Chewing gum after a meal is a common habit, often adopted in the belief that the repetitive motion or flavor will aid digestion. This practice influences the digestive tract through physiological responses starting in the mouth and extending to the stomach. Whether this habit provides a genuine digestive benefit or introduces potential drawbacks depends on the specific mechanisms it triggers.
How Chewing Gum Increases Salivary Flow
The mechanical act of chewing stimulates the salivary glands, significantly increasing saliva production that is sustained as long as the gum is chewed. This flow rate can be up to ten times higher than the resting rate, amplified by the gum’s flavorings. Stimulated saliva aids the initial stage of digestion by lubricating food residue in the mouth.
Saliva contains salivary amylase, an enzyme that begins breaking down complex carbohydrates, such as starches, into simpler sugars. This preliminary action contributes to digestive efficiency, and the continuous production of saliva also aids in the physical clearance of food particles.
Enhancing Esophageal and Stomach Function
The chewing action prepares the digestive tract for a meal through the cephalic phase response, even when no food is swallowed. The increased volume of saliva produced is swallowed, benefiting the lower digestive organs. This stimulated saliva is more alkaline due to a higher concentration of bicarbonate ions.
When swallowed, this alkaline fluid acts as a natural buffer, helping to neutralize stomach acid. This mechanism is beneficial for individuals prone to gastroesophageal reflux disease (GERD) or heartburn.
The frequent swallowing also provides a physical cleansing action, washing refluxed stomach acid back down and away from the esophageal lining. Studies show that chewing sugar-free gum for about 30 minutes after a meal can significantly reduce the time the esophagus is exposed to acid, helping manage post-meal acid discomfort.
Potential Adverse Digestive Effects
While chewing gum offers benefits, the practice is not without potential drawbacks for the digestive system. One common side effect is aerophagia, which is the act of swallowing excess air while chewing. This ingested air accumulates in the gastrointestinal tract, leading to symptoms like bloating, abdominal distension, and increased belching.
Furthermore, many sugar-free gums contain sugar alcohols, such as sorbitol and xylitol, used as sweeteners. These compounds are poorly absorbed in the small intestine because the body lacks the necessary enzymes to break them down effectively. When they reach the large intestine, gut bacteria ferment these sugar alcohols, producing gas as a byproduct, which exacerbates bloating and flatulence. In higher quantities, the unabsorbed sugar alcohols draw water into the colon through an osmotic effect, which can lead to a laxative effect and cause diarrhea.