Ileal glucose infusion suppresses appetite, reduces ad libitum energy intake
The outcomes are different with the delivery of macronutrient to the proximal and distal small intestine, a recent study has found.
Glucose infusion to the ileum increases glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) secretion, suppresses aspects of visual analogue scale (VAS)-rated appetite, and lowers ad libitum energy intake at a subsequent meal. Glucose infusion to the duodenum also suppresses appetite ratings, but the eating behaviour has not changed.
Researchers randomized 14 healthy male participants to a blinded four-treatment crossover, with each treatment of single-day duration, to investigate whether glucose infused into the duodenum and ileum differentially altered appetite response, food intake and secretion of satiety-related gastrointestinal peptides.
A day prior to the intervention (day 0), a 380-cm multilumen tube (1.75-mm diameter) with independent port access to the duodenum and ileum was inserted. Its position was confirmed by X-ray. In the following days (days 1 to 4), isotonic glucose (15 g, 235 kJ) or saline was infused for 90 minutes to the duodenum or ileum after a standardized breakfast meal.
VASs, blood samples collected and ad libitum energy intake measured at lunch, afternoon snack and dinner were used to evaluate appetite ratings.
In total, 13 participants completed the 4 days of infusion. A significant effect of nutrient infused and site (treatment x time, p<0.05) was observed.
Glucose-to-ileum changed VAS-rated fullness, satisfaction and thoughts of food compared with saline-to-ileum (Tukey’s post hoc; p<0.05); reduced ad libitum energy intake at lunch compared with glucose-to-duodenum (‒22 percent; mean ‒988 kJ; Tukey’s post hoc, p<0.05); and increased GLP-1 and PYY versus all other treatments (Tukey’s post hoc, p<0.05).
“Activation of the ileal brake through the delivery of nutrients into the distal small intestine to promote satiety and suppress food intake provides a new target for weight loss,” according to researchers.