B-Vitamins and Choline in Human Milk Are Not Impacted by a Preconception Lipid-Based Nutrient Supplement, but Differ Among Three Low-to-Middle Income Settings-Findings From the Women First Trial

Abstract

Introduction: Optimal human milk (HM) B-vitamin concentrations remain undefined, especially in areas where undernutrition is prevalent. The impact of supplementation pre-conception through pregnancy on HM B-vitamin composition remains unknown. Methods: Human milk (HM) was collected at 2-weeks postpartum from 200 women in Guatemala, India, and Pakistan (the Women First Trial). The women were randomized to start a lipid-based nutrient supplement before conception, at end of the first trimester, or not at all; intervention continued until delivery. HM concentrations of eight B-vitamins and choline were assessed via ultra-performance liquid chromatography-tandem mass spectrometry. Maternal diet was assessed in early pregnancy, and infant growth followed through 6 months post-delivery. Results: Despite supplement exposure averaging 15.7 (pre-conception arm) and 6.0 months (prenatal arm), HM B-vitamins did not differ between arms, but site differences were evident. Guatemala had higher HM concentrations of vitamin B3 than Pakistan and India. Pakistan had higher HM concentrations of thiamin and vitamin B6 than India and Guatemala. Cohort average HM vitamin B2 (162 ± 79 μg/L) and B6 (31.8 ± 24.6 μg/L) fell below values defined as deficient in 81.5 and 85.5% of samples, potentially reflecting sampling procedures and timing. Maternal dietary intakes of only vitamin B6 and choline were associated with the corresponding concentrations in HM (p < 0.005). No HM B-vitamin concentrations were associated with infant growth. Conclusion: Prenatal supplementation for at least 6 months had no impact on HM B-vitamin concentrations at 2-weeks postpartum. Results suggest that the adequacy of HM composition was generally maintained, with potential exceptions of vitamin B2 and B6.

Keywords: B vitamins; human milk; infant growth; lipid nutrient supplement (LNS); nutrition intervention; thiamin; vitamin B12.

Figure 1

Human milk (HM) B-vitamin concentrations at 2-weeks postpartum by site. Shown are the mean ± SD of the concentration of human milk B-vitamins at 2-weeks. Solid gray lines represent the concentration in human milk used to set the Adequate Intake (AI) (21), the dietary reference intake for infants 0–6 months in the USA, assuming an intake of 780 ml per day. Dashed gray lines represent concentrations in human milk associated with a deficiency in the recipient exclusively breastfed infant for thiamin, vitamin B2, B6, B12, and choline, summarized in Allen et al. (4). Estimated total thiamin concentration based on free thiamin measurement and previously published adjustment factor at 2–6-week human milk (19). ¹One outlier excluded from the reported mean; ²Two outliers excluded from the reported mean; ³Three outliers excluded from the reported mean; ⁵Five outliers excluded from the reported mean; Differences between sites were assessed via ANOVA and Wilcoxon Rank Sum Test in normally distributed and non-normally distributed variables, respectively. When p < 0.0001, significant differences between individual sites were assessed via Tukey's Test and are indicated by different letters.