Impairment of starch absorption by a potent amylase inhibitor

Many previous investigations of available amylase inhibitors have not been able to demonstrate significant carbohydrate malabsorption. This study uses breath hydrogen analysis, a sensitive method for detecting the passage of starch into the colon, to determine if a potent amylase inhibitor is capable of producing carbohydrate malabsorption. Thirteen volunteers underwent three studies, ingesting as a carbohydrate substrate: lactulose 20 g, spaghetti alone, and spaghetti with amylase inhibitor (3.8 g). Samples of breath were collected (at frequent intervals) for 2 h after the lactulose and for 8 h after the spaghetti meal and analyzed for hydrogen concentration. The ingestion of spaghetti alone resulted in significant increases in breath hydrogen concentration at 420-450 min. The mean (+/- SE) hydrogen excretion rate was increased more than 2-fold with the amylase inhibitor, from 0.4 +/- 0.2 to 0.9 +/- 0.3 ml/h (p less than 0.05). Use of the amylase inhibitor in powder form produced a similar increase in the rate of hydrogen excretion to 1.1 +/- 0.4 ml/h. The percentage of carbohydrate malabsorbed was calculated for the spaghetti meal and spaghetti with amylase inhibitor using each individual's observed hydrogen excretion with lactulose. Over the 8-h observation period, 4.7 +/- 1.9% of the spaghetti was malabsorbed and 7.0 +/- 1.4% of the spaghetti with amylase inhibitor was malabsorbed (p less than 0.05). Measurements of the effect of the amylase inhibitor on amylase activity of duodenal juice revealed that the amylase inhibitor at a concentration of more than 5 mg/ml decreased the amylase activity by more than 96%. These results indicate that this potent amylase inhibitor is capable of enhancing malabsorption of wheat starch.