Breast milk from mothers of very low birthweight infants: variability in fat and protein content

While breast milk appears to be superior to formula for the development of very low birthweight (VLBW) infants, it is supplemented to meet the metabol ic demands of the rapidly growing premature infant. To estimate the nutriti onal variability of breast milk from mothers of VLBW infants, protein (bici nchoninic acid method) and fat content (creamatocrit) were measured in brea st-milk spot samples from mothers of 20 VLBW infants, collected 4 times I a day during the first 4 wk of lactation. Protein content (median 1.9 g dl(- 1), range 1.1-3.5 g dl(-1)) and fat content (3.8/1.0-14.6 g dl(-1)) were hi ghly variable and lacked a normal distribution over all samples and in indi vidual women's milk. There was only a weak correlation between fat and prot ein (r(s) = 0.416, p < 0.001). Fat but not protein was lower in morning sam ples than in samples collected later in the day (p < 0.001). Protein but no t fat content decreased during the weeks of lactation (r(s) = -0.446, p < 0 .001). No impact of the baby's gestational age was observed. Conclusion: The fat and protein content of breast milk from mothers of VLBW infants is highly variable, calling into question the clinical feasibility of individualized supplementation of breast milk for VLBW infants based on spot sample measurements.