Slowly Digestible Carbohydrates and the Ileal Brake

Diets containing slowly digestible carbohydrates (SDCs), in the form of starch-entrapped microspheres that digest into the ileum, were previously shown to reduce food intake in a diet-induced obese rat model by activating the gut-brain axis. These results suggested that SDCs trigger the ileal brake, which is a feedback mechanism controlling stomach-mediated transit of a meal. The ileal brake is characterized by delayed gastric emptying rate and increased satiety. The goal of this work was to determine if common SDCs trigger the ileal brake in humans, using gastric emptying rate as a proxy indicator. In a human study, SDCs were delivered through a semi-solid yogurt matrix, and gastric half-emptying time and postprandial glycemic response were assessed. The study was a five-arm, double-blind, crossover design with a one-week washout period between treatments (n=20, 9 females, 11 males). Four different carbohydrate ingredients (SDCs: isomalto-oligosaccharides (IMO), Xtend® sucromalt, and raw corn starch; and non-SDC: maltodextrin) were incorporated individually, or in combination, into yogurt products matched in energy density and viscosity. Participants consumed 300 g test meals of yogurt formulated with one or a combination of the carbohydrate ingredients after an overnight fast. Gastric emptying rates and glycemic response were measured using a 13C-labeled octanoic acid breath test and continuous glucose monitors, respectively. Glucose readings were continuously monitored 24 h prior to and 48 h after test meal consumption, and breath samples were collected for a 4 h period following test meal consumption.

Inclusion criteria

• BMI 18.5 - 25 kg/m2
• Stable weight for the past 3 months (i.e. +/- 2..5 kg)
• Regular eating patterns, including breakfast consumption

Exclusion criteria

• Gastrointestinal disease
• Smokers
• Peri- or post-menopausal women
• Celiac disease (yogurts may contain ingredients with wheat origin)
• Allergies, including dairy, lactose, and gluten
• Pregnant and lactating women
• Following a weight reduction program or having followed one during the last 3 months
• Acute or chronic disease
• Alcohol consumption > 30 units/week
• Hypertension
• Diabetes
• Previous bariatric surgery