Human-milk vitamin B-3 (niacin and vitamer) concentrations: Secondary analysis of a randomized, placebo-controlled trial of maternal nicotinamide supplementation in rural Tanzania

Authors: DEBOER, MARK - University Of Virginia; MCDERMID, JOANN - University Of Virginia; HAMPEL, DANIELA - University Of California, Davis; Shahab-Ferdows, Setareh; MAZZONI, GABRIELLE - University Of Virginia; PEERSON, JANET - Consultant (USA); ELWOOD, SARAH - University Of Virginia; SCHARF, REBECCA - University Of Virginia; JATOSH, SAMWEL - Haydom Lutheran Hospital; PLATT-MILLS, JAMES - University Of Virginia; MDUMA, ESTOMIH - Haydom Lutheran Hospital; Allen, Lindsay

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2026
Publication Date: 6/17/2026
Citation: DeBoer, M.D., McDermid, J.M., Hampel, D., Shahab-Ferdows, S., Mazzoni, G., Peerson, J.M., Elwood, S.E., Scharf, R.J., Jatosh, S., Platt-Mills, J.A., Mduma, E., Allen, L.H. 2026. Human-milk vitamin B-3 (niacin and vitamer) concentrations: Secondary analysis of a randomized, placebo-controlled trial of maternal nicotinamide supplementation in rural Tanzania. The American Journal of Clinical Nutrition. 124(2). Article 101397. https://doi.org/10.1016/j.ajcnut.2026.101397.
DOI: https://doi.org/10.1016/j.ajcnut.2026.101397

Interpretive Summary: In regions where maize is the dominant part of the diet, people are at higher risk of vitamin B3 (niacin) deficiency, if its bioavailability is not improved through food preparation practices and with low consumption of niacin-rich animal, seafood or fortified foods. The consequences for breastmilk vitamin B3 concentrations under such conditions, which are common to many rural regions,particularly in southern and eastern Africa, are uncertain. Here, in the ELICIT study, based around Haydom, Tanzania, lactating women were randomized to receive a nicotinamide supplement (250 mg/d vs. placebo) from study entry (infant age <2 weeks) until 6-months (n = 1177). Breastmilk nicotinamide and B3 vitamer concentrations were analyzed in milk samples collected at 1 and 5 months postpartum and were compared to international reference ranges. Child anthropometry and cognitive development (Malawi Developmental Assessment Tool, MDAT) relationships were assessed. We found that without maternal nicotinamide supplementation, more milk samples revealed decreasing total vitamin B3 concentrations below the lower reference limit (month 1=3%; month 5=26%). Maternal supplementation was associated with many milk total vitamin B3 concentrations exceeding the upper reference limit (month 1=74%; month 5=40%), and the magnitude of difference in concentrations between supplemented and non-supplemented increased over time (month 1=190%; month 5=309%). No relationship was found between milk total vitamin B3 or vitamer concentrations and child weight, height or head circumference up to 18 months or with MDAT scores at 18 months. Thus, without maternal nicotinamide supplementation, lactating women are at greater risk of breastmilk total vitamin B3 concentrations below the reference range. Although supplementation was associated with higher total vitamin B3 and all vitamer concentrations, there was no relationship with child growth or development. The implications of strategies to improve breastmilk vitamin B3 concentrations in women at risk of low breastmilk vitamin B3 and vitamin B3 undernutrition should be considered.

Technical Abstract: Background: The risk of vitamin B3 (niacin) deficiency is increased if the staple maize is consumed without improving the bioavailability through food preparation practices and with limited consumption of niacin-rich animal, seafood or fortified foods. The implications for breastmilk vitamin B3 concentrations in this maternal dietary context common to many rural regions, particularly in southern and eastern Africa, are uncertain. Methods: The ELICIT study, based around Haydom, Tanzania, randomized lactating women to supplemental nicotinamide (250 mg/d vs. placebo) from study entry (infant age <2 weeks) until 6-months. Among 1177 mother/child dyads, breastmilk nicotinamide and B3 vitamer concentrations at lactation months 1 and 5 were compared to international reference ranges, and child anthropometry and cognitive development (Malawi Developmental Assessment Tool, MDAT) relationships assessed. Results: Without maternal nicotinamide supplementation, the proportion of breastmilk total vitamin B3 concentrations below the lower reference limit increased over time (month 1=3%; month 5=26%). Maternal nicotinamide supplementation was associated with many breastmilk total vitamin B3 concentrations exceeding the upper reference limit (month 1=74%; month 5=40%), and the magnitude of difference in concentrations between those supplemented or receiving placebo increased over time (month 1=190%; month 5=309%). No associations were observed between breastmilk total vitamin B3 or vitamer concentrations and child weight, height or head circumference up to 18 months or with MDAT scores at 18 months. Conclusions: Without maternal nicotinamide supplementation, lactating women had a greater prevalence of breastmilk total vitamin B3 concentrations below the reference range. Although supplementation was associated with greater total vitamin B3 and all vitamer concentrations, there was no association with child growth or development outcomes up to 18 months. The implications of strategies to improve breastmilk vitamin B3 concentrations in women at risk of low breastmilk vitamin B3 and vitamin B3 undernutrition should be considered.