LONG CHAIN POLYUNSATURATED FATTY ACIDS AND LIVERBIOCHEMISTRY IN BREAST-FED INFANTS

Abstract

Background: In a previous study we found higher levels of aspartate aminotransferase (AST) among breast-fed (BF) infants compared with formula-fed (FF) infants (1). Albumin was also higher and AST was found to be positively associated with plasma IGF-1. Thus, the elevated level of AST in BF-infants is unlikely to reflect liver injury. Rather it could be explained by induction of hepatocytes by factors in human milk (HM). In the sinusoidal membrane of the hepatocyte AST facilitates uptake of fatty acids into the liver. HM contains docosahexaenoic acid (DHA), whereas formulas supply only the precursor. We investigate if DHA intake is associated with elevated AST in BF infants. Methods: Within two weeks after delivery 60 mothers with an average fish intake below the population median were randomized to daily supplementation during the first 4 mo of lactation with either 4.5 g fish oil (FO) or 4.5 g olive oil (OO), a third group of 41 women with a fish intake within the highest quartile was used as a reference group (HF). DHA in HM was measured at 4 mo as was albumin, AST, alanin aminotransferase (ALT) and gammaglutamyl transferase (GGT). Results: All 101 infants received HM, 77 infants were exclusively breast-fed (BF), 24 infants were supplemented with formula (FS). DHA in human milk was 0.4 wt% (OO), 0.7 wt% (HF) and 1.4 wt% (FO) (2). BF infants had significant higher AST (p = 0.012), ALT (p = 0.012) and GGT (p = 0.013) compared with the FS-infants. 83% BF infants had one or more transaminases above reference level, compared with 60% of the FS-infants (Chi-Square, p = 0.04). Albumin tended to be higher among BF-infants (p = 0.09). No differences were found in transaminases among the 3 feeding groups or between the two randomized groups (FO and OO), neither when all infants were included in the analysis or when only exclusively BF-infants were included. Also no association was observed between transaminases and the content of DHA in HM. Conclusion: BF-infants have an altered liver biochemistry. With the higher albumin levels in BF infants it is more likely with a stimulatory effect on the liver rather than injury. The intake of DHA does not account for the variation in transaminases in exclusively or partially BF infants. However the difference found between total BF and total FF infants has not been investigated in this study.