Long-term evolution of the effect of bran ingestion on meal-induced glucose and insulin responses in healthy man

The long-term effect (7 wk) of the addition in the diet of 20 g of wheat bran was studied in five healthy subjects. Blood glucose and plasma insulin were assayed during test-meals taking place before (I), then 10 days (II), 24 days (III), and 45 days (IV) after daily ingestion of wheat bran. Bran addition leads to a time progressive reduction of meal-induced glucose response. This effect was the strongest during meal III, at 30 min (from 7.38 +/- 0.11 to 5.0 +/- 1.11 mmol/l; p less than 0.05) and at 60 min (from 5.94 +/- 0.61 to 3.88 +/- 0.78 mmol/l; p less than 0.05). Insulin response remained identical during the first three test meals. It increased then in a significant manner during meal IV, at 60 min (From 45.5 +/- 12.3 to 61.8 +/- 8.9 microU/ml; p less than 0.02), and at 120 min (from 41.2 +/- 16.3 to 61.0 +/- 16.0 microU/ml; p less than 0.05). The causes of the reduction of glucose response could be potential gastric emptying and intestinal transit increases. The exact mechanism of the improved long-term glucose tolerance seen in brain is not obvious nor is the reason for the enhanced insulin response seen later.     

Does guar gum improve post-prandial hyperglycaemia in humans by reducing small intestinal contact area?

The possibility that viscous polysaccharides, such as guar gum, could lower post-prandial blood glucose levels in part by restricting carbohydrate solutions to a smaller area of small intestine was investigated in twenty healthy human volunteers. Addition of guar gum (22.5 g/l) delayed the mouth-to-caecum transit time of a hypotonic lactulose drink, but did not affect gastric emptying. When a 250 ml solution containing 50 g glucose was confined to a 550 mm length of intestine by an occluding balloon attached to an intestinal tube, maximum blood glucose response was significantly reduced (P less than 0.05) though only by 0.9 mmol/l. Addition of guar gum (36 g/l) had no effect on the distribution of a radio-labelled glucose drink (250 ml; 200 g glucose/l) in the small intestine, monitored using a gamma camera, although it significantly delayed gastric emptying (t 1/2 (min): guar gum v. control 115 (SE 15) v. 73 (SE 8)). Reduced contact area is unlikely to be one of the mechanisms by which guar gum improves glucose tolerance.     

Sustained pectin ingestion: effect on gastric emptying and glucose tolerance in non-insulin-dependent diabetic patients

The effects of sustained pectin ingestion on gastric emptying, glucose tolerance, and hormone responses were studied in 12 stable, non-insulin-dependent (type 2) diabetic patients. Patients were placed on a 2400 kcal, low-fiber (3 g) diet for 2 wk, followed by 4 wk of an isocaloric diet supplemented with 20 g apple pectin/d. Gastric-emptying half-time, plasma glucose, glucagon, and human pancreatic polypeptide levels were determined. Gastric-emptying half-time was prolonged 43% (p less than 0.025) by pectin supplementation and returned to normal 3 d after its discontinuation. Fiber supplementation decreased the incremental area under the glucose tolerance curve from 34.8 +/- 3.0 to 27.9 +/- 3.2 mmol/L (p less than 0.01) but did not affect hormonal responses to a meal. Sustained pectin ingestion slowed the gastric-emptying rate and improved glucose tolerance; however, a direct relationship could not be demonstrated between changes in gastric emptying and changes in the incremental area under the glucose curve (r = 0.22).     

Effects of xylitol on gastric emptying and food intake

We studied the effects of xylitol, the pentose-sugar alcohol, on gastric emptying of the solid-food component of a complex meal. Gastric emptying was measured in human volunteers by utilizing a standardized radiolabeled scrambled-egg meal. After ingestion of 25 g xylitol, gastric emptying was markedly prolonged (T-1/2 58 +/- 5 min control vs 91 +/- 7 min after xylitol [p less than 0.01]). Since delayed gastric emptying may affect food intake, we evaluated the effects of xylitol on calorie intake. Food intake after oral preloading with water resulted in intake of 920 +/- 60 kcal vs 690 +/- 45 kcal after 25 g of xylitol. In contrast, a preload of glucose, fructose, or sucrose failed to suppress food intake. Although xylitol decreased food intake and also delayed gastric emptying, these effects may be unrelated. Our data suggest a role for xylitol as a potentially important agent in dietary control.     

Effect of guar gum on gastric emptying in growing pigs

1. Simple gastric cannulas were surgically fitted to four pigs, initially of 30 kg live weight, to examine the effects of guar gum on gastric emptying. 2. Four semi-purified high-fat diets based on starch, casein, soya-bean oil and tallow were given to each pig. They contained 0 (control), 20, 40 or 60 g powdered guar gum/kg diet. The meals as fed contained 257 g dry matter (DM)/kg. 3. The contents of the stomach were evacuated, with rinsing, before feeding or 0.5, 1, 2 or 4 h after feeding. 4. The mean pH of the digesta was unaffected by guar gum until 4 h after feeding when the value increased as the amount of guar gum in the diet rose. 5. The only significant effects of guar gum on the emptying of digesta and its components (compared with the control diet) were to reduce the rate of emptying of (a) digesta 1 h after feeding (60 g/kg diet) and 4 h after feeding (40 and 60 g/kg diets), (b) dry matter and glucose 1 h after feeding (60 g/kg diet), (c) nitrogen 1 h after feeding (60 g/kg diet) and 4 h after feeding (40 and 60 g/kg diets). 6. When expressed on a half-time (T50) basis, the emptying of digesta and N (but not of DM and glucose) were significantly slower for diets containing 40 and 60 g guar gum/kg than for the control diet. 7. The apparent viscosity of the gastric digesta ranged between 0.5 and 23.7% of the values for the diets as consumed. 8. It was concluded that the effects of guar gum on gastric emptying of high-solid meals were small, and that this was unlikely to be an important aspect of the mechanism by which guar gum reduces postprandial blood glucose concentrations.     

Effect of guar gum added to the diet of patients with duodenal ulcer

In a randomized, double-blind, controlled clinical study, the effects of 5 g of guar gum, a dietary fiber composed of galactose and mannose, or placebo added to the diet of 20 patients with duodenal ulcer for 1 wk each were examined. Ten patients derived evident benefit and five some help from guar gum, on comparing symptoms during administration of guar gum with those experienced earlier or during the placebo week, whereas four patients found that neither guar gum nor placebo had any effect (p less than 0.001). The beneficial effect was associated with increased feelings of repletion after meals. Patients with fewest symptoms benefited only slightly, or not at all, from guar gum. In one patient, guar gum abolished pain felt earlier and on placebo, but also caused severe gastric retention after meals. This patient had pyloric stenosis. In patients who were intolerant to berries, fruits, sugar, sweet rolls, and pizza these foodstuffs were better tolerated during guar gum administration. The diarrhea which occurs in some patients ingesting guar gum was avoided by giving low initial doses. In three patients unpalatability of guar gum was a minor complaint. It is concluded that guar gum is helpful to many patients with uncomplicated duodenal ulcer, but that it is harmful to those having increased gastric emptying, eg, pyloric stenosis patients, and that guar gum may exert its effects by increasing gastric emptying time.     

The effect of ispaghula (Fybogel and Metamucil) and guar gum on glucose tolerance in man

The effects of incorporating Fybogel (3.5 and 7 g doses), Metamucil (7 g) or guar gum (2.5 and 14.5 g doses) in a drink containing 50 g glucose on plasma glucose, plasma insulin and gastric emptying were studied in thirty-eight normal volunteers. In addition, the effects of Fybogel (7 g) on glucose tolerance, plasma insulin and gastric emptying were measured in fourteen non-insulin-dependent diabetics. Both doses of guar gum significantly lowered plasma glucose and plasma insulin responses to the oral glucose load in normal subjects, although 14.5 g guar gum did not delay the half-time for gastric emptying. Neither Fybogel nor Metamucil had significant effects on plasma glucose responses in normal subjects. In addition, Fybogel (at either dose) had no significant effects on plasma insulin levels, or on gastric emptying in normal subjects or on plasma glucose and insulin responses in diabetic patients. The viscosity of ispaghula solutions ( Fybogel ) was lower than that of guar gum solutions.     

The effects of complex polysaccharides on growth,digestibility and blood parameters in pair-fed chicks

A pair-feeding study was conducted on chicks to evaluate the growth-depressing and hypocholesterolemic effects of guar gum and pectin compared to other sources of dietary fiber. Fibers were fed so that the diet contained 2% hemicellulose or related complex carbohydrate from wheat bran, corn bran, a wood hemicellulose product, guar gum or pectin. A diet containing 10% wheat bran was also fed. Despite pair feeding, final body weights of guar gum-fed chicks were lower than that of all other groups at four weeks. Pectin-fed chicks, though heavier than those fed guar gum, weighed less than those fed the control, wood hemicellulose or wheat bran at either level. Digestibility of the diets appeared to influence growth rates. Metabolizable energy and feed efficiency in guar gum and pectin-fed chicks were also lower, and excreta weight was greater than in chicks fed other sources of fiber. Although not correlated to body weight, total serum cholesterol levels in chicks fed guar gum were lower than those of all other groups. Post-prandial glucose levels in whole blood were highest in chicks fed wood hemicellulose and lowest in those fed guar gum, corn bran or 10% wheat bran.     

The effect of different dosages of guar gum on gastric emptying and small intestinal transit of a consumed semisolid meal

BACKGROUND: There is no consensus about the effect of guar gum supplementation on gastrointestinal transit. It has been suggested that guar gum slows gastric emptying and intestinal transit, thus inducing an increased feeling of satiety. OBJECTIVE: To investigate whether addition of guar gum to a semisolid meal affects gastrointestinal transit. DESIGN: Eight male subjects were randomly studied four times. They consumed a standard semisolid test meal containing either 0 g, 2.5 g, 3.5 g, or 4.5 g of guar gum. The test meals contained 1 mCi 99mTc-hepatate for scintigraphy and 5 g lactulose for the H2-breath test. Scintigraphic scanning was performed for at least two hours, and gastric half-emptying time (T1/2) was calculated. Breath samples were collected at 15 minute intervals and analyzed for H2-enrichment. The orocecal transit time (OCTT) was then determined. A parameter of intestinal transit (PIT) was obtained by subtracting the T1/2 from the OCTT. RESULTS: There were no significant differences (in minutes) between the different tests in both T1/2 (0 g, t = 88.2 +/- 11, 2.5 g, t = 83.3 +/- 11.9, 3.5 g, t = 83.3 +/- 13.6, 4.5 g, t = 72.4 +/- 7.2, p = 0.86) and PIT (0 g, t = 149.9 +/- 26.6, 2.5 g, t = 145.5 +/- 25.6, t = 3.5 g, t = 175.3 +/- 17.6, t = 4.5 g, t = 152.6 +/- 22.4, p = 0.52). CONCLUSION: Addition of guar gum to a semisolid meal up to a dosage of 4.5 g does not affect gastrointestinal transit. Other mechanisms than gastrointestinal motility are involved in a possible satiating effect of guar gum supplementation.     

The effect of soluble- and insoluble-fibre supplementation on post-prandial glucose tolerance, insulin and gastric inhibitory polypeptide secretion in healthy subjects

Six healthy non-obese male subjects were given three test meals containing 100 g carbohydrate and 1.5 g soluble paracetamol, supplemented on one occasion with 10 g guar gum and on another with 10 g sugarbeet fiber. A further six subjects were given the same test meal supplemented on one occasion with 10 g soya-bean-cotyledon fibre and on another, 5 g glucomannan. Venous blood samples were taken before, and at intervals for 180 min following the meal, and analysed for insulin, gastric inhibitory polypeptide (GIP) and paracetamol (as an index of gastric emptying). Arterialized blood samples were taken and analysed for glucose. Meal supplementation with both guar gum and sugar-beet fibre improved glucose tolerance, but circulating glucose levels were unaffected by the addition of either soya-bean-cotyledon fibre or glucomannan to the meals. Supplementation with guar gum and glucomannan lowered post-prandial insulin levels. Insulin levels were enhanced by addition of soya-bean-cotyledon fibre to the meal and unaffected by sugar-beet fibre. Post-prandial GIP levels were lowered in the guar-gum-supplemented meal and augmented with sugar-beet fibre supplementation. Addition of glucomannan and soya-bean-cotyledon fibre did not affect circulating GIP levels. The study failed to confirm previous reports of improved glucose tolerance following glucomannan and soya-bean-cotyledon fibre supplementation. The failure of sugar-beet fibre to reduce post-prandial insulin secretion despite improved glucose tolerance may be due to the observed increased secretion of GIP. The increased insulin levels seen following soya-bean-cotyledon fibre supplementation cannot be attributed either to changes in glucose tolerance, GIP secretion or gastric emptying.(ABSTRACT TRUNCATED AT 250 WORDS)     

Sucrose-induced insulin resistance in the rat: modulation by exercise and diet

Isocaloric substitution of sucrose for starch results in hyperinsulinemia and deterioration of glucose tolerance, suggesting a loss of insulin sensitivity. In this study we have quantitated the insulin resistance which develops with sucrose feeding, and evaluated the ability of dietary fiber, or an increase in skeletal muscle activity, to inhibit, or even prevent, the detrimental effect of sucrose feeding on in vivo insulin action. Thus, 6-wk-old rats were fed one of the following regimens for three weeks: a 64% cornstarch diet (C), a 32% cornstarch + 32% sucrose diet (S), the (S) diet containing added wheat bran fiber (S/F), and the (S) diet given to rats running spontaneously in exercise wheel cages (S/ET). Insulin sensitivity was evaluated by comparing steady-state plasma glucose (SSPG) concentrations at constant plasma insulin levels approximately 70 microU/ml attained during the continuous infusion of epinephrine (0.08 micrograms/kg/min), propranolol (1.7 micrograms/kg/min), glucose (8 mg/kg/min), and insulin (2.5 mU/kg/min) to each experimental group. The results show that rats fed the S diet had a significant increase (p less than 0.01) in mean (+/- SEM) SSPG concentration compared with rats fed the C diet (255 +/- 14 versus 165 +/- 3 mg/dl). SSPG concentrations, although lower (p less than 0.05) in rats fed S/F (205 +/- 8 mg/dl), were still higher (p less than 0.05) than the C levels (165 +/- 3 mg/dl). However, S/ET completely inhibited the increase in SSPG concentration seen in rats fed S and the values were actually lower (p less than 0.05) than in rats fed C (100 +/- 10 versus 165 +/- 3 mg/dl). In conclusion 1) sucrose feeding results in a loss of insulin sensitivity in normal rats; 2) addition of fiber attenuates, but does not completely prevent, the loss of insulin sensitivity associated with feeding sucrose; 3) exercise training prevents the loss of insulin sensitivity seen in sucrose-fed rats, and actually improves glucose uptake beyond that seen in the control group. These results document the profound effect of environmental factors on in vivo insulin action.     

Fiber supplementation results in expanded proliferative zones in rat gastric mucosa

The effects of three different fibers on gastric fundic mucosal morphometrics and cytokinetics were compared by feeding defined diets to 40 male Sprague-Dawley rats for 4 wk. Groups of 10 rats each were fed a fiber-free diet as a control or the same diet uniformly diluted with either 20% oat bran, 10% pectin, or 10% guar. Fiber supplementation expanded the zone of proliferating cells by 58% with the guar-supplemented diet (p less than 0.05), 101% with oat bran (p less than 0.05), and 150% with pectin (p less than 0.01) compared with controls. Expansion was due to a downward shift in proliferating cells towards the muscularis mucosa of the oat bran and pectin groups (p less than 0.01) while pectin also expanded the proliferative zone toward the mucosal surface (p less than 0.05). Because expanded proliferative zones have been shown to precede and accompany neoplastic transformation, these data suggest a potentially negative effect of dietary fiber on the gastric mucosa.     

Effect of various types of dietary fibre on gastric emptying in growing pigs

1. Five pigs initially of 40-50 kg live weight were fitted with simple gastric cannulas which permitted complete evacuation and sampling of gastric digesta once daily. 2. The effects of addition of four types of dietary fibre (wheat bran (WB; 40 g/kg), sodium carboxymethylcellulose (CMC; 40 g/kg), high-methoxy citrus pectin (Pe; 40 g/kg) and granulated guar gum (G; 40 g/kg] on gastric emptying of a semi-purified diet during 4 h following a meal were measured. 3. Each of the test diets and the control diet (C) were given to each pig for 1 week using a 5 x 5 Latin-square arrangement. Digesta were collected before and 0.5, 1, 2 or 4 h after feeding on the last 5 d of each week. 4. The mean gastric pH was not significantly affected by diet except 2 h after feeding (CMC higher than C) and 4 h (Pe, G and CMC higher than C). 5. Compared with diet C, the rate of gastric emptying of digesta was significantly slower for diet G, 1, 2 and 4 h after feeding, and 2 and 4 h after feeding for diet CMC. 6. The rates of gastric emptying of digesta components were not significantly reduced by dietary fibre except for dry matter (DM) (diet CMC 2 h and diet B 4 h after feeding), total nitrogen (TN) (diet G 2 h after feeding) and total glucose (diet Pe 2 h after feeding). 7. There were no significant effects of diet on trichloroacetic-acid-soluble N:TN. 8. When gastric emptying was expressed in terms of half-time (T50) values, significant increases (compared with diet C) were found for digesta (diets G and CMC), DM (diet WB) and TN (diet G). 9. The apparent viscosity of the gastric digesta was significantly higher when diets Pe, G, and CMC were given than diets C or WB. Diets Pe and CMC were very viscous in the meal before ingestion, but diet G was not; its high viscosity developed after it had reached the stomach. 10. It is concluded that although those types of dietary fibre which increased meal or gastric viscosity reduced the rate of gastric emptying of digesta, this effect was confined to the liquid phase, because DM, total glucose and TN emptying were largely unaffected. The hypothesis that a reduced rate of gastric emptying may be an important determinant of the decreased rates of glucose absorption observed when such sources of dietary fibre are eaten is not supported by the results presented.     

Effect of guar gum on gastric emptying of test meals of varying energy content in growing pigs

1. Existing information on whether the action of guar gum in decreasing postprandial blood glucose concentrations is due, at least in part, to a reduced rate of gastric emptying is conflicting, possibly because three types of test meals have been used. In order to test whether the type of test meal used influences the action of guar gum, these three types of meal were compared, either without or with guar gum, in growing pigs. The meals were: a high-energy meal (HEM), a low-energy milky drink (LEMD) and a glucose drink (GD). 2. Six pigs were prepared with a simple gastric cannula which allowed complete removal of the stomach contents just before or 0.5, 1, 2 or 4 h after feeding. 3. The three types of test meal without guar gum gave rise to very different postprandial profiles of gastric pH and of digesta and dry matter (DM) emptying from the stomach. 4. Addition of guar gum to the GD significantly raised gastric pH at 0.5 and 1 h after feeding but, when it was added to HEM, gastric pH was only significantly raised 4 h after feeding. No significant effect on gastric pH was seen when guar gum was added to LEMD. 5. Although addition of guar gum to GD had no significant effect on the emptying of digesta from the stomach, when added to HEM the rate of emptying of digesta was significantly reduced 1, 2 and 4 h after feeding. Addition of guar gum to LEMD only significantly increased the amount of digesta remaining in the stomach 2 h after feeding. 6. There was no significant effect on the emptying of DM from the stomach when guar gum was added to either HEM or LEMD. However, addition of guar gum to GD significantly reduced the mean rate of emptying of DM 0.5 h after feeding. 7. Addition of guar gum to either LEMD or GD had no significant effect on the DM concentration of the evacuated gastric digesta. However, addition of guar gum to HEM significantly lowered the DM concentration of the evacuated gastric digesta 1, 2 and 4 h after feeding. 8. It was concluded that differences in test meal composition and also in the methods used to measure gastric emptying could account for the discrepancies previously reported. The results suggest that although guar gum may reduce the rate of gastric emptying under some conditions, this is unlikely to be the only mechanism by which it acts.     

The effect of guar gum and level and source of dietary fat on glucose tolerance in growing pigs

Six growing pigs (30-75 kg) were fed on semi-purified diets containing either 30 g maize oil/kg diet (LFM), 30 g soya-bean oil-tallow mixture (1:1, w/w)/kg diet (LFST) or 160 g soya-bean oil-tallow mixture (1:1, w/w)/kg diet (HFST) without and with the addition of guar gum (40 g/kg diet). Plasma glucose and insulin concentrations following twice daily feeding at 09.00 and 21.00 h were measured, during 24 h periods, in blood sampled from a permanent indwelling vena cava catheter. The source and level of dietary fat had no significant effect on pre-prandial plasma glucose or insulin concentrations except for insulin with diet LFST in the morning (P less than 0.05). Addition of guar gum to the diets had no significant effect on pre-prandial plasma glucose and insulin levels. The peak post-prandial plasma glucose and insulin levels were not significantly affected by dietary fat. The addition of guar gum, however, significantly reduced (P less than 0.05) the peak post-prandial plasma glucose concentration with diets LFM and LFST and also the peak plasma insulin concentration for all diets except for diet HFST in the morning. The time taken to reach the peak post-prandial plasma glucose and insulin concentrations was not significantly affected by dietary fat but it was increased by the addition of guar gum, although the differences were not always significant.     

Dietary guar gum effects on postprandial blood glucose, insulin and hydroxyproline in humans

Meals (425 kcal) containing various doses of guar gum (0, 2.5, 7.5 or 12.5 g) were ingested by nine healthy male subjects after a 12-h fast. The rise in blood glucose was higher after the control meal without guar gum than after the guar gum-containing meals, which all gave a similar rise in glucose. In contrast, increased doses of guar gum led to a greater reduction in the postprandial rise in insulin. The postprandial increase in serum hydroxyproline, an amino acid added to all meals, was decreased in a similar manner by all of the guar gum doses. Gastric emptying was measured after the control meal without guar gum and the meal containing 12.5 g of guar gum by monitoring 51Cr, which was added to the meals. Guar gum was found to reduce the variation between individuals, as well as the initial rate of gastric emptying, which correlated with changes in both serum hydroxyproline (rs = 0.93, P less than 0.01) and blood glucose (rs = 0.83, P less than 0.01). The effectiveness of guar gum in reducing postprandial response was lost after heating and homogenization for canning. A threshold in the reduction in rise of glucose or hydroxyproline was reached with the lowest dose (2.5 g) of viscous guar gum; larger doses had no additional effects. The reduced absorption seems to be an effect of a slower gastric emptying rate.     

Effects of high fiber breakfasts on glucose metabolism in noninsulin-dependent diabetics

This study investigated dietary fiber in noninsulin-dependent diabetics, the major North American diabetic population, using modest fiber increases as a strategy to promote dietary adherence. Once weekly over a 3-wk period, five lean, diet-controlled noninsulin-dependent diabetics ingested one of three isocaloric, isocarbohydrate breakfasts (337 kcal, 49 g carbohydrate), differing primarily in dietary fiber: 3 g bran (control), 17 g bran (B), or 18 g bran and fruit (BF). B and BF were higher in protein than control; BF contained more sugar than B and control. Compared to control, B reduced (p less than 0.05) plasma glucose over 180 min; BF did not. The peak blood glucose rise after BF was lower than control (p less than 0.01) whereas no effect was seen with B. B reduced xylose absorption (p less than 0.025) suggesting a reduced rate of glucose absorption; BF did not. Insulin, growth hormone, and glucagon values did not differ. This study suggests significant plasma glucose reductions with bran or bran and whole apple; other nutrient differences (higher protein in fiber meals, higher sugar with whole apple meal) might also be related. Further research is indicated to clarify these responses and extend the data to obese noninsulin-dependent diabetics.     

Oat-bran cereal lowers serum total and LDL cholesterol in hypercholesterolemic men

Oat bran lowers serum lipid concentrations in healthy and hyperlipidemic subjects. To determine the effects of a ready-to-eat oat-bran cereal on lipid concentrations, we fed control (corn flakes) and oat-bran cereal diets for 2 wk to 12 men with undesirably high serum total-cholesterol concentrations. Subjects were randomly assigned to one of the two diets upon admission to the metabolic ward. After completing the first diet, subjects completed 2 wk on the alternate diet. Intakes of carbohydrate, protein, fat, and cholesterol were virtually identical on the two diets. The oat-bran cereal provided 25 g oat bran/d. The oat-bran cereal diet compared with the corn flakes diet lowered serum total-cholesterol and serum LDL-cholesterol concentrations significantly by 5.4% (p less than 0.05) and 8.5% (p less than 0.025), respectively. Final body weights on each of the diets were similar. Ready-to-eat oat-bran cereal provides a practical means to incorporate soluble fiber into the diet to lower serum cholesterol.     

Long-term effects of fermentable fibers on rat colonic pH and epithelial cell cycle

The long-term effects of fermentable fibers on colonic luminal pH and the epithelial cell cycle were compared in 50 male Sprague-Dawley rats fed either a defined basal fiber-free diet or the basal diet supplemented with 10% pectin, cellulose or guar or with 20% oat bran. After 8 mo, in vivo pH measurements revealed that acidification of luminal contents occurred in the cecum and in mid and distal colons of rats fed fiber-supplemented diets when compared with the fiber-free controls (P less than 0.05). Pectin and guar produced the greatest acidification of luminal contents, the largest increase in cecal surface area and the highest percentage of colonic cells in S-phase, as measured by flow cytometry. In the proximal colon of the pectin group 9.2 +/- 0.5% of cells were in S-phase (6.3 +/- 0.8% with the fiber-free group) (P less than 0.05) and in the distal colon of the guar group 10.9 +/- 1.4% were in S-phase (7.1 +/- 0.5% with the fiber-free group) (P less than 0.05). Even though the most fermentable fibers produced the greatest mitogenic response, there was no site-specific correlation between pH and mucosal cell growth except in the cecum. This suggests that fibers may act as colon cell growth factors by some mechanism other than extracellular pH changes.     

A simple isotope method for studying of gastric emptying of solid foods

A simple isotope method is explained by the authors for noninvasive functional evaluation of the gastric emptying of solid meal. According to the results of in vitro measurements suitable solid phase labelling was provided by boiling the egg traced with injected Tc-99m-pertechnetate. The evaluation of gastric emptying by means of test meal containing the radiolabelled boiled egg is simple, inexpensive and the radiation hazard is minimal. In cases of intact stomach the gastric emptying of solids (T2 = 115.1 +/- 12.4 min) were significantly slower, than in cases of Billroth I (T2 : 66.7 +/- 6.9 min, p less than 0.01) and Billroth II (T2 = 28.8 +/- 3.3 min, p less than 0.001) resections. Similarly, there was a significant difference (p less than 0.001) between the mean half time values of the two operated groups.