The effects of prenatal and postnatal high-dose vitamin B-12 supplementation on human milk vitamin B-12: a randomized, double-blind, placebo-controlled trial in Tanzania

Authors: WAND, DONGQING - George Mason University; Shahab-Ferdows, Setti; LWENO, OMAR - Ifakara Health Institute; HAMPEL, DANIELA - University Of California, Davis; METHOD, BALAMA - Muhimbili University; YELVERTON, CARA - Harvard University; NGUYEN, CHRISTINE - George Mason University; ABOUD, SAID - Muhimbili University; Allen, Lindsay - A; FAWZI, WAFAIE - Harvard University

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/31/2023
Publication Date: 8/31/2023
Citation: Wand, D., Shahab-Ferdows, S., Lweno, O.N., Hampel, D., Method, B., Yelverton, C.A., Nguyen, C.H., Aboud, S., Allen, L.H., Fawzi, W.W. 2023. The effects of prenatal and postnatal high-dose vitamin B-12 supplementation on human milk vitamin B-12: a randomized, double-blind, placebo-controlled trial in Tanzania. The American Journal of Clinical Nutrition. https://doi.org/10.1016/j.ajcnut.2023.07.023.
DOI: https://doi.org/10.1016/j.ajcnut.2023.07.023

Interpretive Summary: Vitamin B-12 in human milk (HM) is important for infant growth and development. Only a few reports have separately evaluated the effects of prenatal and postnatal maternal high-dose vitamin B-12 supplementation on HM vitamin B-12 concentration. Therefore, we analyzed HM vitamin B-12 concentrations at six weeks (n = 877) and seven months (n = 444) postpartum from HIV-negative mothers participating in a maternal multiple micronutrient supplementation trial in Tanzania. From recruitment (during 12 to 27 weeks of gestation) through 6 weeks postpartum, participants were randomized to receive daily oral multiple micronutrient supplementation, containing 50 µg/d of vitamin B-12, or a placebo. From 6 weeks to 18 months postpartum, a subset of participants received postnatal supplement or placebo. We found that the prevalence of HM vitamin B-12 less than 310 pmol/L was 71.6% and 68.2% at six weeks and seven months postpartum, respectively. Prenatal supplementation significantly increased HM B-12 concentration and reduced the risk of HM B-12 less than 310 pmol/L (P < 0.001) at six weeks postpartum; this effect was no longer significant at seven months postpartum. Postnatal supplementation significantly increased HM vitamin B-12 concentration and reduced the risk of HM B-12 less than 310 pmol/L at seven months postpartum. In conclusion, continued vitamin B-12 supplementation from pregnancy through lactation may be important to the sustained status of vitamin B-12 in populations with low dietary intake of vitamin B-12.

Technical Abstract: Background: Vitamin B-12 status in human milk (HM) has critical implications for infant growth and development. Few studies have separately examined the effects of prenatal and postnatal maternal high-dose vitamin B-12 supplementation on HM vitamin B-12 concentration. Methods: Data from a randomized, double-blind, placebo-controlled trial of maternal multiple micronutrient supplementation in Tanzania were used. HIV-negative pregnant women were enrolled in antenatal clinics in Dar es Salaam, Tanzania, between 2001 and 2004. From recruitment (during 12 to 27 weeks of gestation) through 6 weeks postpartum, participants were randomized to receive daily oral multiple micronutrient supplementation or a placebo. From 6 weeks to 18 months postpartum, a subset of participants was randomized to postnatal supplement or placebo. The supplement included 50 µg/d of vitamin B-12 and various other vitamins. HM vitamin B-12 concentrations were analyzed at six weeks (n = 877) and seven months (n = 444) postpartum. Linear and log-binomial models were used to examine the effects of prenatal and postnatal vitamin B-12 supplementation on HM vitamin B-12. Results: The prevalence of HM vitamin B-12 less than 310 pmol/L was 71.6% and 68.2% at six weeks and seven months postpartum, respectively. Prenatal supplementation significantly increased HM B-12 concentration (adjusted percent difference: 20.1; 95% CI: 9.72, 31.5; P < 0.001) and reduced the risk of HM B-12 less than 310 pmol/L (adjusted RR: 0.83; 95% CI: 0.75, 0.91; P < 0.001) at six weeks postpartum; this effect was no longer significant at seven months postpartum. Postnatal supplementation significantly increased HM vitamin B-12 concentration (adjusted percent difference: 15.5; 95% CI: 1.66, 31.3; P = 0.027) and reduced the risk of HM B-12 less than 310 pmol/L (adjusted RR: 0.83; 95% CI: 0.73, 0.95; P = 0.009) at seven months postpartum. Conclusions: Continued vitamin B-12 supplementation from pregnancy through lactation may be important to the sustained status of vitamin B-12 in populations with low dietary intake of vitamin B-12.