ESPE Abstracts

Vitamin D supplementation is recommended for breastfed infants as primary prevention of vitamin D deficiency and nutritional rickets. Globally, the most commonly recommended dosage of vitamin D is 400 IU/day for healthy breastfed infants. Whether there are benefits of higher dosages of vitamin D to infant bone mass and body composition has been investigated. The objective of this presentation is to review the evidence from randomized controlled trials conducted in healthy term born and breastfed infants with emphasis on two trials from Montreal, Canada. In a randomized dose-response parallel group trial (clinicaltrials.gov NCT 00381914) of 400 to 1600 IU/d of vitamin D supplementation in infants (n=76 males; n=56 females) from 1 to 12 months of age, all dosages supported the primary outcome of plasma 25-hydroxyvitamin D [25(OH)D] with >97% achieving 25(OH)D ≥50 nmol/L. No differences in whole body or lumbar spine bone mass were observed among trial groups. Subsequently, a second randomized controlled parallel group trial (clinicaltrials.gov NCT02563015) was conducted in infants (n=58 males; n=40 females) born with serum 25(OH)D <50 nmol/l and randomized to 400 or 1000 IU/d of supplemental vitamin D from 1 to 12 months of age. Mean serum 25(OH)D was higher (P<0.0001) with 1000 IU/d vitamin D supplementation from 3 to 12 months of age, with no differences observed in the proportions meeting ≥50 nmol/l (400 IU/d: 93.2 to 97.5% vs. 1000 IU/d: 92.9 to 100%) between the dosage groups over time. Modest increments (4.8%) were observed in lean body mass as the primary outcome at 12 months of age (400 IU/d: 6690 ± 1122 vs. 1000 IU/d: 7013 ± 905 g, P=0.0428). The secondary outcomes of whole body and lumbar spine bone mass were not different across the trial. These trials reinforce that 400 IU/d of vitamin D supplementation is enough to build and maintain serum 25(OH)D ≥50 nmol/l and to support bone health from the neonatal period through to 1 year of age. The implications of the modest benefits of higher vitamin D status to lean body mass require further longitudinal studies. Population health and health care professionals should continue to recommend 400 IU/d of supplemental vitamin D for healthy breastfed infants in support of vitamin D status and bone health outcomes.