Oral Carbohydrate Sensing

Oral carbohydrate sensing is the detection of carbohydrates by sensory systems in the mouth. It includes the familiar sweet taste of sugars and may also involve responses to some carbohydrates that are not explained by sweetness alone. Sensory detection can occur before carbohydrate is swallowed and absorbed as fuel .^1,2

Sugars activate the sweet taste receptor, which is formed by two proteins called T1R2 and T1R3. However, carbohydrates also include longer chains of sugar units, such as starch and its breakdown products. Research suggests that some of these products can be sensed through additional pathways. These possible pathways should not be treated as a single, fully identified human carbohydrate receptor .¹

One way to investigate oral sensing is to expose the mouth to a carbohydrate solution and then have participants spit it out. This separates mouth exposure from deliberate ingestion. Separate brain imaging experiments have found that oral glucose and maltodextrin can activate regions associated with reward and movement control. These findings support a role for sensory signals from the mouth, although they do not identify the receptors involved .²