499 - Human milk iodine, vitamin A and B12, and folate concentrations among women randomized to receive multiple micronutrient supplements from preconception through lactation in rural Pakistan

Poster Number: 499
Publication Number: 499.2088

Background: Exclusive human milk (HM) feeding to 6-months postpartum best supports critical early life growth and development. HM includes bioavailable and digestible micronutrients (MN) suited to infant needs; however, HM MN composition can vary with maternal MN status, and particularly with severe MN deficiency. In Pakistan, maternal MN deficiencies can be highly prevalent given dietary limitations and stunting affects 43.3% of infants by 6-months, warranting further investigation.

Objective: In a population with a high prevalence of maternal iodine, vitamin A and B12, and folate deficiency, we aimed to determine whether receiving a multiple micronutrient supplement (MMS) with these MNs changed HM concentration compared to the standard of care.

Design/Methods: Study participants included mothers of term-born infants (n=186 [intervention=97; control=89]) enrolled in the MaPPS Trial in rural Pakistan (ClinicalTrials.gov: NCT04451395) at 3-months postpartum. The MMS provided within the study was at UNIMMAP composition (Table 1). HM samples were collected from a complete breast expression from August 2020-April 2021 between 10 am-12 pm, and mothers were asked not to feed infants prior to the collection. Only infants fed HM exclusively or predominantly (i.e., water and/or non-nutritive feeds only) were eligible, and mothers receiving MMS had to report ≥50% postpartum MMS adherence. HM iodine concentration was assessed using ICP-MS; vitamin A using HPLC; vitamin B12 using chemiluminescent immunoassay (IMMULITE 2000); and folate using microbiological assay. Because the HM MN data were not normally distributed, study arms were compared using the Wilcoxon rank-sum test.

Results: Preliminary findings (median[IQR] MMS vs no MMS) show that MMS increased HM concentration for iodine (111[35,444] vs 79[48,130] μg/L; p< 0.001), vitamin A (7.9[5.2,11.0] vs 6.2 [4.2,8.9] μg/g fat; p< 0.05) and folate (63.5[55.9,82.0] vs 51.7[45.0,79.7] nmol/L; p< 0.05), but not vitamin B12 (72[53,106] vs 73[44,113] pmol/L). Importantly, few HM samples in either arm met the existing infant Adequate Intake cut-offs for the respective MNs suggested to support optimal growth and development.

Conclusion(s): Providing MN interventions while protecting exclusive HM feeding has the potential to improve outcomes in resource-limited settings with a high prevalence of MN deficiencies. We found maternal MMS increased HM iodine, vitamin A, and folate concentration, which could improve infant outcomes. There is a need to further understand the clinical implications of these findings, and whether additional concurrent interventions might be worthwhile.