Factors Determining Optimal Fatty Acid Absorption in Preterm Infants

Abstract

Objectives To quantify absorption coefficients of specific fatty acids in preterm infants as a function of diet, formula (F) or breast milk (BM), and postnatal age; and, to identify the fatty acid structural characteristics that determine optimal fatty acid absorption. Methods Fatty acids from dietary and fecal samples were extracted and quantified by gas chromatography-mass spectroscopy. Fatty acid absorption coefficients (FA-CFAs) were calculated by comparing the total amount of fatty acids supplied by the diet to the amount quantified in the total fecal output over a 3-day period. Results 18 infants (BM=8; F=10) were studied at 2 weeks of age and 20 infants (BM=10; F=10) were studied at 6 weeks of age. FA-CFAs decreased with increasing carbon length in formula-fed infants at 2 and 6 weeks. Results were similar, but less in magnitude in breast milk-fed infants at 2 weeks with no difference at 6 weeks. Conclusions Preterm infants fed formula demonstrated lower FA-CFAs as a function of increasing carbon length. This is consistent with limited pancreatic lipase production and with lipase being present in breast milk but not in formula. The fact that this pattern was seen in BM-fed infants at 2 weeks but not 6 weeks of age suggests that intestinal immaturity may also play a role in impaired fatty acid absorption. These data highlight principles that need to be considered to optimize delivery and absorption of dietary LCPUFAs in preterm infants.

Plasma Free Fatty Acids and their Binding Proteins in Preterm Infants

“…Some authors have indicated that absorption of FFAs is worse in formula-fed babies, while in our study we did not find differences in FFA levels regarding feeding protocol [18]. Martin et al [19] noted that preterm babies did not improve FFAs absorption during the first 2 months of life. In our study, in preterm infants, we reported a decrease in plasma FFA concentrations in the second month of life when compared to the results obtained after birth, independent from feeding protocol, as well as lower than in the control group.…”

“…Just after birth, mobilization of FAs from these stores is observed as an increase in plasma FFA concentrations [19]. Preterm infants with low birth weight had reduced endogenous lipid resources, reflected as a lower plasma FFA concentration, also observed in this study, when compared to full-term babies just after birth [19]. It has been previously shown that preterm infants also had developmental deficiencies in enteral fat digestion and absorption, leading to a malabsorptive state [18].…”

“…Just after birth, mobilization of FAs from these stores is observed as an increase in plasma FFA concentrations [19]. Preterm infants with low birth weight had reduced endogenous lipid resources, reflected as a lower plasma FFA concentration, also observed in this study, when compared to full-term babies just after birth [19].…”

Influence of Human Milk and Parenteral Lipid Emulsions on Serum Fatty Acid Profiles in Extremely Preterm Infants

“…However, other lipid components, such as the triacylglycerol‐, phospholipid‐, and cholesterol ester backbones, make up a minor part of the total fat content . Finally, all FAs were assumed to be fully absorbed, although the true bioavailability in preterm infants is reported to be in the range of 85%–100% depending on FA species . Birth weight was used when normalizing milk and parenteral lipid emulsion intake to mg per kg body weight during the first 2 weeks of life.…”

Absorption of Polyunsaturated Fatty Acid (PUFA) Is Related to IgG Blood Levels of Neonatal Pigs during the First 48 Hours Postpartum

“…Along with essential fatty acids, linoleic acid (LA) and alpha linoleic acid (ALA), as well as omega-6 fatty acids such as arachidonic acid (ARA), PUFAs also contribute to a number of physiological functions, including that of immunomodulation [4,5]. However, PUFAs are poorly digested and thus poorly absorbed in preterm infants due to the immaturity of the gastrointestinal system and (developmental) exocrine pancreatic insufficiency [6][7][8][9].…”