(PTFS07-01-25) The Effects of Prenatal High-Dose Multiple Micronutrient Supplementation on B Vitamins in Human Milk: a Randomized Controlled Trial in Tanzania

Objectives: The adequacy of B vitamins in human milk is critical for infant growth and development. The impact of prenatal multiple micronutrient supplementation (MMS) on many B vitamins in human milk remains unclear. This work aimed to assess the effects of prenatal MMS on human milk B vitamins, including vitamins B-1, B-2, B-3, B-6, and B-12, at six weeks postpartum.

Methods: Data from a randomized, double-blind, placebo-controlled trial of MMS among pregnant and lactating women in Dar es Salaam, Tanzania, were used. Pregnant women of 12 to 27 weeks of gestation were enrolled and randomly assigned to daily oral high-dose MMS or placebo through 6 weeks after delivery. The MMS tablet included 20 mg/d of vitamin B-1 (thiamin), 20 mg/d of vitamin B-2 (riboflavin), 100 mg/d of vitamin B-3 (niacin), 25 mg/d of vitamin B-6 (pyridoxine), and 50 μg/d of vitamin B-12 (cobalamin) and various other vitamins. The dosage of the supplement provided 6 to 19 times the recommended dietary allowance for pregnant women for vitamins B-1, B-2, B-3, B-6, and B-12. Human milk concentrations of these B vitamins at six weeks were analyzed for 434 participants (246 in the MMS arm and 188 in the control arm). Linear models were used to compare human milk B vitamin concentrations between MMS and placebo arms while adjusting for potential confounders.

Results: After adjusting for covariates, compared to prenatal placebo, prenatal high-dose MMS increased human milk concentrations of vitamin B-1 by 39% (95% CI: 25, 55; P < 0.001), vitamin B-2 by 92% (95% CI: 62, 127; P < 0.001), vitamin B-3 without nicotinic acid by 48% (95% CI: 21, 81; P < 0.001), vitamin B-6 by 42% (95% CI: 25, 61; P < 0.001), and vitamin B-12 by 21% (95% CI: 4, 41; P: 0.012) at six weeks postpartum.

Conclusions: Prenatal high-dose MMS confers beneficial effects on the human milk concentrations of vitamins B-1, B-2, B-3, B-6, and B-12. Micronutrient supplementation during pregnancy and lactation remains an important strategy for sustaining maternal micronutrient adequacy in settings with suboptimal dietary intake and high burdens of micronutrient deficiencies.

Funding Sources: This work was supported by the Bill and Melinda Gates Foundation.