Influences of mastication and food trituration on gastric motility

Objective: The authors investigated the independent influences of mastication and food trituration on gastric emptying (GE) by comparing GE of identical test foods consumed with fine or coarse chewing or coarse chewing preceded by gum chewing. It was determined that GE tended to be slower in coarse chewing than in fine chewing, and that the delayed GE in coarse chewing could be hastened by prior gum chewing. The results suggested that chewing alone may have increased the gastric motility. The purpose of the current study was to clarify the independent influences of mastication and food trituration on gastric motility by electrogastrography (EGG).

Methods: Cutaneous EGG was recorded for 4 hours after a test meal was consumed (commercially prepared for the elderly with chewing difficulties; 396kcal) by 9 healthy young adult males. It was repeated 3 times per subject by altering the chewing conditions as follows: fine or coarse chewing (subjects chewed each mouthful of food thoroughly or swallowed it without chewing or with chewing for a minimum number of times, respectively) and coarse chewing preceded by gum chewing (10min). EGG power spectra and power products in 3 frequency ranges (low: 0.017–0.040Hz, normal: 0.040–0.060Hz, high: 0.060–0.083Hz) were calculated every 15 minutes and statistically compared with one-way analysis of variance and using Tukey's test afterward.

Results: Meal ingestion increased the power products of the EGG signals in all frequency ranges and all chewing conditions. The cumulative power products in the low-frequency range were significantly greater than those in the normal and high ranges after 90 minutes of coarse chewing (p<0.05), indicating the alteration of gastric motility; this was not observed in other chewing conditions.

Conclusion: Particle size of the digested food had limited influences on gastric motility; decreased chewing itself might have altered gastric motor function after meal.