Reference values for macronutrients in human milk

Authors: LEWIS, JACK - University Of Copenhagen; Dror, Daphna; HAMPEL, DANIELA - University Of California, Davis; KAC, GILBERTO - Universidade Federal Do Rio De Janeiro; MOLGAARD, CHRISTIAN - University Of Copenhagen; MOORE, SOPHIE - King'S College; PEERSON, JANET - Consultant; CHRISTENSEN, SOPHIE - University Of Copenhagen; ISLAM, M. MUNIRUL - Icddr,b; DE BARROS MUCCI, DANIELA - Universidade Federal Do Rio De Janeiro; DE SOUZA CAMPOS, ADRIANA - Universidade Federal Do Rio De Janeiro; HASAN, MEHEDI - Icddr,b; Allen, Lindsay

Submitted to: Advances in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: This third article in the series presenting Reference Values (RVs) for nutrients in human milk describes the values for protein, carbohydrate, fat, and energy. The RVs were developed in the Mothers, Infants and Lactation Quality (MILQ) study which collected human milk samples throughout the first 8.5 months of lactation in 1,882 well-nourished but unsupplemented women in Bangladesh, Brazil, Denmark, and The Gambia. Macronutrients were measured by near-infrared (NIR) spectroscopy. Measured macronutrient (protein, carbohydrate, fat) concentrations were compared with those used by the Institute of Medicine (IOM) for setting recommendations for nutrient requirements of infants. Protein concentration decreased from 12.4 g/L at 4-17 days to a plateau of 7.7-7.9 g/L by 4-5 months. Carbohydrate concentrations were stable throughout lactation, ranging from 68.2-70.1 g/L. Fat concentration decreased from 37.0 g/L at 4-17 days to 31.2-32.8 g/L after 2-3 months. Energy density mirrored fat trends since fat has more calories and was more variable, decreasing from 665 kcal/L at 4-17 days to 597-602 kcal/L by 3-4 months. Compared to published values, our findings were generally consistent, though slightly lower than, estimates from the Institute of Medicine (IOM) and the American Academy of Pediatrics (AAP). These RVs offer a critical resource for understanding nutritional contributions of human milk and informing public health practices to support infant growth and development.

Technical Abstract: This third article in the series presenting Reference Values (RVs) for nutrients in human milk describes the values for protein, carbohydrate, fat, and energy. The Mothers, Infants and Lactation Quality (MILQ) and Early-MILQ (E-MILQ) studies collected human milk samples throughout the first 8.5 months of lactation, in 1,882 well-nourished but unsupplemented women in Bangladesh, Brazil, Denmark, and The Gambia. Macronutrients were measured by near-infrared (NIR) spectroscopy. Measured macronutrient concentrations from the MILQ study were compared with those used by the Institute of Medicine (IOM) for setting recommendations for nutrient requirements of infants. Protein concentration decreased from 12.4 g/L at 4-17 days to a plateau of 7.7-7.9 g/L by 4-5 months. Carbohydrate concentrations were stable throughout lactation, ranging from 68.2-70.1 g/L. Fat concentration decreased from 37.0 g/L at 4-17 days to 31.2-32.8 g/L after 2-3 months. Energy density mirrored fat trends, decreasing from 665 kcal/L at 4-17 days to 597-602 kcal/L by 3-4 months. Compared to published values, our findings were generally consistent, though slightly lower than, estimates from the Institute of Medicine (IOM) and the American Academy of Pediatrics (AAP). These RVs offer a critical resource for understanding nutritional contributions of human milk and informing public health practices to support infant growth and development.