Blood glucose levels following starch ingestion are influenced by genetically determined differences in salivary amylase, an enzyme that breaks down dietary starches, according to a new study in the Journal of Nutrition (April 4, 2012) by scientists from the Monell Center.
In the study, amylase activity was measured in saliva samples obtained from 48 healthy adults. Based on extremes of salivary amylase activity, two groups of seven were formed: high amylase (HA) and low amylase (LA).
Each subject drank a simplified corn starch solution and blood samples were obtained over a two-hour period afterwards. The samples were analyzed to determine blood glucose levels and insulin concentrations.
After ingesting the starch, individuals in the HA group had lower blood glucose levels relative to those in the LA group. This appears to be related to an early release of insulin by the HA individuals.
"Not all people are the same in their ability to handle starch," said senior author Paul Breslin, PhD, a sensory geneticist at Monell, in a press release. "People with higher levels of salivary amylase are able to maintain more stable blood glucose levels when consuming starch. This might ultimately lessen their risk for insulin resistance and non-insulin-dependent diabetes."
The findings are the first to demonstrate a significant metabolic role for salivary amylase in starch digestion, suggesting that this oral enzyme may contribute significantly to overall metabolic status.
Additional studies will confirm the current findings using more complex starchy foods, such as bread and pasta, the researchers noted.
