ecently researchers1 have found an interesting association between salivary amylase and the glycaemic response to starch. Non-obese subjects had their salivary amylase activity assessed by comparison to the mean. They then grouped the subjects as high producers (1 standard deviation above the mean) or low producers (1 standard deviation below the mean). Subjects were then fed a test meal comprising of corn starch hydrolysate or glucose in order to assess their glycaemic response to carbohydrate foods. Following the starch ingestion, high amylase producers had significantly lower blood glucose concentrations at 45, 60, and 75 min, as well as significantly lower area under the curve and peak blood glucose concentrations, when compared to low amylase producers. However, ingestion of glucose did not result in significant differences in blood sugar or insulin levels, suggesting that insulin resistance was not the cause of the different glycaemic effects following starch ingestion.
These results suggest that some individuals produce higher amounts of amylase that decreases the blood sugar concentrations following a test meal of starch. This is interesting because it might be expected that increased amylase activity might increase the speed of digestion and thus cause a significantly larger rise in plasma glucose levels. However the opposite was found. This might be explained by the fact that the high amylase producers may have an increased cephalic phase of digestion. The cephalic phase is the anticipatory phase of digestion that results in salivation at the sight, smell or thought of food. A sensitised cephalic phase could increase cephalic phase insulin release and salivary amylase production. In fact, when the researchers measured the insulin levels of the participants they found higher pre-meal insulin levels in the high amylase group, suggesting that this may indeed be the case.
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