Lipid digestion and absorption in early life: an update.
OBJECTIVE
To highlight our understanding of digestion and absorption of dietary lipids in newborn infants, and specifically how these processes differ from those in children and adults.


RESULTS
The intestinal concentration of pancreatic triglyceride lipase (PTL) and bile salts is lower in newborns compared to later in life. Instead the PTL-related protein 2 and bile salt-stimulated lipase (BSSL) are the key enzymes secreted from pancreas, which in concerted action with gastric lipase operate to achieve efficient fat absorption during infancy. BSSL is also present in human milk which affects fat absorption and growth in breast-fed preterm infants. Under conditions of low luminal bile salt concentrations fat absorption is likely to occur from liquid crystalline product phases, which may result in absorption from an extended part of the small intestinal mucosal surfaces compared to adults. Chylomicron assembly and secretion also seem to adapt to the specific situation of the newborn.


CONCLUSIONS
Both fat digestion and product absorption are different in newborn infants compared to adults; other lipases are used for digestion and different physical-chemical phases may be used for product absorption. Why these differences occur is still an unsolved question of considerable importance to neonatal nutrition.
Lindquist
Susanne
S
Department of Clinical Sciences/Pediatrics, Umeå University, Umeå, Sweden. susanne.lindquist@pediatri.umu.se
Hernell
Olle
O
D000328:Adult; D001647:Bile Acids and Salts / Q000378:metabolism*; D001942:Breast Feeding; D002914:Chylomicrons / Q000378:metabolism; D004041:Dietary Fats / Q000378:metabolism*; D004063:Digestion; D006801:Humans; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D007234:Infant, Premature; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*; D050356:Lipid Metabolism; D008895:Milk, Human / Q000737:chemistry; D010179:Pancreas / Q000201:enzymology
D001647:Bile Acids and Salts; D002914:Chylomicrons; D004041:Dietary Fats; C054621:CEL protein, human; D008049:Lipase