Fatty acid balance studies in premature infants fed human milk or formula: effect of calcium supplementation.

During the first 4 neonatal weeks, serial total fatty acid and individual fatty acid balance studies were completed in 35 healthy premature infants with appropriate weight for gestational age. Infants weighed less than 1500 gm at birth, were descriptively similar, and were receiving similar volumes of either preterm mothers' milk (PTM) or formula (S-M-A 20). Total fatty acid and major fatty acid contents of the two feeding regimens were similar. Total fecal output and total fatty acid excretion were higher, whereas subsequent total fat absorption and coefficient of absorption were significantly lower, in the group fed S-M-A 20 (P less than 0.001). Administration of oral calcium supplements fed as calcium lactate (1.5 to 2.0 mmol/kg/day) decreased total fatty acid absorption in both the PTM (P less than 0.01) and S-M-A 20 (P less than 0.001) groups. Furthermore, the effect of feeding (P less than 0.0001) and oral calcium (P less than 0.001) independently influenced coefficients of absorption for major fatty acids fed (C12:0, C14:0, C16:0, C18:0, and C18:1). Although the main indices for growth were similar in both feeding groups, infants with inefficient rates of total fatty acid absorption attained slower rates of weight gain and increased skinfold thickness. We conclude that oral calcium supplements significantly alter the efficiency of lipid absorption in enterally fed preterm infants.

Trans fatty acids in human milk lipids: influence of maternal diet and weight loss.

Geometric and positional isomers of octadecanoic acid in milk expressed during the first 9 weeks of lactation were determined for mothers delivering prematurely (PT) and at term (FT). Total C18:1 concentration was lower in PT than FT milk. C18:1 trans (elaidic acid) content was higher in PT and FT colostrum compared with subsequent milk samples. No relationship was observed between C18:1 trans level in milk and oleic acid, linoleic acid, total fatty acid levels, or volume of milk expressed. While gestational age and lactational stage appeared to affect the trans fatty acid pattern, the overriding influence was rate of maternal postpartum weight loss. Effect of weight loss on milk trans fatty acid levels was independent of maternal diet. Trans fatty acid content of milk as a function of recent maternal fat intake was also demonstrated. This study indicates that infants receiving human milk ingest levels of trans fatty acids reflecting short and long term maternal diet.