title: Macronutrients in human milk at 2, 12, and 16 weeks postpartum.
abstract: This study evaluated changes in human milk composition from 2 to 16 weeks postpartum. Milk from 12 mothers was analyzed for lipid (utilizing a modified Folch), lactose (enzymatic hydrolysis), and nitrogen (semi-micro Kjeldahl). Energy was calculated by fractional analysis and bomb calorimetry. All samples were from well-defined subjects, and uniform collection procedures were used. Milk lipid, total nitrogen, and energy content differed significantly from one woman to another. Lipid and energy content increased from 3.98 +/- 1.0 to 5.50 +/- 1.1 gm/100 ml and 68.5 +/- 9.8 to 83.0 +/- 11.1 kcal/100 ml, respectively, and nitrogen content decreased significantly from 0.24 +/- 0.05 to 0.16 +/- 0.02 gm/100 ml from 2 to 16 weeks postpartum. Lactose remained statistically stable, increasing from 6.3 +/- 0.7 to 7.0 +/- 0.7 gm/100 ml. Estimates of energy from fractional analysis of macronutrients produced lower caloric estimates, especially at 2 weeks postpartum. Statistical differences over time and between and among mothers were found at all periods studied; therefore, on the basis of these data, we caution against reliance on single sample values as representative of mature milk either for individuals or for groups.
authors: Department of Nutritional Sciences, University of Connecticut, Storrs.
authors: A M
authors: AM
authors: Ferris
authors: M A
authors: MA
authors: Dotts
authors: R M
authors: RM
authors: Clark
authors: M
authors: M
authors: Ezrin
authors: R G
authors: RG
authors: Jensen
mesh_terms: D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008055:Lipids / Q000032:analysis; D008875:Middle Aged; D008894:Milk Proteins / Q000032:analysis*; D008895:Milk, Human / Q000032:analysis*; D013395:Sucrose / Q000032:analysis
chemical_list: D008055:Lipids; D008894:Milk Proteins; D013395:Sucrose