Effect of meal volume and calorie load on postprandial gastric function and emptying: studies under physiological conditions by combined fiber-optic pressure measurement and MRI

Abstract

This study assessed the effects of meal volume (MV) and calorie load (CL) on gastric function. MRI and a minimally invasive fiber-optic recording system (FORS) provided simultaneous measurement of gastric volume and pressure changes during gastric filling and emptying of a liquid nutrient meal in physiological conditions. The gastric response to 12 iso-osmolar MV-CL combinations of a multinutrient drink (MV: 200, 400, 600, 800 ml; CL: 200, 300, 400 kcal) was tested in 16 healthy subjects according to a factorial design. Total gastric volume (TGV) and gastric content volume (GCV = MV + secretion) were measured by MRI during nasogastric meal infusion and gastric emptying over 60 min. Intragastric pressure was assessed at 1 Hz by FORS. The dynamic change in postprandial gastric volumes was described by a validated three-component linear exponential model. The stomach expanded with MV, but the ratio of GCV:MV at t(0) diminished with increasing MV (P < 0.01). Postprandial changes in TGV followed those of GCV. Intragastric pressure increased with MV, and this effect was augmented further by CL (P = 0.02); however, the absolute pressure rise was <4 mmHg. A further postprandial increase of gastric volumes was observed early on before any subsequent volume decrease. This "early" increase in GCV was greater for smaller than larger MV (P < 0.01), indicating faster initial gastric emptying of larger MV. In contrast, volume change during filling and in the early postprandial period were unaffected by CL. In the later postprandial period, gastric emptying rate continued to be more rapid with high MVs (P < 0.001); however, at any given volume, gastric emptying was slowed by higher CL (P < 0.001). GCV half-emptying time decreased with CL at 18 +/- 6 min for each additional 100-kcal load (P < 0.001). These findings indicate that gastric wall stress (passive strain and active tone) provides the driving force for gastric emptying, but distal resistance to gastric outflow regulates further passage of nutrients. The distinct early phase of gastric emptying with relatively rapid, uncontrolled passage of nutrients into the small bowel, modulated by meal volume but not nutrient composition, ensures that the delivery of nutrients in the later postprandial period is related to the overall calorie load of the meal.

Fluid, energy and nutrient recovery via ad libitum intake of different fluids and food

“…While the present study had no beverage only trial for direct comparisons, results from previous experiments suggest the consumption of food with fluid can enhance fluid retention (18,25). The consumption of food with fluid may result in higher nutrient and energy intakes and greater gastric distention, which together, are likely to delay gastric emptying (16). To date, only limited food items have been examined (rice/beef meal (18), beef jerky (25)) and on both occasions food and fluid intakes were prescribed.…”

Measurement of oro-caecal transit time by magnetic resonance imaging

“…In this series, the median BT-OCTT was longer than 101 min obtained in a previous study in a large number of healthy volunteers in the seated position (26). An upright position may promote gastric emptying and bolus transit through the small intestine as documented by previous MRI studies (30,31); however any effect is likely to be small and unlikely to confound diagnosis of SIBO using the combined technique. Finally, inter observer agreement of MR-OCTT measurements was near perfect, but we did not test reproducibility of combined MRI-LHBT examination.…”

“…Scintigraphy has good sensitivity and specificity providing similar measurements of OCTT by using both solid and liquid meal (28), but is time consuming, relatively costly, sometimes difficult to interpret due to overlapping loops of small intestine and the caecum, and utilizes ionizing radiations (8,28). MRI was recently applied to evaluate GI structure and function (29)(30)(31) and to detect the presence of gas or liquids and the movement of fluid through the GI tract (32)(33)(34).…”

Drug release from matrix tablets: physiological parameters and the effect of food

“…They also found a further increase in the gastric volumes due to gastric secretions before the volumes started to decline. They found that this increase was independent of caloric load and greater for smaller rather than the larger infused meals [52].…”

“…The volume of liquid in the GI tract can affect the amount and potentially the concentration of the dissolved drug. Kwiatek et al [52] attributed a progressive decrease in initial gastric volume as a function of meal volume to a larger portion of liquid nutrient passing through the small intestine during a rapid early emptying phase. They also found a further increase in the gastric volumes due to gastric secretions before the volumes started to decline.…”