Maternal diet and nutritional status during pregnancy and lactation: a review of implications on milk composition and lactation outcomes.

Maternal diet and nutritional status during lactation have important implications for human milk composition and lactation outcomes, yet the strength and consistency of these associations remain incompletely understood. This narrative review synthesizes current evidence on (1) the role of maternal dietary intake on human milk macronutrients, fatty acids, human milk oligosaccharides (HMOs), and other bioactive compounds; (2) the influence of maternal nutritional status, including body mass index (BMI), gestational weight gain, gestational diabetes, food insecurity, and biochemical nutrient markers, on milk composition; and (3) the relationship between maternal diet and nutritional status and lactation outcomes, including initiation, duration, and milk production. Methodological heterogeneity in dietary assessment, milk sampling protocols, and definitions of nutritional status limits comparability across studies. Standardized approaches and mechanistic research are needed to clarify causal pathways and identify modifiable targets to optimize milk composition and support successful lactation.