Breast milk Vitamin B12 Concentration and Incidence of Diarrhea and Respiratory Infections among Infants in Urban Tanzania: a prospective cohort study

Abstract Trials of vitamin B12 supplementation in children 6-30 months have shown an increased risk of diarrhea and respiratory infections among participants. These results are not consistent with studies in adults that showed improvement of the immune response following treatment with vitamin B12. We sought to determine how the adequacy of vitamin B12 concentrations in breast milk could act as immune modulator and protect against the incidence of diarrhea and respiratory infections of children up to 18 months in urban Tanzania. A prospective cohort study was undertaken to determine the association of milk vitamin B12 concentration with the incidence of acute respiratory infection and diarrhea among infants in urban Tanzania. A random sample of 491 women enrolled in a trial of multivitamins provided milk for B12 analysis at or around 6 weeks postpartum. Of 491 women, 345 had vitamin B12 concentrations less than the value used to define adequate intake (<310 pmol/L) in breast milk. Using generalized estimating equations, we found no overall association of milk vitamin B12 concentration with incident diarrhea and ARI in infants. Prospective studies that perform longitudinal evaluations of milk B12 concentration over time are needed to clarify the role of milk vitamin B12 in childhood infections.