Fat emulsion intragastric stability and droplet size modulate gastrointestinal responses and subsequent food intake in young adults

Abstract

Background: Intragastric creaming and droplet size of fat emulsions may affect intragastric behavior and gastrointestinal and satiety responses.

Objectives: We tested the hypotheses that gastrointestinal physiologic responses and satiety will be increased by an increase in intragastric stability and by a decrease in fat droplet size of a fat emulsion.

Methods: This was a double-blind, randomized crossover study in 11 healthy persons [8 men and 3 women, aged 24 ± 1 y; body mass index (in kg/m(2)): 24.4 ± 0.9] who consumed meals containing 300-g 20% oil and water emulsion (2220 kJ) with 1) larger, 6-μm mean droplet size (Coarse treatment) expected to cream in the stomach; 2) larger, 6-μm mean droplet size with 0.5% locust bean gum (LBG; Coarse+LBG treatment) to prevent creaming; or 3) smaller, 0.4-μm mean droplet size with LBG (Fine+LBG treatment). The participants were imaged hourly by using MRI and food intake was assessed by using a meal that participants consumed ad libitum.

Results: The Coarse+LBG treatment (preventing creaming in the stomach) slowed gastric emptying, resulting in 12% higher gastric volume over time (P < 0.001), increased small bowel water content (SBWC) by 11% (P < 0.01), slowed appearance of the (13)C label in the breath by 17% (P < 0.01), and reduced food intake by 9% (P < 0.05) compared with the Coarse treatment. The Fine+LBG treatment (smaller droplet size) slowed gastric emptying, resulting in 18% higher gastric volume (P < 0.001), increased SBWC content by 15% (P < 0.01), and significantly reduced food intake by 11% (P < 0.05, equivalent to an average of 411 kJ less energy consumed) compared with the Coarse+LBG treatment. These high-fat meals stimulated substantial increases in SBWC, which increased to a peak at 4 h at 568 mL (range: 150-854 mL; P < 0.01) for the Fine+LBG treatment.

Conclusion: Manipulating intragastric stability and fat emulsion droplet size can influence human gastrointestinal physiology and food intake.

Keywords: food intake; lipid; magnetic resonance imaging; physical form of food; small bowel; stomach.

FIGURE 1

Schematic diagram of the predicted behavior in the stomach of the 3 meals containing 20% sunflower oil in water emulsions: Coarse, Coarse+LBG, and Fine+LBG. The black dots represent the fat droplets, which are small for the Fine emulsion and large for the Coarse and Coarse+LBG emulsions. The arrows indicate the predicted different appearance of the treatments in the stomach when changing intragastric stability and droplet size of the emulsions. Coarse, 20% oil and water emulsion with 6-μm mean droplet size; Coarse+LBG, 20% oil and water emulsion with 6-μm mean droplet size and 0.5% locust bean gum; Fine+LBG, 20% oil and water emulsion with 0.4-μm mean droplet size and 0.5% locust bean gum; LBG, locust bean gum.

FIGURE 2

The upper part of the panel shows typical balanced turbo field echo (water) images taken across the stomach of the same healthy young adult at time t = 2 h after consumption of each of the 3 test meals containing a 20% sunflower oil in water emulsion on the 3 separate study days: Coarse, Coarse+LBG, and Fine+LBG. The lower part of the panel shows the corresponding fat-only images. These show that the LBG-stabilized emulsions did not phase separate in the stomach, whereas the Coarse meal shows a clear creamed fat layer on top of the stomach contents. Coarse, 20% oil and water emulsion with 6-μm mean droplet size; Coarse+LBG, 20% oil and water emulsion with 6-μm mean droplet size and 0.5% locust bean gum; Fine+LBG, 20% oil and water emulsion with 0.4-μm mean droplet size and 0.5% locust bean gum; LBG, locust bean gum.

FIGURE 3

Volume of the gastric contents over time for healthy young adults after they consumed the 3 meals containing a 20% sunflower oil in water emulsion on the 3 separate study days: Coarse, Coarse+LBG, and Fine+LBG. Values are means ± SEMs, n = 11. The arrow indicates the meal time. Coarse, 20% oil and water emulsion with 6-μm mean droplet size; Coarse+LBG, 20% oil and water emulsion with 6-μm mean droplet size and 0.5% locust bean gum; Fine+LBG, 20% oil and water emulsion with 0.4-μm mean droplet size and 0.5% locust bean gum; LBG, locust bean gum.

FIGURE 4

Lipid:water ratio measured from spectroscopy voxels placed in the upper (A) and the lower (B) part of the stomach of healthy young adults after consumption of the 3 meals containing a 20% sunflower oil in water emulsion on the 3 separate study days: Coarse, Coarse+LBG, and Fine+LBG. Values are means ± SEMs, n = 11. The arrow indicates the meal time. Coarse, 20% oil and water emulsion with 6-μm mean droplet size; Coarse+LBG, 20% oil and water emulsion with 6-μm mean droplet size and 0.5% locust bean gum; Fine+LBG, 20% oil and water emulsion with 0.4-μm mean droplet size and 0.5% locust bean gum; LBG, locust bean gum.

FIGURE 5

On the left side of the panel is a coronal anatomic “roadmap” dual-echo MRI image. The other images are corresponding small bowel water images taken across the small bowel of the same healthy young adult at time t = 4 h after consumption of each of the 3 meals containing a 20% sunflower oil in water emulsion on the 3 separate study days: Coarse, Coarse+LBG, and Fine+LBG. These images show the large amount of freely mobile fluid present in the small bowel in response to the fat emulsion meals. Coarse, 20% oil and water emulsion with 6-μm mean droplet size; Coarse+LBG, 20% oil and water emulsion with 6-μm mean droplet size and 0.5% locust bean gum; Fine+LBG, 20% oil and water emulsion with 0.4-μm mean droplet size and 0.5% locust bean gum; LBG, locust bean gum.

FIGURE 6

Small bowel water content volume over time for healthy young adults after they consumed the 3 meals containing a 20% sunflower oil in water emulsion on the 3 separate study days: Coarse, Coarse+LBG, and Fine+LBG. Values are means ± SEMs, n = 11. Coarse, 20% oil and water emulsion with 6-μm mean droplet size; Coarse+LBG, 20% oil and water emulsion with 6-μm mean droplet size and 0.5% locust bean gum; Fine+LBG, 20% oil and water emulsion with 0.4-μm mean droplet size and 0.5% locust bean gum; LBG, locust bean gum.

FIGURE 7

Weight of food consumed ad libitum from a pasta meal by healthy young adults after they consumed the 3 meals containing a 20% sunflower oil in water emulsion on the 3 separate study days: Coarse, Coarse+LBG, and Fine+LBG. Values are means ± SEMs, n = 11. Labeled means without a common letter differ, P < 0.05. Coarse, 20% oil and water emulsion with 6-μm mean droplet size; Coarse+LBG, 20% oil and water emulsion with 6-μm mean droplet size and 0.5% locust bean gum; Fine+LBG, 20% oil and water emulsion with 0.4-μm mean droplet size and 0.5% locust bean gum; LBG, locust bean gum.