Quantitative and qualitative study of gastric lipolysis in premature infants: do MCT-enriched infant formulas improve fat digestion?

Intragastric fat digestion was investigated by analyzing the products of lipolysis and the gastric lipase (HGL) levels of premature infants fed with a formula enriched with medium chain triglycerides (MCT) and those of infants fed with human milk. Infants were fed using a gastric tube and the gastric contents were aspirated twice a day for 5 d, before and at various times after gavage feeding. HGL levels were measured using the pHstat technique. After extraction, lipids were separated and quantified using thin-layer chromatography coupled to a flame ionization detector. Fatty acid methyl esters were analyzed by gas chromatography. HGL concentration increased during digestion, reaching 77.4 +/- 43.1 microg/mL (around 75% of those recorded in adults). Mean HGL output was 115 +/- 43 microg for 3 h and the overall intragastric lipolysis was 6.1 +/- 2.6%. Although the formula was enriched with octanoic and decanoic acid, the main fatty acids released in the stomach were palmitic (C16:0, 17.03 +/- 0.23% wt/wt) and oleic (C18:1 n-9, 28.23 +/- 1.26% wt/wt) acid. Similar results were obtained with infants fed with human milk. MCT supplementation has no quantitative or qualitative effects on the intragastric lipolysis, which is not higher in premature infant than in adults.