(P18-050-23) Milk B Vitamin Response to Supplementation With Multiple Micronutrients Versus Iron-Folic Acid During Pregnancy Through 3 Months Postpartum in Rural Bangladesh

Objectives: Many B vitamin concentrations in human milk reflect maternal dietary intakes or status and may therefore be insufficient to meet current dietary intake recommendations for infants in undernourished populations. We examined effects of daily antenatal multiple micronutrient supplementation (MMS) with 1 RDA of 15 nutrients, including B vitamins, on milk thiamin, riboflavin, niacin, and vitamin B6 in Bangladeshi women and compared milk B vitamin concentrations to those used to set the infant Adequate Intake (AI) recommendations.

Methods: In a cluster-randomized trial of antenatal MMS vs iron-folic acid (IFA) as control, we collected a casual sample of milk in a substudy at 3 months of lactation, when supplementation ceased. Vitamers of thiamin, riboflavin, niacin, and vitamin B6, among others, were analyzed by LC-MS/MS in n=433 (n=235 IFA, n=198 MMS) samples. Differences in milk B vitamins by intervention group were examined after accounting for cluster randomization. Milk B vitamin concentrations were compared to those used to set AI recommendations for infants 0-6 months of age.

Results: With MMS compared to IFA, milk total thiamin did not differ (179±42 μg/L vs 182±43 μg/L, p=0.6), although free thiamin was 30.7 (95% CI: 19.4, 41.3)% higher (45±25 vs 34±17 μg/L, p< 0.0001). Total riboflavin was 59.7 (43.3, 76.1)% higher (80±47 vs 50±30 μg/L), and total niacin 22.4 (11.0, 33.9)% higher (1685±845 vs 1376±662 μg/L), both p< 0.0001, with all forms of both vitamins higher with MMS than IFA. Total vitamin B6 was 15.9 (6.4, 25.4)% higher (159±65 vs 137±50 μg/L, p=0.001), with pyridoxal higher, pyridoxamine lower, and pyridoxine and pyridoxal-5-phosphate not different with MMS. Percent of milk samples achieving B-vitamin concentrations used to set infant AIs was, by MMS and IFA, respectively: thiamin>210 μg/L, 22.4 vs 23.4%; riboflavin >350 μg/L, 0.5 vs 0.0%; niacin >1800 μg/L, 30.3 vs 16.6%; vitamin B6 >130 μg/L, 62.9 vs 51.1%; significantly greater with MMS for niacin (p=0.002) and vitamin B6 (p=0.03) only.

Conclusions: Antenatal MMS taken to 3 months postpartum increased B vitamins in milk of rural Bangladeshi women. Yet, B vitamin concentrations, except for B6, remained substantially lower than the concentrations used to set infant AIs, suggesting potential inadequacy among Bangladeshi infants.

Funding Sources: Bill and Melinda Gates Foundation and USDA, ARS