Maternal dietary intake, nutritional status and macronutrient composition of human breast milk: systematic review

Abstract
Introduction: Human breast milk is the best source of nutrition in early life, particularly during the first six months. Nevertheless, human breast milk composition is variable and more insight in the exact factors contributing to this variability is warranted. In this review, we explored the impact of maternal dietary intake and nutritional status (e.g., anthropometric measures, body mass index, bioimpedance) on human milk macronutrient composition. Method: PubMed, Scopus and Cochrane were systematically searched till November 2019. Results: In total, 4946 publications underwent title-abstract screening; 101 publications underwent full-text screening. Eventually, 50 publications were included in this review, investigating either associations between maternal dietary intake (n=29) and/or maternal nutritional status (n=29), and macronutrient composition of human breast milk. Reported energy composition ranged from 51-72 kcal/dl, and 67% and 54% of the studies reported associations between with maternal nutritional intake and status, respectively. Protein content ranged from 0.8-3.3g/dl and four studies suggested a negative association with nutritional status. Fat content ranged from 2.1- 9.8g/dl, and 68% of the studies reported positive associations with nutritional status. Carbohydrate content ranged from 5.8-7.5g/dl, and 67% of the included studies did not report an association between intake or status. Conclusion: Literature investigating associations of maternal dietary intake and nutrition status with breast milk composition of macronutrients and energy content is diversified, both in terms of used methodology as well as results. Further studies using well defined and standard parameters are essential to aid the formulation of scientific recommendations.