Carbohydrate content of human milk is affected by seasonal variations: a retrospective observational study.

Objective: The influence of seasonal variation upon human milk macronutrient content has not been elucidated. This study aimed to compare the macronutrient content of HM produced by lactating mothers during the winter and the summer seasons.

Study Design: Macronutrient content of colostrum milk samples collected from lactating mothers of healthy term infants between March 2012 and February 2016 was measured by mid-infrared spectroscopy and compared.

Result: The carbohydrate content of the colostrum was significantly higher in the summer season than in the winter season (6.2 ± 1.3 vs. 5.5 ± 1.4, p-value < 0.001). Protein, fat, and energy contents were similar in summer and winter in both groups (protein 2.7 ± 2.1 vs. 2.6 ± 2.2 g/100 ml, fat 2.6 ± 1.9 vs. 2.35 ± 1.9 g/100 ml, and energy 62 ± 19.1 vs. 60.5 ± 21 kcal/100 ml, respectively).

Conclusion: The carbohydrate content in colostrum obtained from mothers of term infants was affected by seasonal variations.