Breast Milk Intake from 1 to 8.5 Months of Lactation in the Multisite Mothers, Infants and Lactation Quality (MILQ) Study

Human milk from healthy, well-nourished women is the optimal nutrition for infants and young children, and exclusive breastfeeding is recommended for the first 6 mo. In the context of poor diets, the quality of milk may be compromised, and understanding the relationships between maternal diet, human milk nutrient concentrations, and milk intakes in young infants is important for guiding policy. The Mothers, Infants, and Lactation Quality (MILQ) study collected human milk samples from 1 to 8.5 mo of lactation in 558 well-nourished but unsupplemented women in Bangladesh, Brazil, Denmark, and The Gambia. Milk intakes were measured at 3 visits postnatally (1–3.49 mo, 3.5–5.99 mo, and 6.0–8.5 mo). Milk intakes were assessed in 3 sites (Bangladesh, Brazil, and The Gambia) using the stable isotope dilution dose-to-mother method. In Denmark, intakes were measured by test weighing, and volume data were corrected by a factor of 1.05 to account for insensible water losses. The mean ± standard deviation human milk intake across sites and time points was 781 ± 193 g/d. Milk intakes were comparable among sites early in lactation, but as intakes decreased across lactation, between-site differences emerged as nonmilk feeds were introduced. Exclusively breastfed infants consumed greater volumes of milk each day than mixed-fed infants. When expressed against infant body weight, a gradual decrease in milk intake was observed across lactation. Milk nutrient concentrations were largely unrelated to daily milk intakes. Therefore, correlations between milk nutrient concentrations and total daily intake of nutrients were mostly positive and strong. Mean milk intake in the MILQ study was consistent with previously published global data, although variability was observed across lactation and between contexts. Infants consuming greater milk volumes had greater daily intakes of milk nutrients. The implications for infant status and recommended nutrient intakes require further investigation.