ABSTRACT
Malnutrition frequently occurs among hospitalized children (19, 23, 24) and is associated with increased rates of morbidity and mortality (3, 5). Because of this hypercatabolic condition, a critically ill patient may undergo a process of acute malnutrition within a few days (7, 27, 34). The nutritional or metabolic support provided in these situations is usually by the parenteral or enteral route, depending on the presence of a functioning digestive tract. When exclusively parenteral feeding is used, prolonged fasting may deprive the intestine of specific nutrients and reduce its function of nutrient processing and absorption for lack of a substrate, with the consequent occurrence of atrophy. Clinical and experimental studies have demonstrated the advantages of the enteral route, which is more physiological, has a lower rate of complications and involves easier administration when compared to the parenteral route. Experimental studies (15, 21) have shown a hypoplastic response of the intestinal mucosa of rats after 3 days of parenteral nutrition when compared to controls submitted to enteral feeding. This response was measured in terms of mucosal weight, villus hypoplasia, DNA protein content, enzyme activity, and pancreatic function. Similar changes detected in clinical studies were rapidly reversed to normal after feeding by the digestive route (13). It is suggested that the mechanism of these alterations may involve the absence of intraluminal amino acids needed for enzyme synthesis rather than the lack of specific substrates inducing enzyme production.(ABSTRACT TRUNCATED AT 250 WORDS)