A pilot study of synbiotic supplementation on breast milk mineral concentrations and growth of exclusively breast fed infants

Despite the crucial role of breast milk mineral contents for health and growth of the infants, they decrease with the duration of lactation. So, this pilot study aimed to determine the effects of synbiotic supplementation on breast milk mineral composition and infants’ growth. In this pilot, randomized, double-blind, placebo-controlled trial, 57 lactating mothers were randomly divided into two groups to receive a daily supplement of synbiotic (n = 30) or a placebo (n = 27) for 30 days. Breast milk zinc, copper, Iron, magnesium and, calcium concentrations were determined by flame atomic absorption spectrometry. Weight for age Z-score (WAZ) and height for age Z-score (HAZ) were assessed for infants. Dietary intake was collected from lactating women using the 24-h recall method. Data analyses were carried out using nutritionist IV, Epi Info and SPSS soft wares. Synbiotic supplementation led to an insignificant increase of the mean breast milk levels of zinc (from 2.44 ± 0.65 to 2.55 ± 0.55 mg L−1), copper (from 0.35 ± 0.24 to 0.40 ± 0.26 mg L−1), iron (from 0.28 ± 0.42 to 0.31 ± 0.38 mg L−1), magnesium (from 17.14 ± 1.35 to 17.17 ± 1.09 mg L−1), and calcium (from 189 ± 25.3 to 189.9 ± 21.7 mg L−1); whilst in the placebo group, these variables decreased significantly (P = 0.001). The observed changes between two groups were statistically significant (P < 0.05). Although WAZ and HAZ of infants increased slightly in the supplemented group (from 1.19 ± 0.79 to 1.20 ± 0.69 and 0.36 ± 0.86 to 0.37 ± 0.85 respectively), these two parameters decreased in the placebo group which was significant only for WAZ (P = 0.01). Moreover, no significant association was found between mineral intake and breast milk mineral contents. It seems, synbiotic supplementation may have positive effects on breast milk mineral contents.