Normally, there is little reflux of pancreatic juice into the stomach. If reflux does occur, pancreatic amylase along with the swallowed salivary amylase is quickly inactivated by the normal acidity of the stomach. Consequently, digestion of starch, dependent on amylase activity, does not occur in the stomach. Only peptic digestion of protein goes on in this acid media. In the achlorhydric stomach, amylase activity may be significantly greater, especially when the pyloric sphincter mechanism has been destroyed or bypassed. In this situation, pancreatic or salivary amylase may act prematurely with rapid breakdown of the large starch molecule into many smaller carbohydrate molecules and consequent rise in osmolarity. Moore1 has stressed the importance of the stomach as an "osmotic shield" in the prevention of dumping. In the partially resected stomach this shield is lost, for its important function as a food reservoir is vitally impaired and the "installment emptying" characteristic
WELCH HF, ATTARIAN E. Intragastric Amylase Activity and Dumping Syndrome. Arch Surg. 1964;89(1):203–208. doi:10.1001/archsurg.1964.01320010205022
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