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ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #182602
Title: INFLUENCE OF CHANGES IN LACTASE ACTIVITY AND SMALL-INTESTINAL MUCOSAL GROWTH ON LACTOSE DIGESTION AND ABSORPTION IN PRETERM INFANTS

Author
item Shulman, Robert
item Wong, William
item Smith, O'Brian

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2004
Publication Date: 2/1/2005
Citation: Shulman, R., Wong, W.W., Smith, O.E. 2005. Influence of changes in lactase activity and small-intestinal mucosal growth on lactose digestion and absorption in preterm infants. American Journal of Clinical Nutrition. 81:472-479.

Interpretive Summary: In preterm infants, maturational changes in lactose digestion and absorption appear to be related more to changes in lactase specific activity than to changes in small intestinal mucosal surface area. Lactase specific activity increases out of proportion to that which can be explained solely by changes in small intestinal mucosal growth. Lactase specific activity is related to the maturational state of the infant and to some degree to enteral feeding. In contrast, small intestinal mucosal surface area is related primarily to enteral feeding.

Technical Abstract: Feeding intolerance (i.e., achieving and maintaining full enteral feedings) is a significant problem in preterm infants. A relation exists between feeding intolerance and incomplete lactose digestion. We sought to identify the factors relating to lactose digestion and absorption, lactase activity, and small intestinal mucosal growth. 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 (mean +/- SEM gestational age: 28.0 +/- 0.2 wk). 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). 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 related primarily to lactase activity rather than to mucosal growth. We showed directly a relation between enteral feeding and small-intestinal mucosal growth.