The macronutrient composition of breas tmilk from Mexican mothers in the first six months postpartum: Influence of maternal factors and potential effects on infant anthropometry

The relationship between maternal obesity, age, and the macronutrient concentrations in breast milk is unclear. This study aimed to investigate whether the macronutrient composition of breast milk is influenced by maternal adiposity and age, as well as how these factors impact infant growth during the first six months of life. The concentrations of lipids, proteins, and carbohydrates in colostrum, transition milk, and mature milk were measured in samples from 118 mothers. The total body fat (TBF) was determined, and mothers were categorized as adequate (ATBF, ≤30 %) or elevated (ETBF, >30 %) and further classified by age as younger (less than 30 years) or older (more than 30 years). Infant anthropometric measurements were also taken. The concentrations of all macronutrients in mature breast milk were significantly higher (p < 0.05) in the ETBF and older mother groups compared to the ATBF and younger groups. Maternal age was positively associated (R² = 0.099, p = 0.034) with the concentration of lipids in colostrum. There was a negative correlation (p < 0.05) between macronutrient levels and the infant's weight and head circumference in the ATBF group. Maternal adiposity and age were linked to higher levels of macronutrients in mature breast milk. These levels were found to be greater in mature breast milk compared to colostrum, but this was only observed in women under 30 years old. Low levels of macronutrients in breast milk were associated with increases in infants' weight and head circumference, only in lean mothers.