EFFECT OF CARBOHYDRATES ON CALCIUM-ABSORPTION IN PREMATURE-INFANTS

Premature infants are susceptible to diseases related to deficient die tary calcium intake. Studies in adults suggest carbohydrates can enhan ce calcium absorption. However, little is known about how carbohydrate s affect calcium absorption in premature infants due to a lack of dire ct in vivo studies. We adapted the triple lumen perfusion method for u se in premature infants to compare calcium absorption 36 mmol/L (1.44 gn) in the absence and presence of either 70 g/L lactose or glucose po lymers. Ca-44 was added to determine endogenous calcium losses. Fourte en infants were studied (gestational age: 31 +/- 0.4 wk; study weight: 1590 +/- 105 g; mean +/- SEM). Calcium absorption from the glucose po lymer solution was greater than that from the control and lactose solu tions (0.17 +/- 0.05 mu mol . min(-1). cm(-1) versus 0.04 +/- 0.04 and 0.008 +/- 0.045 mu mol . min(-1). cm(-1), respectively). Calcium abso rption correlated positively with water and carbohydrate absorption. T he rate of carbohydrate absorption was greater from the glucose polyme rs than from the lactose solution (0.40 +/- 0.10 mg . min(-1). cm(-1) versus 0.22 +/- 0.06, respectively). Based upon Ca-44 absorption, endo genous calcium loss appeared to account for less than 1% of total calc ium flux. We conclude that glucose polymers, but not lactose, enhance calcium absorption in the premature infant, a fact that may be useful in formula design.