Gastric Emptying of Indigestible versus Digestible Oils and Solid Fats in Normal Humans

Recent scintigraphic studies indicate thatlipolytic products in the small intestine do not inhibitgastric emptying of fat as potently as previouslysuggested by studies that compared a liquid indigestible oil with a solid digestible fat. The olderstudies left open the confounding possibility that solidfats emptied differently than liquid oil. We studiedeight normal subjects who ingested four meals in which fat was (1) liquid, digestible Criscooil, (2) liquid, indigestible sucrose polyester oil, (3)digestible, solid Crisco, and (4) indigestible, solidolestra. Fats were labeled with iodine-123, and their gastric emptying was followed with agamma camera. Indigestible fats (whether liquid orsolid) emptied consistently faster than digestible fats(P < 0.005), although differences were small. Solid fats emptied about as rapidly as oils in thefirst hour; but more slowly thereafter (P < 0.01). Acomparison of present scintigraphic with older studiessuggested that solid fats were not well tracked by duodenal, marker-perfusion techniques, whichmisled previous investigators.     

Gastric emptying of lactose and milk in subjects with lactose malabsorption

Six lactose absorbers (LA) and 5 lactose malabsorbers (LM) had tests of gastric emptying with 750-ml meals of glucose in water, lactose in water, plain milk, and chocolate milk. The glucose and lactose meals emptied in a similar fashion in LA and LM subjects with a significant decrease in gastric emptying as the osmolarity of the meals was doubled. If the data are normalized by dividing lactose emptying by the emptying of glucose meals of twice the osmolality in each individual, the lactose malabsorbers empty significantly more lactose. Both LA and LM subjects emptied comparable amounts of milk meals having similar osmolarity. Chocolate milk, which had a higher osmolality than plain milk, emptied more slowly than plain milk in both groups, and this difference was significant in the LM group.     

Influence of meal weight and caloric content on gastric emptying of meals in man

This study was designed to assess the relative influence of meal weight and caloric content on gastric emptying of liquid and solid meals in man. A dual radioisotopic method which permits noninvasive and simultaneous measurement of liquid-and solid-phase emptying by external gamma camera techniques was employed. Nine healthy volunteer subjects ingested 50-,300-, and 900-g lettuce and water meals adjusted to either 68, 208, or 633 kcal with added salad oil. The following observations were made: (1) absolute emptying rates (grams of solid food emptied from the stomach per minute) increased directly and significantly with meal weight; (2) increasing meal total caloric content significantly slowed solid food gastric emptying but did not overcome the enhancing effect of meal weight; and (3) liquid emptying rates were uninfluenced by meal total kcal amount.The authors wish to express their appreciation to the Salt Lake Veterans Medical Center, Medical Research Service for their support.     

Effect of ethanol upon gastric emptying.

The effect of ethanol upon gastric emptying in healthy human subjects was studied by measuring the gastric emptying rates of three 750 ml meals, the osmolalities, energy densities, and pH of which were similar. Meal A, which contained 80 ml alcohol, emptied more rapidly than meal B, which contained 40 ml ethanol and 63.3 g dextrose; and meal B emptied more rapidly than meal C, which contained 126.6 g dextrose but no ethanol. The slower rate of emptying of the dextrose meal (C) was not due to an increased gastric secretory rate, as serial measurements of gastric pH were substantially and significantly higher with this than with the other two meals; nor was it due to a greater degree of duodenogastric reflux, as serial measurements of gastric bile acid concentrations were similar for the three meals. We conclude that the duodenal osmoreceptor mechanism is relatively insensitive to ethanol; that the relationship between energy density and gastric emptying rate does not hold in the case of ethanol; and that the gastro-oesophageal reflux which occurs in response to ethanol is not due to impairment of gastric emptying.     

Gastric emptying after roux-y and billroth-I gastrectomy depends on viscosity of meal and contractile patterns of small intestine in dogs

The aim of the study was to examine gastrointestinal motility after distal gastrectomy and the influence of meal viscosity on gastric emptying. Gastrointestinal motility and gastric emptying of acaloric meals with different viscosities were measured in normal dogs and after a two-thirds gastrectomy with Billroth-I or Roux-Y gastroenterostomy. After distal gastrectomy, gastric emptying depended on the viscosity of the meal, as in normal dogs. Acaloric viscous meals emptied significantly faster in the Billroth-I than in the Roux-Y group due to different contractile patterns of the duodenum and jejunum. In comparison to normal dogs, gastric emptying of viscous meals was accelerated in the Billroth-I and delayed in the Roux-Y group. Several motility parameters of the stomach and intestine differed between the normal and gastrectomized dogs. Thus, after distal gastrectomy, the viscosity of the meal and the contractile patterns of the small intestine are important determinants of gastric emptying.Studies were supported by the Deutsche Forschungsgemeinschaft, grant Eh 64/3-1.     

Gastric emptying of liquids in normal subjects and patients with healed duodenal ulcer disease

We have characterized the dose-response of inhibition of gastric emptying by acid, glucose, and fat in duodenal ulcer (DU) patients and normals (N) matched by age and sex. Gastric emptying was measured by the George technique while intragastric pH was maintained constant by intragastric titration. Acid, glucose, and fat inhibited gastric emptying in a dose-dependent fashion in both groups. DU patients emptied all three types of meals faster than normals, but differences were only seen at the lower doses of glucose or with the less potent doses of acid and fat. With low concentrations of glucose and at all concentrations of acid, DU patients emptied the meals faster than normals only in the first 5 min; but with fat the differences persisted throughout the 30-min test. Differences in gastric emptying of liquid meals in DU patients vs normals are small, and they occur with nutrient as well as acid meals. The variable responses obtained with the different concentrations may explain the inconsistencies found by other workers.     

Gastric emptying and pancreatic polypeptide response to carbohydrate meals

This study examined pancreatic polypeptide responses to isocaloric meals of radioactively labeled glucose or starch in six normal and seven vagotomized subjects. Liquid glucose meals were ingested with the subject both erect and supine and starch meals were ingested in the upright posture as a solution and as solid balls. In normal subjects, each meal left the stomach at a similar rate and the resultant pancreatic polypeptide responses were not significantly different from one another. Emptying rates varied markedly in vagotomized subjects depending upon the physical consistency of the carbohydrate ingested and the patient's posture. Despite these differences, pancreatic polypeptide responses to each meal were almost identical. These studies demonstrate that the pancreatic polypeptide response to carbohydrate meals is still present several years after vagotomy and is unaffected by alterations in the rate of gastric emptying after vagotomy and by the physical consistency and chemical nature of the carbohydrate ingested.     

Postcibal gastric emptying of pancreatin pellets: effects of dose and meal oil

To treat pancreatic exocrine insufficiency, physicians often prescribe enterically coated pellets of pancreatin to be taken with meals. The pellets are only partially effective in correcting the digestion and absorption of fat. We sought to determine in normal subjects whether emptying of pellets from the postcibal stomach was dose-related and whether the gastric emptying of lipophilic Creon-20 or Pancrease was altered by the presence or the absence of oil in a meal. Gastric emptying of pellets surface-labeled with ^113mIn or ^99mTc was followed with a gamma camera for 300 min after isocaloric meals. From our observations, we concluded that gastric emptying of 0.28–1.12 g of 1-mm or 2-mm pellets was dose-related (P < 0.01) and emptying of neither Creon-20 nor Pancrease was much affected by oil in the meal.     

Relation between gastric emptying rate and energy intake in children compared with adults.

Measurement of gastric emptying rate of solids in children is difficult because the available methods are either invasive or induce a substantial radiation burden. In this study the newly developed 13C octanoic acid breath test was used to examine the gastric emptying rate of solids and milk in healthy children and to compare gastric emptying in children and adults. Fifteen healthy children and three groups of nine healthy adults were studied, using three different test meals labelled with 50 mg of 13C octanoic acid: a low caloric pancake (150 kcal), a high caloric pancake (250 kcal), and 210 ml of milk (134 kcal). Breath samples were taken before and at regular intervals after ingestion of the test meal, and analysed by isotope ratio mass spectrometry. The gastric emptying parameters were derived from the 13CO2 excretion curves by non-linear regression analysis. No significant difference was found between children and adults in the emptying rate of the low caloric solid test meal. In children as well as in adults, increasing the energy content of the solid meal resulted in a significantly slower emptying rate. The milk test meal, however, was emptied at a faster rate in adults and at slower rate in children compared with the low caloric solid test meal. Moreover, the emptying rate of milk in children was significantly slower than in adults. In conclusion, a similar gastric emptying rate of solids but a slower emptying of full cream milk was shown in children of school age compared with adults, using the non-radioactive 13C octanoic acid breath test.     

Effects of meal composition on gallbladder and gastric emptying in man

Cholecystogastric scintigraphy, utilizing [^99mTc]HlDA to label the gallbladder contents and [¹¹¹In]DTPA to label different meals, was utilized to determine the relationships between gallbladder and gastric emptying after meals of differing composition. Gallbladder emptying was determined in response to a multicomponent meal and to monocomponent fat, carbohydrate, and protein meals and in response to isotonic and hypertonic dextrose and isotonic and hypertonic saline. Also, the gallbladder emptying responses to equivalent multicomponent solid and liquid meals were compared. Significant gallbladder emptying was observed in response to the multicomponent meal and the monocomponent fat, carbohydrate, and protein meals. The most rapid and complete gallbladder emptying was seen with the multicomponent meal and the monocomponent fat meal. Significant gallbladder emptying was stimulated, not only by isotonic and hypertonic dextrose, but also by hypertonic saline. The gallbladder emptied more rapidly after a liquid than after a solid meal.     

Different gastric,pancreatic, and biliary responses to solid-liquid or homogenized meals

We have compared responses to an ordinary solid-liquid (S) meal and to a homogenized (H) meal of identical composition (sirloin steak, bread, butter, ice cream with chocolate syrup, and water) by measuring simultaneously postprandial gastric, pancreatic, and biliary functions by marker-perfusion techniques. Responses to each (S or H) meals differed strikingly both in magnitude and pattern. S meals elicited a stronger early gastric secretory response (acid, pepsin, and volume) which compensated for faster initial emptying and resulted in higher gastric acidity and volume than after H meals. Further, nutrients ingested with S meals were emptied at a slower rate than H (as evidenced by a more gradual decline in intragastric buffer and osmolality, as well as time required for complete emptying of the meal). This, in turn, prolonged pancreatic and biliary responses since stimulation of these organs continued for as long as meal was delivered into the duodenum. However, early biliary outputs (gallbladder response) were less after S than H, probably because nutrients entered the duodenum more slowly and were initially diluted by rapidly emptying water. The physical characteristics of each meal (encompassing appearance, taste, and form of ingestion) probably accounted for early differences in digestive responses. Later, interactions between gastric (motor and secretory), pancreatic, and biliary functions played a major role. Our findings suggest that gastric, pancreatic, and biliary responses to liquid test meals introduced into the stomach may differ substantially from the presumably more physiological response to ordinary solid-liquid meals.Dr. Summerskill died March 9, 1977.This investigation was supported in part by Research Grant AM 6908 from National Institutes of Health.     

Gastric emptying and intragastric distribution of lipids in man

We measured gastric emptying of fat and water from a solid-liquid meal in healthy volunteers using a tubeless scintigraphic method. Selenium-75 glycerol triether, incorporated in butter, was the lipid-phase marker, and technetium-99m, ingested with 250 ml water, the non-lipid-phase marker. In seven of these subjects we also measured the gastric emptying of solids and liquids with technetium-99m bound to cooked egg whites as the solid-phase marker and indium-111 ingested with 250 ml water as the marker of the solid and aqueous phases. Emptying and intragastric repartition of each marker were measured by detection of radioactivity changes over the abdominal area using a gammacamera. The stability and the specificity of the labeling was checked for each marker. Mean gastric emptying rate (expressed as percentage ingested marker emptied per hr) of lipids (17.4±2.4) was much lower than that of the rest of the meal (34.2±1.8) and slightly, but significantly, lower than that of solids (22.8±1.8). An intragastric layering of fat above nonlipids was observed only after the first postprandial hour and remained moderate. Thus, lipids are emptied more slowly than any other component of an ordinary meal, and this is not due only to layering of fat above water.The authors thank Dr. DeJong of the Byk-Mallinckrodt Laboratories for kindly supplying us with [⁷⁵Se]GTE, and Dr. Chavaudra for assistance in radiation exposure determination.     

Effects of nutrients on gastrointestinal motility and gastric emptying after distal gastrectomy with Roux-Y gastrojejunostomy in dogs

The aim of the study was to clarify whether nutrients are still capable of slowing gastric emptying following Roux-Y gastrectomy, as in normal dogs. Gastrointestinal motility and gastric emptying of acaloric and nutritive meals with different viscosities were measured in normal dogs and after a two-thirds Roux-Y gastrectomy. In gastrectomized dogs low-viscosity nutritive meals emptied unduly rapidly in an initial phase, although the frequency and spread of contractions, ie, the propulsive activity of the jejunal Roux limb were diminished. A slow emptying rate during the following period was due to a long-lasting inhibition of gastric and jejunal motility. Medium-viscosity nutritive meals emptied in gastrectomized dogs as slowly as in normal animals, but this effect was primarily caused by the meal viscosity and only secondarily by the nutrients. It is concluded that following Roux-Y gastrectomy a regulation of gastric emptying is preserved; however, the onset of an effective control is delayed, resulting in a rapid initial emptying of low-viscosity meals.Studies were supported by the Deutsche Forschungsgemeinschaft grant Eh 64/3-1.     

Superior mesenteric artery blood flow and gastric emptying in humans and the differential effects of high fat and high carbohydrate meals.

This study was designed to determine if the differential effect of high fat and high carbohydrate meals on mesenteric blood flow is a result of changed gastric emptying rate. Eight healthy men were studied twice. Superior mesenteric artery blood flow (Doppler ultrasound) was measured before and after a 2.5 MJ meal (either 74% of the energy as carbohydrate or 71% as fat). Emptying of meals was followed by gamma-scintigraphy. The pattern of the superior mesenteric artery blood flow response was different after the two meals (interaction effect p < 0.001 analysis of variance), with a far more sustained response after fat. The time by which half the meal had emptied (t50) was also significantly greater after fat (p < 0.02). Superior mesenteric artery blood flow corresponding to t50 was 449 ml/min after carbohydrate and 592 ml/min after fat. There was a significant curvilinear relation between the superior mesenteric artery blood flow response and gastric emptying after carbohydrate (r2 = 0.94) and no relation at all after fat. This study confirms the finding that ingestion of meals with a high fat content slows gastric emptying compared with meals with a high carbohydrate content in healthy volunteers. A more sustained mesenteric hyperaemia was also recorded after the fat meal compared with the carbohydrate meal. The relation, however, between the volume of meal remaining in the stomach and the mesenteric response was considerably different after the two meals. Further study is required to elucidate the mechanism behind the vascular responses recorded in the mesenteric bed after food in humans.     

Human postprandial gastric emptying of 1-3-millimeter spheres

Microspheres of pancreatin should empty from the stomachs of patients with pancreatic insufficiency as fast as food. The present study was undertaken in 26 healthy subjects to identify the size of spheres that would empty from the stomach with food and to determine whether different meals alter this size. Spheres of predefined sizes were labeled with 113mIn or 99mTc. Using a gamma-camera, we studied the concurrent gastric emptying of spheres labeled with 113mIn and of chicken liver labeled with 99mTc in 100-g, 154-kcal or 420-g, 919-kcal meals, or the concurrent emptying of 1-mm vs. larger spheres. One-millimeter spheres emptied consistently (p less than 0.01, paired t-test) faster than 2.4- or 3.2-mm spheres when ingested together with either the 420- or 100-g meals. Thus, in the 1-3-mm range of diameters, sphere size was a more important determinant of sphere emptying than meal size. Statistical analyses indicated that spheres 1.4 +/- 0.3 mm in diameter with a density of 1 empty at the same rate as 99mTc-liver. Our data indicate some commercially marketed microspheres of pancreatin will empty too slowly to be effective in digestion of food.     

Small particle size of a solid meal increases gastric emptying and late postprandial glycaemic response in diabetic subjects with gastroparesis

Our goal was to investigate if food of small particle size increases the gastric emptying rate and lessens the fall in postprandial blood glucose in seven subjects with Type 1 diabetes and gastroparesis. Two solid meals of identical composition but of different particle size, with 5MBq (99m)Tc added to the meals, were ingested in randomized order in seven subjects with Type 1 Diabetes Mellitus and gastroparesis and seven healthy subjects. During 180min blood glucose and insulin concentrations were measured and gastric emptying of the ingested meals was registered by a gamma camera. The lag phase in the stomach was significantly shorter, the radioactivity remaining in the stomach after 120min (T(120)) was significant less and the postprandial blood glucose dip was less and of shorter duration after a small particle (SP) meal, compared to a large particle (LP) meal in diabetic subjects. Gastric emptying did not differ significantly between groups after an SP meal. Food of small particle size increases the gastric emptying rate and reduces the postprandial blood glucose dip in both magnitude and duration in Type 1 diabetic subjects with gastroparesis, which is likely to be of importance in achieving good metabolic control.     

Effect of vagotomy on gastric emptying

To determine whether pyloroplasty or a disrupted osmoreceptor mechanism is primarily responsible for the increased gastric emptying of hypertonic sugar solutions after vagotomy and pyloroplasty, test meals of 10% glucose (556 mOsm/kg) and NaCl (200 mOsm/kg) were administered to duodenal ulcer patients with no prior operation, after vagotomy and pyloroplasty, and in patients with prior vagotomy, hiatal herniorrhaphy, and no pyloroplasty. Hypertonic glucose meals were emptied more rapidly than normal after both operations. The hypotonic NaCl meal was emptied no faster postoperatively than it was preoperatively. The results rule out pyloroplasty as the primary factor responsible for the observed increased rate of gastric emptying. Instead, the data suggest that the osmoreceptor mechanism described by Hunt is disrupted by vagotomy.Presented in part at the Midwestern Section. American Federation for Clinical Research, Chicago, Ill. Nov 1, 1969.Supported by Veterans Administration Part II Research Funds.     

Motor mechanisms associated with slowing of the gastric emptying of a solid meal by an intraduodenal lipid infusion

The aim of this study was to define better the motor phenomena associated with the slowing of gastric emptying by a duodenal lipid infusion. Antral, pyloric and duodenal motility were recorded in 10 healthy subjects with a manometric assembly which incorporated multiple perfused side-holes and a sleeve sensor positioned astride the pylorus. The gastric emptying of a standard solid meal and the distribution of the ingesta between the proximal and distal stomach were monitored with a radionuclide technique. A triglyceride emulsion was infused into the duodenum for 45 min once 25% of the meal had emptied. The infusion caused significant slowing in the rate of gastric emptying (P less than 0.01). This slowing in gastric emptying was associated with the suppression of pressure waves in the distal antrum (P less than 0.01) and proximal duodenum (P less than 0.01), the induction of pressure waves isolated to a narrow pyloric segment (P less than 0.01), and a redistribution of ingesta from the distal to proximal stomach. These findings suggest that pressure waves isolated to the pylorus, changes in the intragastric distribution of ingested food, and changes in proximal duodenal motility may all act in concert with changes in antral motility to regulate the gastric emptying of solids.     

Assessment of gastric emptying using a low fat meal: establishment of international control values

OBJECTIVE: The diagnosis of gastroparesis implies delayed gastric emptying. The diagnostic gold standard is scintigraphy, but techniques and measured endpoints vary widely among institutions. In this study, a simplified scintigraphic measurement of gastric emptying was compared to conventional gastric scintigraphic techniques and normal gastric emptying values defined in healthy subjects. METHODS: In 123 volunteers (aged 19-73 yr, 60 women and 63 men) from 11 centers, scintigraphy was used to assess gastric emptying of a 99Tc-labeled low fat meal (egg substitute) and percent intragastric residual contents 60, 120, and 240 min after completion of the meal. In 42 subjects, additional measurements were taken every 10 min for 1 h. In 20 subjects, gastric emptying of a 99Tc-labeled liver meal was compared with that of the 99Tc-labeled low fat meal. RESULTS: Median values (95th percentile) for percent gastric retention at 60, 120, and 240 min were 69% (90%), 24% (60%) and 1.2% (10%) respectively. A power exponential model yielded similar emptying curves and estimated T50 when using images only taken at 1, 2 and 4 h, or with imaging taken every 10 min. Gastric emptying was initially more rapid in men but was comparable in men and women at 4 h; it was faster in older subjects (p < 0.05) but was independent of body mass index. CONCLUSIONS: This multicenter study provides gastric emptying values in healthy subjects based on data obtained using a large sample size and consistent meal and methodology. Gastric retention of >10% at 4 h is indicative of delayed emptying, a value comparable to those provided by more intensive scanning approaches. Gastric emptying of a low fat meal is initially faster in men but is comparable in women at 4 h; it is also faster in older individuals but is independent of body mass.     

Comparative study of gastric emptying of digestible and nondigestible solids in normal man and duodenal ulcer patients

Few studies have compared the gastric emptying of digestible and non-digestible solids in man. In 9 normal subjects and 16 duodenal ulcer patients, we measured simultaneously and during 3 h, the gastric emptying of: (a) radioopaque pellets (n = 100; volume = 30 mm3) ingested with an ordinary meal (450 kcal, 500 ml) and counted on X-ray series; and (b) digestible solids of the meal (99mtechnetium tagged egg white) detected by an isotopic method. Gastric emptying of liquids (labelled with 113mindium DTPA) was also determined. In normal subjects, emptying rates of the pellets was 5 +/- 2 p. 100 per hour while that of digestible solids was 29 +/- 1 p. 100 per hour (P less than 0.01). No correlation was evidenced between the emptying rates of either kind of solids. Emptying of liquids was faster than that of both digestible solids and pellets. Similar results were obtained in duodenal ulcer patients; no significant difference was found between patients and normal subjects for the three meal phases tested. These results are consistent with the hypothesis that digestible solids are retained in stomach until they are ground, and show that inert particles do not always reflect the gastric emptying of natural solids of the meal.