Foods for Appetite Control: can carbohydrates stimulate the ileal brake and enhance satiety? (#46)
The ileal brake is a negative feedback mechanism induced when macronutrients, usually absorbed in the duodenum and jejunum, enter the ileum where they are hypothesised to enhance satiety. Naso-ileal (NI) tube feeding studies have clearly shown that delivery of dietary lipids to the ileum activates the ileal brake. Our aim was to determine whether carbohydrate (CHO) also stimulates the ileal brake and suppresses appetite.
Method: Fourteen lean, healthy, male volunteers participated in a randomised, single blind, 4 treatment cross-over, residential study. Following intubation with a 380 cm multi-lumen NI tube (Day 0), isotonic solutions of glucose or saline were infused into either the ileum or duodenum (Days 1-4). Each morning, NI tube position was confirmed by X-ray before consumption of a standardised 2MJ breakfast (0930h). Treatment infusion commenced at 1130h at a rate of 250 mL/h for 90 min (15g glucose delivered). Energy intake (EI) was measured at an ad libitum lunch provided 30 min after the end of infusion (1330h). Blood samples and visual analogue scale (VAS) ratings of hunger, fullness, other appetite-related sensations and gastrointestinal (GI) discomfort were collected throughout the day.
Ileal infusion of glucose increased ratings of fullness (P<0.05) and decreased EI at the ad libitum lunch (-988 kJ, P<0.05) compared with both saline infusions or the duodenal infusion of glucose, respectively. No other significant treatment effects were observed for other appetite-related sensations or for GI discomfort.
We have demonstrated in humans for the first time that CHO delivered to the ileum can enhance satiety and decrease EI at a subsequent meal.