Effect of tasteless calorie-free gum chewing before meal on postprandial plasma glucose, insulin, glucagon, and gastrointestinal hormones in Japanese men without diagnosed glucose metabolism disorder: a pilot randomized crossover trial

This pilot study aimed to examine the effect of pre-meal tasteless calorie-free gum chewing on post-meal blood levels of glucose, insulin, glucagon, and gastrointestinal hormones. This was an open-label, randomized, 2-sequence, 3-period, 2-treatment crossover trial with a 1:1 allocation. Sixteen Japanese adult male volunteers aged between 30 and 49 years without diagnosed glucose metabolism disorder were enrolled. Ingestion of 200-g cooked rice after 15-min tasteless calorie-free gum chewing (GUM+ treatment) was compared to that without preceding gum chewing (GUM− treatment). Cooked rice was divided into twelve equally sized portions and consumed by chewing each portion 30 times before swallowing. Treatment sessions were separated by an at least 1-week interval and attended after an overnight fast. Circulating levels of glucose, insulin, glucagon, active glucagon-like peptide (GLP)-1 and ghrelin were measured at baseline (before treatment) and 0, 15, 30, 60, and 120 min after completion of the meal ingestion, and the postprandial change from baseline was assessed. As a result, the change in glucose levels at 0 min was significantly lower in the GUM+ treatment than in the GUM− treatment (P = 0.004). Furthermore, the GUM+ treatment demonstrated higher incremental insulin levels at 15 min (P = 0.041) and higher incremental active GLP-1 levels at 30 and 60 min (P = 0.018 and 0.021, respectively); whereas, postprandial glucagon and ghrelin levels were not significantly different. In conclusion, the current pilot study demonstrated that tasteless calorie-free gum chewing before rice eating had a significant but limited impact on the increase of postprandial active GLP-1 levels in male individuals without diagnosed glucose metabolism disorder.