Quantitative fecal carbohydrate excretion in premature infants

Despite relative lactase deficiency and pancreatic insufficiency, premature infants are fed formulas containing 50% lactose plus 50% glucose polymers. We measured total fecal carbohydrate excretion in six healthy 32-wk gestation premature infants who had been fed two 0.784-kcal/g formulas that were similar except for the carbohydrate source (100% lactose vs 50% lactose plus 50% glucose polymers). Using a cross-over design with the first formula randomly assigned, two 72-h balance studies were performed with carmine red, an intermittent external marker, and polyethylene glycol (PEG), a continuous internal marker. Formula and stools were analyzed for total carbohydrate (anthrone method) and PEG. There were no significant differences between the two formula periods for carbohydrate intake, mean daily stool output, or fecal carbohydrate excretion. Mean fecal carbohydrate excretion was less than 0.2 g/d, or less than 1% of carbohydrate intake. Thus, older (32-wk gestation) premature infants fed either 100% lactose or 50% lactose plus 50% glucose polymers have minimal fecal losses of intact carbohydrate.