To support rapid growth and a high metabolic rate, infants require enormous amounts of nutrients. The small intestine must have the complete array of transporters that absorb the nutrients released from digested food. Failure of intestinal transporters to function properly often presents symptoms as “failure to thrive” because nutrients are not absorbed and as diarrhea because unabsorbed nutrients upset luminal osmolality or become substrates of intestinal bacteria. We enumerate the nutrients that constitute human milk and various infant milk formulas, explain their importance in neonatal nutrition, then describe for each nutrient the transporter(s) that absorbs it from the intestinal lumen into the enterocyte cytosol and from the cytosol to the portal blood. More than 100 membrane and cytosolic transporters are now thought to facilitate absorption of minerals and vitamins as well as products of digestion of the macronutrients carbohydrates, proteins, and lipids. We highlight research areas that should yield information needed to better understand the important role of these transporters during normal development.
*Institut National de la Recherche Agronomique, UMR1079 Système d'Elevage, Nutrition, Animale et Humaine, St-Gilles, France
†Department of Pediatrics, USA
‡Department of Pharmacology and Physiology, UMDNJ New Jersey Medical School, Newark, NJ, USA.
Received 20 April, 2010
Accepted 9 May, 2010
Address correspondence and reprint requests to Ronaldo P. Ferraris, Department of Pharmacology and Physiology, New Jersey Medical School, MSB-H621, 185 South Orange Ave, Newark, NJ 07103 (e-mail: Ferraris@umdnj.edu).
Drs G. Boudry, E.S. David, V. Douard, and I. Monteiro contributed equally to this work.
The laboratory of Dr Ferraris receives support from the National Science Foundation (IOS 105-0722365) and the NIH (RDK075617A and RAI078518A).
The authors report no conflicts of interest.