A nutritional supplement during preconception and pregnancy increases human milk vitamin D but not B-vitamin concentrations.

BACKGROUND & AIMS: Optimal maternal vitamin status during pregnancy and lactation is essential to support maternal and infant health. For instance, vitamin D is involved in infant bone development, and B-vitamins are involved in various metabolic processes, including energy production. Through a double-blind randomised controlled trial, we investigated the effects of maternal supplementation from preconception throughout pregnancy until birth on human milk (HM) concentrations of vitamin D and B-vitamins. In addition, we aimed to characterise longitudinal changes in milk concentrations of these vitamins.

METHODS

Both control and intervention supplements contained calcium, iodine, iron, β-carotene, and folic acid, while the intervention also contained zinc, vitamins B, B, B, and D, probiotics, and myo-inositol. HM samples were collected across 4 time points from 1 week to 3 months post-delivery from 158 mothers in Singapore, and 7 time points from 1 week to 12 months from 180 mothers in New Zealand. HM vitamin D was quantified using supercritical fluid chromatography and B-vitamins with mass spectrometry. Potential intervention effects on HM vitamins D, B, B, and B, as well as other B-vitamin (B and B) concentrations were assessed using linear mixed models with a repeated measures design.

RESULTS

Over the first 3 months of lactation, HM 25-hydroxyvitamin D concentrations were 20% (95% CI 8%, 33%, P = 0.001) higher in the intervention group, with more marked effects in New Zealand. There were no observed intervention effects on HM concentrations of vitamins B, B, B, B, and B. In New Zealand mothers, longitudinally, vitamin D concentrations gradually increased from early lactation up to 12 months, while vitamins B and B peaked at 6 weeks, B at 3 weeks, and B and B at 3 months.

CONCLUSIONS

Maternal supplementation during preconception and pregnancy increased HM vitamin D, but not B-vitamin concentrations in lactation. Further studies are required to examine the discrete benefits of vitamin D supplementation starting preconception vs during pregnancy, and to further characterise the effects of supplementation on later offspring health outcomes.

CLINICAL TRIAL REGISTRATION

Registered at ClinicalTrials.gov on the 16 July 2015 (identifier NCT02509988); Universal Trial Number U1111-1171-8056. This study was academic-led by the EpiGen Global Research Consortium.