Abstract
Aim: Few longitudinal data are available on macronutrient breast milk composition during lactation. There are no studies from Italian lactating mothers.
Methods: Thirty lactating mothers (enrolled according to major criteria of normality for mother, delivery and infant) were followed up to 6 months of delivery. Breast milk samples were taken at 1 (T1), 2, 3, 6 (T6) months, at the first feeding in the morning. Fore- and hind milk were collected and frozen (-20 C) until analysis, when were mixed. Total fats were determinated gravimetrically and fatty acid (FA) methyl esters extracted from lipids according to Folch were separated by GLC. Total protein and carbohydrate content were evaluated by turbidimetric assay and HPLC, respectively. Breast milk macronutrient concentrations were further categorized in tertiles. Statistics: Analysis of variance for repeated measures and Friedman test. Significance: P<0.05.
Results: Concentration of breast milk macronutrients changed significantly over time for protein (P<0.0001), total fat (P=0.026) but not for lactose (P=0.169). Among total fat, variation was significant for saturated FA (P=0.022) but not for either monounsaturated (P=0.189) or polyunsaturated (P=0.218) FA. Significance of difference between T6 and T1 was P<0.0001 (mean [SD], 9.6 [1.6] vs 11.6 [1.5] g/l) for protein and P=0.05 (mean [SD], 27.1 [12.5] vs 32.0 [12.7] g/l) for total fat. No significant longitudinal within-subject change was found with respect to tertiles of any macronutrient concentration (protein, P=0.47; fat, P=0.96; lactose, P=0.89).
Conclusions: In this study we have found a reduction in breast milk protein concentrations over time, in agreement with previous studies. Differently than other studies, we further have found significant variation in total fat concentrations. The lack of a specific, detectable within-subject trend in pattern of macronutrients in breast milk confirms that many factors may influence the milk composition in the first six months of lactation.
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Giovannini, M., Scaglioni, S., Verduci, E. et al. 400 Longitudinal Pattern of Macronutrients in Breast Milk During the First Six Months of Breastfeeding: An Italian Study. Pediatr Res 58, 423 (2005). https://doi.org/10.1203/00006450-200508000-00429
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DOI: https://doi.org/10.1203/00006450-200508000-00429