Effect of Macronutrient Type and Gastrointestinal Release Site on PYY Response in Normal Healthy Subjects

BACKGROUND AND AIMS

Enteroendocrine L cells release satiety inducing hormones in response to stimulation by luminal macronutrients. We sought to profile the differential effect of macronutrient type and site of release on circulating concentrations of the L cell-derived enteroendocrine hormone peptide tyrosine tyrosine (amino acids 1 to 36) (PYY).

MATERIALS AND METHODS

Eight healthy volunteers were recruited to a randomized, double-blinded, six-way crossover study. At each visit, the participants consumed a 500-kcal drink containing carbohydrate, protein, or fat in either gastric or small intestinal release formulations. Plasma PYY concentrations and hunger ratings were assessed for 3 hours after consumption of the test drink. The food intake was recorded thereafter at an ad libitum lunch.

RESULTS

Microcapsular formulations targeting the distal small intestinal delivery of fat, but not carbohydrate or protein, markedly enhance PYY release relative to macronutrient delivery in gastric release formulations. Food intake at an ad libitum meal was lowest after consumption of the formulation releasing fat at the distal small intestine.

CONCLUSION

Targeting of fat to the distal small intestine in delayed release microcapsules enhanced PYY release and was associated with reductions in food intake.

The Effect of an Encapsulated Nutrient Mixture on Food Intake and Satiety: A Double-Blind Randomized Cross-Over Proof of Concept Study

Activation of the intestinal brake by infusing nutrients into the distal small intestine with catheters inhibits food intake and enhances satiety. Encapsulation of macronutrients, which protects against digestion in the proximal gastrointestinal tract, can be a non-invasive alternative to activate this brake. In this study, we investigate the effect of oral ingestion of an encapsulated casein and sucrose mixture (active) targeting the distal small intestine versus a control product designed to be released in the stomach on food intake, satiety, and plasma glucose concentrations. Fifty-nine volunteers received the active and control product on two separate test days. Food intake was determined during an ad libitum meal 90 min after ingestion of the test product. Visual analogue scale scores for satiety and blood samples for glucose analysis were collected at regular intervals. Ingestion of the active product decreased food intake compared to the control product (655 kcal compared with 699 kcal, respectively, p < 0.05). The area under the curve (AUC) for hunger was decreased (p < 0.05) and AUC for satiety was increased (p < 0.01) after ingestion of the active product compared to the control product. Ingestion of an encapsulated protein-carbohydrate mixture resulted in inhibition of food intake compared to a non-encapsulated control product.