Enhancement of calcium absorption in rats by coadministration of glucose polymer

Glucose polymer derived from corn starch is widely used in infant formula and nutritional supplements as a readily digestible, low osmolarity source of calories. We have previously observed that glucose polymer causes a marked increase in intestinal calcium absorption in patients with intestinal malabsorption and in normal subjects. The present study investigates the effect of concurrently administered glucose polymer on intestinal 45calcium absorption in rats. The effect of glucose polymer on calcium absorption was compared to that of equivalent doses of dextrose or lactose. Femur radioactivity was determined as an index of calcium absorption. Carbohydrates were prepared at doses of 0.5, 2.0 and 4.0 mg/g body weight and administered with 45Ca by stomach gavage. Control rats received 45Ca in water alone. Coadministration of glucose polymer resulted in a dose-dependent increase in calcium absorption. At the highest dose of polymer studied calcium absorption was 75% greater than in control animals. Administration of lactose and dextrose also resulted in a dose-dependent increase in calcium absorption. Calcium absorption was 122 and 67% greater than controls when 4 mg/g BW lactose and dextrose were given with the 45Ca. We conclude that glucose polymer stimulates calcium absorption in rats similar to lactose and glucose. These results suggest that glucose polymer may be a useful therapeutic adjunct in patient groups in which there is a desire to increase intestinal calcium absorption.