Fat Loss in Continuous Enteral Feeding of the Preterm Infant: How Much, What and When Is It Lost?

Human milk fat is a concentrated source of energy and provides essential and long chain polyunsaturated fatty acids. According to previous experiments, human milk fat is partially lost during continuous enteral nutrition. However, these experiments were done over relatively short infusion times, and a complete profile of the lost fatty acids was never measured. Whether this loss happens considering longer infusion times or if some fatty acids are lost more than others remain unknown. Pooled breast milk was infused through a feeding tube by a peristaltic pump over a period of 30 min and 4, 12 and 24 h at 2 mL/h. Adsorbed fat was extracted from the tubes, and the fatty acid composition was analyzed by gas chromatography-mass spectrometry. Total fat loss (average fatty acid loss) after 24 h was 0.6 ± 0.1%. Total fat loss after 24 h infusion was 0.6 ± 0.1% of the total fat infused, although the highest losses occur in the first 30 min of infusion (13.0 ± 1.6%). Short-medium chain (0.7%, p = 0.15), long chain (0.6%, p = 0.56), saturated (0.7%, p = 0.4), monounsaturated (0.5%, p = 0.15), polyunsaturated fatty (0.7%, p = 0.15), linoleic (0.7%, p = 0.25), and docosahexaenoic acids (0.6%, p = 0.56) were not selectively adsorbed to the tube. However, very long chain fatty (0.9%, p = 0.04), alpha-linolenic (1.6%, p = 0.02) and arachidonic acids (1%, p = 0.02) were selectively adsorbed and, therefore, lost in a greater proportion than other fatty acids. In all cases, the magnitude of the loss was clinically low.