Gastric Lipolysis and Fat Absorption in Preterm Infants: Effect of Medium-Chain Triglyceride or Long-Chain Triglyceride-Containing Formulas

Abstract

The extent of gastric lipolysis, fat absorption, and infant weight gain was studied in 12 preterm infants (gestational age 28.75 ± 0.50 weeks, postnatal age 6.08 ± 0.81 weeks) fed medium-chain triglyceride or long-chain triglyceride formula for 1 week in a crossover design. The former formula contained 42% of 8:0 and 10:0 and 19% of 12:0, 14:0, and 16:0; the latter formula contained only 7% of 8:0 and 10:0 and 46% of 12:0, 14:0, and 16:0. Gastric aspirates were obtained on the second and third day of formula feeding for quantitation of lipase activity and of the extent of gastric lipolysis. Fat balance studies were conducted during the last three days of each feeding regimen. The study showed that (1) there was marked hydrolysis of formula fat in the stomach during feeding of either medium-chain triglyceride formula or long-chain triglyceride formula (20% and 16%, respectively); (2) lipase activity in the gastric aspirates was less during feeding of medium-chain triglyceride formula than before the meal, which suggested stimulation of lipase secretion by long-chain fatty acid released from long-chain triglyceride formula fat or more rapid binding of lipase to ingested lipid in the medium-chain triglyceride formula; (3) fatty acid distribution in glycerides and free fatty acids showed preferential release of medium-chain (8:0, 10:0) and long-chain unsaturated (18:1, 18:2) fatty acids in the stomach. The low content of 8:0 and 10:0 in gastric triglyceride and free fatty acids suggested that medium-chain fatty acids were absorbed directly in the stomach. (4) fat balance studies showed almost identical absorption rates (84.6% ± 3.1% and 82.8% ± 4.0%) and weight gain (23.0 ± 1.5 g/d and 20.8 ± 1.8 g/d) during feeding of either medium-chain triglyceride or long-chain triglyceride formula. In this study, in which each infant was fed either formula alternately, it was shown that although the extent of fat digestion varied among infants, medium-chain and long-chain triglyceride were absorbed to the same extent by most infants.

Triacylglycerol Containing Medium-Chain Fatty Acids: Comparison of Human Milk and Infant Formulas on Lipolysis during In Vitro Digestion

“…27 Nevertheless, Hamosh et al reported there was marked hydrolysis of formula fat in the stomach during feeding with either MCT formula (42% of 8:0−10:0) or LCT formula (7% of 8:0−10:0), which was 20 and 16%, respectively. 9 Of note, the proportion of TAG in IF 4 during gastric digestion (Figure S1) was relatively high despite its higher lipolysis degree, indicating that the TAGs in human milk were hydrolyzed more easily than those in IFs.…”

“…The preferential release of MCFAs (8:0 and 10:0) by gastric lipase has been demonstrated in one in vivo study on gastric lipolysis in preterm infants fed the MCT or LCT formula. 9 A previous study on in vitro digestion demonstrated that RGL was highly specific toward the hydrolysis of MCFAs during the digestion of IFs (MCT-IF and LCT-IF), particularly when the MCT-IF was used as a substrate. RGL released only 8:0 and 10:0 under gastric conditions, while ROL digested FAs of all lengths relative to their initial composition in human milk and seemed to be insensitive to the FA chain length.…”

Role Medium-Chain Fatty Acids in the Lipid Metabolism of Infants

“…It has been shown that the gastric hydrolysis of fat is higher in infants fed with human milk than those fed with a formula, including the MCT formula, although the 8:0 and 10:0 were less abundant in human milk (approximately 2%) than those in an infant formula (approximately 24%) ( 42 , 43 ). Moreover, a crossover study showed that MCFAs in the MCT formula (42% MCT) and the LCT formula (7% MCT) fed to 12 preterm infants were hydrolyzed to the same extent ( 44 ), suggesting that MCT supplementation has no improvement on gastric lipolysis, possibly because of the stimulation of lipase secretion by LCFAs ( 44 , 45 ). Still, short-chain FAs and MCFAs could be absorbed directly through the stomach wall and enter the portal vein, so even MCT molecules could be partially absorbed ( 44 , 46 ), which provides infants with a readily available energy source.…”

“…Moreover, a crossover study showed that MCFAs in the MCT formula (42% MCT) and the LCT formula (7% MCT) fed to 12 preterm infants were hydrolyzed to the same extent ( 44 ), suggesting that MCT supplementation has no improvement on gastric lipolysis, possibly because of the stimulation of lipase secretion by LCFAs ( 44 , 45 ). Still, short-chain FAs and MCFAs could be absorbed directly through the stomach wall and enter the portal vein, so even MCT molecules could be partially absorbed ( 44 , 46 ), which provides infants with a readily available energy source.…”

The Role of Dietary Fats in the Development and Prevention of Necrotizing Enterocolitis

“…Each lipase has a specific affinity and function that is largely based on the site of secretion. Although lingual and gastric lipases account for up to 30% of lipid digestion in orally fed preterm infants, most fat digestion relies on pancreatic and salt-stimulated lipases [ 50 , 51 , 52 , 53 , 54 ]. Studies indicate that preterm infants are deficient in pancreatic lipases, particularly the bile salt-dependent lipase [ 33 , 55 , 56 ].…”