The effect of submicron fat droplets in a drink on satiety, food intake, and cholecystokinin in healthy volunteers.

PURPOSE: Small fat droplets infused into the gut reduce food intake and hunger more than bigger ones, at levels as low as 6 g, and these effects are hypothesized to occur via satiety hormones such as cholecystokinin. It is, however, unknown whether the effect of droplet size would persist after oral consumption. It is also unknown whether an even smaller droplet size can affect hunger and food intake and at what minimum amount of fat. Therefore, the aim of the study was to test the effect of very fine fat droplets on satiety and food intake in two different quantities. METHODS: In a balanced-order 4-way crossover design, 24 volunteers consumed a fat-free meal replacement drink with either 5 or 9 g oil (rapeseed) and either 3 or 0.1 µm droplet size. Appetite scores and plasma cholecystokinin levels (in n = 12 subset) were measured for 180 min, when food intake was assessed during an ad libitum meal. Data were analyzed by ANCOVA, followed by Dunnett's test and paired t test. The behavior of the emulsions was also characterized in a simulated gastrointestinal model. RESULTS: Despite faster in vitro lipolysis of the smallest droplets, neither droplet size nor fat amount affected satiety or food intake. From t = 45-150 min, cholecystokinin response was 50% higher (P < 0.05) after the 0.1 versus 3 µm, but only with 9 g fat. CONCLUSION: When this particular fat at these amounts is delivered in a meal replacement drink, droplet size does not influence appetite or food intake. This effect is independent of the amount of fat or plasma cholecystokinin changes.

Length and site of the small intestine exposed to fat influences hunger and food intake.

The site of intestinal fat delivery affects satiety and may affect food intake in humans. Animal data suggest that the length of the small intestine exposed to fat is also relevant. The aim of the present study was to investigate whether increasing the areas of intestinal fat exposure and the way it is exposed would affect satiety parameters and food intake. In the present single-blind, randomised, cross-over study, fifteen volunteers, each intubated with a naso-ileal tube, received four treatments on consecutive days. The oral control (control treatment) was a liquid meal (LM) containing 6 g fat ingested at t = 0 min, with saline infusion at t = 30-120 min. Experimental treatments were a fat-free LM at t = 0 min, with either 6 g oil delivered sequentially (2 g duodenal, t = 30-60 min; 2 g jejunal, t = 60-90 min; 2 g ileal, t = 90-120 min), simultaneously (2 g each to all sites, t = 30-120 min) or ileal only (6 g ileal, t = 30-120 min). Satiety parameters (hunger and fullness) and cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), peptide YY (PYY) secretion were measured until t = 180 min, when ad libitum food intake was assessed. Only the ileum treatment reduced food intake significantly over the control treatment. The ileum and simultaneous treatments significantly reduced hunger compared with the control treatment. Compared with control, no differences were observed for PYY, CCK and GLP-1 with regard to 180 min integrated secretion. Ileal fat infusion had the most pronounced effect on food intake and satiety. Increasing the areas of intestinal fat exposure only affected hunger when fat was delivered simultaneously, not sequentially, to the exposed areas. These results demonstrate that ileal brake activation offers an interesting target for the regulation of ingestive behaviour.

The effect of lipid droplet size on satiety and peptide secretion is intestinal site-specific.

BACKGROUND & AIMS: : Infusion of fat into the small intestine induces satiety. Reducing fat droplet size accelerates fat digestion, but the effect on satiety after ileal fat infusion is not known. The aim of the study was to compare the effects of fat emulsions differing in droplet size (fine, coarse) infused in either duodenum or ileum on satiety, gastric emptying and peptide secretion. METHODS: In a randomized single-blind crossover study 15 healthy volunteers received, after intubation with a nasoileal tube, 4 different treatments on 4 consecutive days. After consumption of a liquid meal, 6 g of fine or coarse fat emulsion was infused into duodenum or ileum. Study parameters were satiety, gastric emptying and gut peptides. These parameters were statistically evaluated using ANCOVA. RESULTS: In the duodenum, Fine emulsion significantly reduced hunger, increased fullness, delayed gastric emptying, but did not affect peptide secretion versus Coarse. In the ileum, Fine emulsion did not affect hunger, fullness, or gastric emptying, but significantly increased peptide secretion versus Coarse. CONCLUSIONS: Compared to larger fat droplets, smaller droplets significantly affect satiety, gastric emptying and gut peptide release, but with the effect being dependent on the intestinal location of fat delivery. DUTCH TRIALREGISTER: NTR1515.

Dose-dependent suppression of hunger by a specific alginate in a low-viscosity drink formulation.

Addition of specific types of alginates to drinks can enhance postmeal suppression of hunger, by forming strong gastric gels in the presence of calcium. However, some recent studies have not demonstrated an effect of alginate/calcium on appetite, perhaps because the selected alginates do not produce sufficiently strong gels or because the alginates were not sufficiently hydrated when consumed. Therefore, the objective of the study was to test effects on appetite of a strongly gelling and fully hydrated alginate in an acceptable, low-viscosity drink formulation. In a balanced order crossover design, 23 volunteers consumed a meal replacement drink containing protein and calcium and either 0 (control), 0.6, or 0.8% of a specific high-guluronate alginate. Appetite (six self-report scales) was measured for 5 h postconsumption. Relevant physicochemical properties of the drinks were measured, i.e., product viscosity and strength of gel formed under simulated gastric conditions. Hunger was robustly reduced (20-30% lower area under the curve) with 0.8% alginate (P < 0.001, analysis of covariance), an effect consistent across all appetite scales. Most effects were also significant with 0.6% alginate, and a clear dose-response observed. Gastric gel strength was 1.8 and 3.8 N for the 0.6 and 0.8% alginate drinks, respectively, while product viscosity was acceptable (<0.5 Pa.s at 10 s(-1)). We conclude that strongly gastric-gelling alginates at relatively low concentrations in a low-viscosity drink formulation produced a robust reduction in hunger responses. This and other related studies indicate that the specific alginate source and product matrix critically impacts upon apparent efficacy.

Effect of fat saturation on satiety, hormone release, and food intake.

BACKGROUND: Ileal delivery of fat reduces hunger and food intake through activation of the ileal brake. Physicochemical properties of fat have been shown to affect satiety and food intake. OBJECTIVE: The objective of this study was to assess the effect of ileal fat emulsions with differing degrees of fatty acid saturation on satiety, food intake, and gut peptides (cholecystokinin and peptide YY). We hypothesized that long-chain triacylglycerols with diunsaturated fatty acids would increase satiety and reduce energy intake compared with long-chain triacylglycerols with monounsaturated or saturated fatty acids. DESIGN: We performed a double-blind, randomized, crossover study in which 15 healthy subjects [mean age: 24 y; mean body mass index (in kg/m(2)): 22] were intubated with a naso-ileal catheter and participated in 4 experiments performed in random order on 4 consecutive days. After consumption of a liquid meal, subjects received a fat or control infusion in the ileum. Fat emulsions consisted of 6 g of 18:0 (shea oil; mainly 18:0), 18:1 (canola oil; mainly 18:1), or 18:2 (safflower oil; mainly 18:2) oils. Food intake was measured during an ad libitum lunch. Satiety questionnaires (visual analog scale) and blood samples were collected at regular intervals. RESULTS: Compared with the control, only 18:2 and 18:1 significantly increased fullness and reduced hunger. No effect on food intake was observed. 18:1 and 18:2 increased cholecystokinin secretion significantly compared with the control. Fatty acid saturation did not affect peptide YY secretion. CONCLUSIONS: When infused into the ileum, triacylglycerols with unsaturated fatty acids increase satiety, whereas triacylglycerols with saturated fatty acids does not. This trial was registered with the Dutch Trial Register as: ISRCTN51742545.

No effect of added beta-glucan or of fructooligosaccharide on appetite or energy intake.

BACKGROUND: An increase in gastrointestinal viscosity or colonic fermentation is suggested to improve appetite control and reduce food intake. It has been proposed that beta-glucan and fructooligosaccharide (FOS) are food ingredients that increase gastrointestinal viscosity and colonic fermentation, but the results are inconclusive. OBJECTIVE: The objective was to test the effect of FOS, beta-glucan, or a combination thereof on appetite ratings and food intake over 2 consecutive days. DESIGN: In a 4-way balanced-order, crossover, double-blind design, 21 healthy volunteers [mean body mass index (in kg/m(2)) 25.9] consumed a meal-replacement bar at 0900 and an ad libitum lunch at 1300 on 2 consecutive days. On day 1 only, the subjects consumed a second (identical) bar at 1700 and a fixed snack at 1900. The control bar contained 0.3 g beta-glucan from 6.8 g oats (control), and the 3 equicaloric test bars contained an additional 0.9 g beta-glucan (from 8.0 g barley), 8 g FOS, or 0.9 g beta-glucan + 8 g FOS. Appetite scores and subsequent ad libitum test meal intakes were measured. Viscosities in response to bar consumption were determined under simulated gastric conditions. The results were analyzed by analysis of covariance. RESULTS: The addition of beta-glucan, FOS, or a combination thereof did not affect appetite ratings or food intake, although the addition of beta-glucan to the bar doubled gastric viscosity (841 compared with 351 mPa . s). CONCLUSIONS: Consumption of beta-glucan, FOS, or a combination thereof in meal-replacement bars at the levels tested for 2 consecutive days does not improve appetite control. Efficacy may have improved if the consumption period was longer, if the content of beta-glucan was greater, or if a form of beta-glucan that generates even higher gastric viscosity was consumed. This trial was registered at (clinicaltrials.gov) as NCT00776256.