Influence of changes in lactase activity and small-intestinal mucosal growth on lactose digestion and absorption in preterm infants.
BACKGROUND
Feeding intolerance (ie, achieving and maintaining full enteral feedings) is a significant problem in preterm infants. A relation exists between feeding intolerance and incomplete lactose digestion.


OBJECTIVE
We sought to identify the factors relating to lactose digestion and absorption, lactase activity, and small-intestinal mucosal growth.


METHODS
Lactose digestion and absorption, lactase-specific activity, and lumen-to-mucosa water flux as a measure of small-intestinal mucosal surface area were determined by using the triple-lumen perfusion technique on 2 occasions 3 wk apart in 10 preterm infants (x+/-SEM gestational age: 28.0+/-0.2 wk).


RESULTS
Lactose digestion and absorption and lactase activity doubled between studies (P=0.035 and P=0.041, respectively). The change in digestion and absorption was related to lactase activity (P=0.034, R2=0.38). Lactase activity correlated with gestational age at birth (P=0.012, R2=0.51). The number of days of feeding explained 80% of the variability in small-intestinal mucosal surface area (P=0.001).


CONCLUSIONS
To our knowledge, this is the first study to measure directly lactose digestion and absorption, lactase activity, and small-intestinal surface area in preterm infants. Changes in lactose absorption relate primarily to lactase activity rather than to mucosal growth. We showed directly a relation between enteral feeding and small-intestinal mucosal growth.
Shulman
Robert J
RJ
Department of Pediatrics, Baylor College of Medicine, US Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Texas Children's Hospital, Houston, TX 77030, USA. rshulman@bcm.tmc.edu
Wong
William W
WW
Smith
E O'Brian
EO
D004063:Digestion; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000254:growth & development / Q000378:metabolism*; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000201:enzymology* / Q000254:growth & development*; D007421:Intestine, Small / Q000201:enzymology / Q000254:growth & development; D043322:Lactase / Q000172:deficiency / Q000378:metabolism*; D007785:Lactose / Q000493:pharmacokinetics*; D007787:Lactose Intolerance; D010477:Perfusion; D011446:Prospective Studies
D043322:Lactase; D007785:Lactose