportion of infants with VDI (25-OH-D < 20 ng/ml) at 14 weeks. Secondary outcomes were vitamin D deficiency (VDD, < 12 ng/ml), severe VDD (< 5 ng/ml), anthropometry, biochemical or clinical rickets, and any adverse events related to vitamin D toxicity (VDT). Among 102 enrolled infants, the distribution of baseline variables (including cord 25-OH-D levels; 13.0 versus 14.2 ng/ml) was similar in both groups. On intention-to-treat analysis, the proportions of infants with VDI at 14 weeks were significantly lower in the 800 IU group compared to those in the 400 IU group [24% versus 55%; RR 0.44; 95% CI: 0.25-0.76]. The proportions of infants with elevated parathormone (6% versus 26.5%; p = 0.012) and severe VDD (0% versus 12.2%; p = 0.033) were significantly lower in the 800 IU group. Clinical rickets developed in three (6.2%) infants in the 400 IU group. No infant developed VDT.      Conclusions: Daily oral supplementation with 800 IU of vitamin D ₃ resulted in an almost 50% reduction in the proportion of infants with VDI and prevented the occurrence of severe VDD at 14 weeks of age compared to 400 IU with no evidence of vitamin D toxicity.     Trial Registration: Clinical Trial Registry of India (CTRI/2019/02/017374). What is Known: • Breastfeeding is the ideal source of nutrition for healthy-term breastfed infants; however, vitamin D content of breastmilk is suboptimal. • AAP recommends daily oral supplementation of 400 IU of vitamin D to all healthy-term breastfed infants; however, trials from high-income countries support insufficiency of this dose in maintaining serum 25-OH-D levels >20 ng/ml with no such information from low-middle-income countries. What is New: • 800 IU/day of oral vitamin D3 supplementation among term breastfed infants significantly reduces vitamin D insufficiency at 14 weeks' age as compared to the recommended dose of 400 IU/day. • This higher supplemental dose is safe with no evidence of vitamin D toxicity.
(© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)