The addition of locust bean gum but not water delayed the gastric emptying rate of a nutrient semisolid meal in healthy subjects

BACKGROUND Most of the previous studies regarding the effects of gel-forming fibres have considered the gastric emptying of liquid or solid meals after the addition of pectin or guar gum. The influence of locust bean gum, on gastric emptying of nutrient semisolid meals in humans has been less well studied, despite its common occurrence in foods. Using a standardised ultrasound method, this study was aimed at investigating if the gastric emptying in healthy subjects could be influenced by adding locust been gum, a widely used thickening agent, or water directly into a nutrient semisolid test meal. METHODS The viscosity of a basic test meal (300 g rice pudding, 330 kcal) was increased by adding Nestargel (6 g, 2.4 kcal), containing viscous dietary fibres (96.5%) provided as seed flour of locust bean gum, and decreased by adding 100 ml of water. Gastric emptying of these three test meals were evaluated in fifteen healthy non-smoking volunteers, using ultrasound measurements of the gastric antral area to estimate the gastric emptying rate (GER). RESULTS The median value of GER with the basic test meal (rice pudding) was estimated at 63%, (range 47 to 84%), (the first quartile = 61%, the third quartile = 69%). Increasing the viscosity of the rice pudding by adding Nestargel, resulted in significantly lower gastric emptying rates (p < 0.01), median GER 54%, (range 7 to 71%), (the first quartile = 48%, the third quartile = 60%). When the viscosity of the rice pudding was decreased (basic test meal added with water), the difference in median GER 65%, (range 38 to 79%), (the first quartile = 56%, the third quartile = 71%) was not significantly different (p = 0.28) compared to the GER of the basic test meal. CONCLUSIONS We conclude that the addition of locust bean gum to a nutrient semisolid meal has a major impact on gastric emptying by delaying the emptying rate, but that the addition of water to this test meal has no influence on gastric emptying in healthy subjects.