Vitamin B12 is low in milk of early postpartum women in urban Tanzania, and was not significantly increased by high dose supplementation

Authors: LWENO, OMAR - Ifakara Health Institute; SUDFELD, CHRISTOPHER - Harvard School Of Public Health; HERTZMARK, ELLEN - Harvard School Of Public Health; MANJI, KARIM - Muhimbili University; ABOUD, SAID - Muhimbili University; NOOR, RAMADHANI - Harvard School Of Public Health; MASANJA, HONORATI - Ifakara Health Institute; SALIM, NAHYA - Muhimbili University; Shahab-Ferdows, Setti; Allen, Lindsay - A; FAWZI, WAFAIE - Harvard School Of Public Health

Submitted to: Nutrients
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2020
Publication Date: 3/31/2020
Citation: Lweno, O.N., Sudfeld, C.R., Hertzmark, E., Manji, K.P., Aboud, S., Noor, R.A., Masanja, H., Salim, N., Shahab-Ferdows, S., Allen, L.H., Fawzi, W. 2020. Vitamin B12 is low in milk of early postpartum women in urban Tanzania, and was not significantly increased by high dose supplementation. Nutrients. 12(4). https://doi.org/10.3390/nu12040963.
DOI: https://doi.org/10.3390/nu12040963

Interpretive Summary: The effect of maternal multivitamin supplementation on breast milk vitamin B12 concentrations has not been examined in Tanzania, where the prevalence of B12 insufficiency is 25.6% based on maternal plasma B12. Multivitamins (containing 50 ug vitamin B12) or a placebo were provided during pregnancy and in the postpartum period. Breast milk samples were collected around six weeks postpartum from 491 participants in a trial of multivitamins (NCT00197548). Linear and logistic regression models were used to examine the effect of supplements on vitamin B12 concentration in milk and its associations with other variables including potential confounders. Median vitamin B12 concentration in breast milk was 206 pmol/L and 70% of women had levels indicating inadequacy (<310 pmol/L). Multivitamin supplements did not significantly reduce the odds of inadequate vitamin B12 in breast milk, suggesting suboptimal absorption. A single unit increase in maternal hemoglobin at six weeks was associated with 18% lower odds of inadequate vitamin B12 in breast milk. Participants with higher BMI at baseline had twice the odds of having inadequate vitamin B12 in milk compared to the reference group (<22 kg/m2). Trials to determine the optimal dose, route, and duration of supplementation to improve maternal B12 status in Sub-Saharan Africa are of utmost importance.

Technical Abstract: The effect of maternal multivitamin supplementation on breast milk vitamin B12 concentrations has not been examined in Tanzania, where the prevalence of maternal plasma B12 insufficiency is 25.6%. Multivitamins (containing 50 ug vitamin B12) or placebo were provided during pregnancy and in the postpartum period. Breast milk samples were collected at or around six weeks postpartum from 491 participants in a trial of multivitamins (NCT00197548). Linear and logistic regression models were used to examine the effect of supplements on vitamin B12 concentration in milk and its associations with other variables including potential confounders. Median vitamin B12 concentration in breast milk was 206 pmol/L and 70% of women had levels indicating inadequacy (<310 pmol/L). Multivitamin supplements did not significantly reduce the odds of inadequate vitamin B12 in breast milk, suggesting suboptimal absorption. A single unit increase in maternal hemoglobin at six weeks was associated with 18% lower odds of inadequate vitamin B12 in breast milk. Participants with higher BMI at baseline had double the odds of having inadequate vitamin B12 than the reference group (<22 kg/m2). Trials to determine the optimal dose, route, and duration of supplementation to improve maternal B12 status in Sub-Saharan Africa are of utmost importance.