Suppression of Oral Sweet Taste Sensation with Gymnema sylvestre Affects Postprandial Gastrointestinal Blood Flow and Gastric Emptying in Humans

Abstract

An oral sweet taste sensation (OSTS) exaggerates digestive activation transiently, but whether it has a role after swallowing a meal is not known. Gymnema sylvestre (GS) can inhibit the OSTS in humans. We explored the effect of the OSTS of glucose intake on gastrointestinal blood flow, gastric emptying, blood-glucose, and plasma-insulin responses during the postprandial phase. Eight participants ingested 200 g (50 g × 4 times) of 15% glucose solution containing 100 mg of 13C-sodium acetate after rinsing with 25 mL of 2.5% roasted green tea (control) or 2.5% GS solution. During each protocol, gastrointestinal blood flow and gastric emptying were measured by ultrasonography and 13C-sodium acetate breath test, respectively. Decreased subjective sweet taste intensity was observed in all participants in the GS group. The time to attain a peak value of blood flow in the celiac artery and gastric emptying were delayed in the GS group compared with the control group. At the initial phase after glucose intake, blood-glucose and plasma-insulin responses were lower in the GS group than those for the control group. These results suggest that the OSTS itself has a substantial role in controlling postprandial gastrointestinal activities, which may affect subsequent glycemic metabolism.

Suppression of Oral Sweet Sensations during Consumption of Sweet Food in Humans: Effects on Gastric Emptying Rate, Glycemic Response, Appetite, Food Satisfaction and Desire for Basic Tastes

“…Six healthy males and nine healthy females (mean age 22 ± 3 years; mean height 162 ± 11 cm; mean weight, 56 ± 9 kg; mean body mass index (BMI), 21.2 ± 2.4 kg/m 2 ) were included in the study. To determine the total sample size required in this study, we compared gastric emptying index (i.e., Tmax -calc ) between two groups with or without rinsing GS solution using G*Power software (version 3.1.9.2) [12]. We obtained an effect size of 1.24 for a critical t of 2.365 at α of 0.05 and power (1 − β) of 0.80.…”

“…GS is a plant able to selectively suppress the sweet taste sensation in humans [24,25]. We found that GS-dependent suppression of OSS during ingestion of pure glucose solution slowed gastric emptying rate and glycemic response [12,13]. However, it is unknown whether suppressing OSS during consumption of a real sweet food affects both sweet taste liking and CPRs.…”

“…When oral sweet receptor activation is suppressed during eating sweet-tasting food, gastric emptying may be delayed. This is because we have actually found that suppression of OSS during ingestion of glucose has a role in decreasing the gastric emptying and slowing blood glucose (BG) and insulin responses [12,13]. Therefore, to elucidate the role of suppression of OSS in decreased sweet-tasting food consumption, we should examine various physiological responses both during and after the prandial phase of consuming a uniform meal in a laboratory-based basic science approach.…”

Timing of Nutrient Ingestion after Mild to Moderate Cycling Exercise Does Not Affect Gastric Emptying Rate in Humans

“…The Doppler beam insonation angle was maintained at ≤60 • relative to the artery. A previously established methodology [3,7] was used to calculate the second-by-second MBV. First, the Doppler signals for antegrade and retrograde flows and the electrocardiogram signal were digitally sampled online at 20 kHz using an analog/digital converter (PowerLab 8/30, ADInstruments, Colorado Springs, CO, USA).…”

“…The celiac artery supplies blood to the stomach, pancreas, spleen, and liver, and the superior mesenteric artery primarily supplies blood to the jejunum and ileum [6]. Celiac artery BF and superior mesenteric artery BF both increase remarkably after macronutrient food consumption [7,8], and these responses support the various functions of the GI system (e.g., the motility and delivery of absorbed nutrients and the secretion of gut hormones) [6]. Thus, these previous results suggested that post-exercise GI hypoperfusion leads to acutely suppressing subsequent digestive and/or absorptive functions.…”