No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Abstract
The aim of this study was to compare the effects of two nondigested, nonabsorbed dietary components on objective and subjective measures of gastrointestinal (GI) function.
A placebo-controlled parallel study compared the effects of wheat bran (20 g/day or 40 g/day in cereal), a well-known dietary fiber, with those of olestra (20 g or 40 g/day in potato chips), a nonabsorbed fat, on stool output, stool apparent viscosity (log peak force for extrusion [PF]), stool water content, and GI symptoms. Sixty subjects resided on a metabolic ward for 9 days: 3 days baseline and 6 days treatment.
Compared with placebo, consumption of 20 g/day wheat bran for 6 days resulted in a rapid (within 38 h) increase in mean (+/-SE) stool output (placebo, 150 +/- 29 g/day; bran, 246 +/- 35 g/day, p < 0.05), a directional increase in mean stool water content (placebo, 81.2 +/- 0.8%; bran, 83.9 +/- 0.8%), stool water output (placebo, 159 +/- 54 g/day; bran, 238 +/- 30 g/day), and bowel movement frequency (BM/day) (placebo, 2.2 +/- 0.4; bran, 2.6 +/- 0.4), and no stool-softening effect (placebo log PF, 2.9 +/- 0.1 g; bran log PF, 2.9 +/- 0.1 g). Wheat bran 40 g/day results were not significantly different from wheat bran 20 g/day. Compared with placebo, consumption of olestra 20 g/day and 40 g/day for 6 days showed no significant difference in mean stool output (151 +/- 18 g/day and 204 +/- 28 g/day, respectively), mean BM frequency (1.8 +/- 0.2 BM/day and 2.1 +/- 0.3 BM/day, respectively), and stool water output (138 +/- 13 g/day and 184 +/- 31 g/day, respectively), a significant (p < 0.05) decrease in stool water content (75.5 +/- 1.7% and 72.6 +/- 2.2%, respectively), and either no effect on stool apparent viscosity (olestra 20 g/day, mean log PF, 3.0 +/- 0.1 g) or a gradual stool-softening effect beginning study day 6 (olestra 40 g/day, log PF, 2.7 +/- 0.1 g). None of the treatment groups showed a significant increase in GI symptoms compared with placebo.
Consumption of wheat bran in excess of levels in a typical Western diet significantly increased stool output, but did not soften normal-viscosity stool nor result in an increase in common GI symptoms. The observed plateau effect for wheat bran at 40 g/day suggests a maximal mechanical stimulatory effect. Consumption of olestra in excess of usual snacking conditions did not result in a significant increase in stool output or common GI symptoms. At the highest level tested, olestra resulted in a gradual stool-softening effect after several days of consumption.
... In contrast to insoluble fibers, soluble viscous fibers (e.g., psyllium) have a high water-holding capacity, are relatively nonfermentable, and form a gel that resists dehydration in the colon (Lewis & Heaton, 1999;McRorie, Pepple, & Rudolph, 1998). Consumption of a gel-forming, nonfermentable fiber (e.g., psyllium) results in the dose-related formation of highmoisture, soft, bulky stools (Lewis & Heaton, 1999;Marlett, Kajs, & Fischer, 2000;McRorie, Daggy, et al., 1998;McRorie, Pepple, et al., 1998 ) without increasing gas production or flatulence (Levitt, Furne, & Olsson, 1996;McRorie, Kesler, et al., 2000). Further, psyllium has a high water-holding capacity that can normalize stool consistency, with a paradoxical ability to soften stool in constipated patients while improving stool consistency in those with diarrhea (Singh, 2007;Zumarraga, Levitt, & Suarez, 1997). ...
... Gas: The sensation of "gas" can be replicated with balloon inflation in the gut and is as a result of bowel wall distention; thus, it may have little to do with the presence of "gas" (Levitt et al., 1996;McRorie, Kesler, et al., 2000). Gas present in the gut is either absorbed into the blood stream and eliminated via the lungs, hence, the "breath gas analysis" for fermentation byproducts, or it is eliminated via flatulence. ...
... Gas present in the gut is either absorbed into the blood stream and eliminated via the lungs, hence, the "breath gas analysis" for fermentation byproducts, or it is eliminated via flatulence. Fibers that are rapidly fermented can outpace the gut's ability to absorb gas into the blood stream, resulting in increased flatulence, whereas fibers that exhibit very limited, slow fermentation do not cause excess flatulence (Levitt et al., 1996;McRorie, Kesler, et al., 2000). Fermentation of soluble nonviscous fibers can result in rapid gas production, leading to increased flatulence (Bianchi & Capurso, 2002;Eherer et al., 1993). ...
Purpose: This review focuses on the health benefits of viscous versus nonvis-cous soluble fibers, why symptoms can occur with increased fiber consumption , and how to avoid symptoms to improve adherence with a high-fiber diet.
... In contrast to insoluble fibers, soluble viscous fibers (e.g., psyllium) have a high water-holding capacity, are relatively nonfermentable, and form a gel that resists dehydration in the colon (Lewis & Heaton, 1999;McRorie, Pepple, & Rudolph, 1998). Consumption of a gel-forming, nonfermentable fiber (e.g., psyllium) results in the dose-related formation of highmoisture, soft, bulky stools (Lewis & Heaton, 1999;Marlett, Kajs, & Fischer, 2000;McRorie, Daggy, et al., 1998;McRorie, Pepple, et al., 1998 ) without increasing gas production or flatulence (Levitt, Furne, & Olsson, 1996;McRorie, Kesler, et al., 2000). Further, psyllium has a high water-holding capacity that can normalize stool consistency, with a paradoxical ability to soften stool in constipated patients while improving stool consistency in those with diarrhea (Singh, 2007;Zumarraga, Levitt, & Suarez, 1997). ...
... Gas: The sensation of "gas" can be replicated with balloon inflation in the gut and is as a result of bowel wall distention; thus, it may have little to do with the presence of "gas" (Levitt et al., 1996;McRorie, Kesler, et al., 2000). Gas present in the gut is either absorbed into the blood stream and eliminated via the lungs, hence, the "breath gas analysis" for fermentation byproducts, or it is eliminated via flatulence. ...
... Gas present in the gut is either absorbed into the blood stream and eliminated via the lungs, hence, the "breath gas analysis" for fermentation byproducts, or it is eliminated via flatulence. Fibers that are rapidly fermented can outpace the gut's ability to absorb gas into the blood stream, resulting in increased flatulence, whereas fibers that exhibit very limited, slow fermentation do not cause excess flatulence (Levitt et al., 1996;McRorie, Kesler, et al., 2000). Fermentation of soluble nonviscous fibers can result in rapid gas production, leading to increased flatulence (Bianchi & Capurso, 2002;Eherer et al., 1993). ...
This review focuses on the health benefits of viscous versus nonviscous soluble fibers, why symptoms can occur with increased fiber consumption, and how to avoid symptoms to improve adherence with a high-fiber diet.
Review of scientific literature as well as evidence-based guidelines and resources.
While it is generally known that "fiber is good for you," it is less well known that specific health benefits are associated with specific fiber characteristics. Many of the health benefits of fiber can be directly correlated with the viscosity of soluble fibers when hydrated (i.e., gel-forming). A reduction in viscosity of a given fiber will attenuate these health benefits, and a nonviscous fiber does not exhibit these health benefits.
Increasing the viscosity of chyme with a viscous soluble fiber has been shown clinically to lower cholesterol for cardiovascular health, improve glycemic control in type 2 diabetes, normalize stool form in both constipation (softens hard stool) and diarrhea (firms loose/liquid stool), and improve the objective clinical measures of metabolic syndrome (glycemic control, lipoprotein profile, body mass index/weight loss, and blood pressure).
... Auch bei Patienten vom Diarrhoe-Typ können Ballaststoffe erfolgreich eingesetzt werden [522,524,525]. Brot hat keinen anhaltenden positiven Effekt [526,527]. In einem kleinen RCT konnte gezeigt werden, dass Psyllium (2 × 3,4 g) und Methylcellulose (2 × 2 g) keine vermehrte Gasproduktion bewirken [528]. ...
... Auch bei Patienten vom Diarrhoe-Typ können Ballaststoffe erfolgreich eingesetzt werden [522,524,525]. Brot hat keinen anhaltenden positiven Effekt [526,527]. In einem kleinen RCT konnte gezeigt werden, dass Psyllium (2 × 3,4 g) und Methylcellulose (2 × 2 g) keine vermehrte Gasproduktion bewirken [528]. ...
... Stanyon and Costello (1990) used wheat bran to enhance the nutritional quality of baked products such as cakes, yeast bread and muffins. McRorie et al. (2000) reported that consumption of wheat bran in excess of levels in a typical western diet significantly increased stool output. Malkki (2001) reported that the physiological effects of dietary fiber are usually compared with the intakes or contents of total dietary fiber. ...
Three local sudanese wheat cultivars, Debeira, El-Nielain and Sasaraib were obtained from Agricultural Research Corporation (harvest season 2002/03). Wheat bran was obtained from a local flour mill in Khartoum North. It was carefully sieved and classified as coarse, medium and fine bran size then fermented. Proximate composition, mineral content and anti-nutritional factors (tannin, phytic acid) were determined for all types of wheat bran. Results indicated that fermentation of wheat bran increased the percentage of crude fiber from 15.67 to 18.67%, 15.67 to 18.00%, 15.00 to 17.67%, protein content from 20.35 to 21.65%, 18.36 to 20.79%, 21.07 to 22.40% for coarse, medium and fine wheat brans, respectively. Carbohydrates percentage increased from 45.09 to 47.4% in fermented coarse wheat bran. Both anti-nutritional factors (tannins and phytic acid) were found to decrease significantly (P<0.05) in coarse, medium and fine wheat bran. The tannin content decreased from 0.03 to 0.01, 0.07 to 0.05 and from 0.07 to 0.06 mg catechin/100 gm, respectively. Phytic acid decreased from 626.1 to 572.8, 740.4 to 367.1 and from 795.2 to 301.6 mg/100 gm, respectively. There is no change on the values of Ca and Fe contents of coarse wheat bran after fermentation. Also there was an increase in Ca content of fine and medium wheat bran. Fe content of medium wheat bran decreased from 0.03 to 0.02% but Fe content of fine wheat bran increased from 0.023 to 0.033%. There is a slight decrease in P content of coarse wheat bran after fermentation. The phosphorous content as percentage decreased in fermented medium and fine wheat bran from 0.004 and 0.003% to 0.002 and .002%, respectively. Bread specific volume values of the three cultivars with 10, 15 and 20% fermented wheat bran decreased with increase in the amount of wheat bran. Bread with 10% fermented coarse wheat bran gave the best results for all characteristics tested in organolyptic evaluation.
... This decrease in stool water content is consistent with reports from the healthy subjects of difficult/uncomfortable bowel movements during the fine wheat bran treatment period (constipating effect) [55]. There appears to be a limit to the mechanical stimulatory effect of insoluble fiber in that consumption of 20 g/day wheat bran for 6 days resulted in a rapid (within 38 h) increase in mean stool output (150 g/day with placebo, 246 g/day with bran, p \ 0.05), yet consumption of wheat bran 40 g/day did not increase stool output above that observed with the 20 g/day dose [56]. ...
Background
Misconceptions about the effects of dietary fiber and ?functional? fiber on stool parameters and constipation persist in the literature. MethodsA comprehensive literature review was conducted with the use of the Scopus and PubMed scientific databases to identify and objectively assess well-controlled clinical studies that evaluated the effects of fiber on stool parameters and constipation. ResultsThe totality of well-controlled randomized clinical studies show that, to exert a laxative effect, fiber must: (1) resist fermentation to remain intact throughout the large bowel and present in stool, and (2) significantly increase stool water content and stool output, resulting in soft/bulky/easy-to-pass stools. Poorly fermented insoluble fiber (e.g., wheat bran) remains as discreet particles which can mechanically irritate the gut mucosa, stimulating water & mucous secretion if the particles are sufficiently large/coarse. For soluble fibers, some have no effect on viscosity (e.g., inulin, wheat dextrin) while others form high viscosity gels (e.g., ?-glucan, psyllium). If the soluble fiber is readily fermented, whether non-viscous or gel-forming, it has no effect on stool output or stool water content, and has no laxative effect. In contrast, a non-fermented, gel-forming soluble fiber (e.g., psyllium) retains its gelled nature and high water-holding capacity throughout the large bowel, resulting in soft/bulky/easy-to-pass stools. Conclusion
When considering a recommendation for a fiber supplement regimen to treat and/or prevent constipation, it is important to consider which fibers have the physical characteristics to exert a laxative effect, and which fiber supplements have rigorous clinical evidence of a significant benefit in patients with constipation.
... The geographical location and human development index ranking of studies used in statistical analysis (Continued) Country n HDI * References USA 18 1 Canfield et al. (1963), Watts et al. (1963), Diem and Lentner (1970), Goldsmith and Burkitt (1975), Cummings et al. (1978), Glober et al. (1977), Goldberg et al. (1977), Beyer and Flynn (1978), Reddy et al. (1978), Calloway and Kretsch (1978), Kien et al. (1981), Polprasert and Valencia (1981), Tucker et al. (1981), Schubert et al. (1984), Parker and Gallagher (1988), Zuckerman, et al. (1995), Aichbichler et al. (1998), McRorie et al. (2000) 3. RESULTS ...
The safe disposal of human excreta is of paramount importance for the health and welfare of populations living in low income countries as well as the prevention of pollution to the surrounding environment. On site sanitation (OSS) systems are the most numerous means of treating excreta in low income countries, these facilities aim at treating human waste at source and can provide a hygienic and affordable method of waste disposal. However, current OSS systems need improvement and require further research and development. Development of OSS facilities that treat excreta at, or close to, its source require knowledge of the waste stream entering the system. Data regarding the generation rate and the chemical and physical composition of fresh faeces and urine was collected from the medical literature as well as the treatability sector. The data were summarised and statistical analysis was used to quantify the major factors that were a significant cause of variability. The impact of this data on biological processes, thermal processes, physical separators and chemical processes was then assessed. Results showed that the median faecal wet mass production was 128 g/cap/day, with a median dry mass of 29 g/cap/day. Faecal output in healthy individuals was 1.20 defecations per 24 hour period and the main factor affecting faecal mass was the fibre intake of the population. Faecal wet mass values were increased by a factor of 2 in low income countries (high fibre intakes) in comparison to values found in high income countries (low fibre intakes). Faeces had a median pH of 6.64 and were composed of 74.6% water. Bacterial biomass is the major component (25-54% of dry solids) of the organic fraction of the faeces. Undigested carbohydrate, fibre, protein and fat comprise the remainder and the amounts depend on diet and diarrhoea prevalence in the population. The inorganic component of the faeces is primarily undigested dietary elements that also depend on dietary supply. Median urine generation rates were 1.42 litres/cap/day with a dry solids content of 59 g/cap/day. Variation in the volume and composition of urine is caused by differences in physical exertion, environmental conditions as well as water, salt and high protein intakes. Urine has a pH 6.2 and contains the largest fractions of nitrogen, phosphorus and potassium released from the body. The urinary excretion of nitrogen was significant (10.98 g/cap/day) with urea the most predominant constituent making up over 50% of total organic solids. The dietary intake of food and fluid is the major cause of variation in both the faecal and urine composition and these variables should always be considered if the generation rate, physical and chemical composition of faeces and urine is to be accurately predicted.
... Uczucie dyskomfortu i wzdęcie są jednymi z najczęściej podnoszonych argumentów przeciwników diety bogatoresztkowej wśród laików -mimo, że nie znalazły potwierdzenia w badaniach (38). Zwiększone wytwarzanie gazów jelitowych, będących wynikiem bakteryjnej fermentacji w jelicie grubym, staję się dokuczliwe przy nagłym zwiększeniu ilości błonnika w diecie. ...
Błonnik to grupa heterogennych substancji - węglowodanów nieulegających trawieniu i wchłonięciu w przewodzie pokarmowym człowieka, w skład której wchodzą błonnik pokarmowy i suplementarny. Błonnik pokarmowy to nieuszkodzone węglowodany i ligniny pochodzenia roślinnego naturalnie zawarte w pożywieniu, natomiast błonnik suplementarny to syntetycznie wyizolowane węglowodany, które mają korzystny wpływ na zdrowie i jakość życia człowieka. Optymalna dobowa podaż błonnika to 14 g/1000 kcal u dzieci powyżej 1 r.ż. Stosowanie tak zbilansowanej diety może zapobiegać zaparciu, otyłości oraz cukrzycy, a w wieku późniejszym skutkować zmniejszeniem ryzyka chorób układu sercowo-naczyniowego i nowotworów. Stopniowe zwiększanie zawartości błonnika minimalizuje ryzyko działań niepożądanych i nie prowadzi do zaburzeń wchłaniania. Problem stosowania diety bogatoresztkowej u najmłodszych dzieci oraz suplementacja błonnika pozostają kwestią otwartą i wymagają dalszych badań.
... Rather it caused a gradual stool softening effect after several days' consumption. (25) It was reported that olestra fed to mini pigs (80 g/d) resulted in softening of stool but did not affect wet weight of stool or colonic transit time. (26) However, in a case study of a 16-year old girl with hypercholesterolemia and hypertension, it was reported that concurrent use of olestra with orlistat (a drug that blocks the action of lipase and prevents digestion and absorption of dietary fat) caused the subject to suffer from soft, fatty/oily stools, flatus with discharge, abdominal pain, increased flatus, and fecal incontinence, but such gastrointestinal effects were substantially reduced with orlistat treatment alone. ...
Olestra is a sucrose polyester, the first fat substitute that replaces many of the uses of dietary fat such as in dough conditioning, in sprays, in filling ingredients, in flavors, as well as in frying. However, it is not absorbed in the human digestive system, and therefore, it does not provide any nutrition or energy. It has taste and cooking properties similar to the conventional fats and oils. FDA approved the use of olestra only in limited and specific foods with a listing of fat soluble vitamins (vitamins A, D, E, and K) in the ingredient statement of olestra-containing foods followed by an asterisk that is linked to the statement “Dietarily insignificant.” This article reviews the physiological, nutritional, health, and environmental effects of the human consumption of olestra.
... Auch bei Patienten mit Schmerz/Bläh-und Diarrhö-Typ können Ballaststoffe erfolgreich eingesetzt werden [403,404]. Brot hat keinen anhaltenden positiven Effekt [405,406]. In einer kleinen RCT konnte gezeigt werden, dass Psyllium (2 × 3,4 g) und Methylcellulose (2 × 2 g) keine vermehrte Gasproduktion bewirken [407]. ...
... Auch bei Patienten mit Schmerz/Bläh-und Diarrhö-Typ können Ballaststoffe erfolgreich eingesetzt werden [403,404]. Brot hat keinen anhaltenden positiven Effekt [405,406]. In einer kleinen RCT konnte gezeigt werden, dass Psyllium (2 × 3,4 g) und Methylcellulose (2 × 2 g) keine vermehrte Gasproduktion bewirken [407]. ...
... Auch bei Patienten mit Schmerz/Bläh-und Diarrhö-Typ können Ballaststoffe erfolgreich eingesetzt werden [403,404]. Brot hat keinen anhaltenden positiven Effekt [405,406]. In einer kleinen RCT konnte gezeigt werden, dass Psyllium (2 × 3,4 g) und Methylcellulose (2 × 2 g) keine vermehrte Gasproduktion bewirken [407]. ...
... There are limited studies to suggest that chronic high intakes of dietary fiber can cause gastrointestinal distress. The ingestion of wheat bran at levels up to 40 g/day did not result in significant increases in GI distress compared to placebo [19]. However, flatulence did increase with increased intake of dietary fiber in general [20], and with gums that led to moderate to severe degrees of flatulence in a trial in which 4 to 12 g/day of a hydrolyzed guar gum were provided to 16 elderly patients [21]. ...
The relationship of dietary fiber to overall health is of great importance, as beneficial effects have been demonstrated with the use of fiber from diverse sources, some traditional, other novel. PolyGlycopleX (PGX) is a unique proprietary product composed of three water-soluble polysaccharides, that when processed using novel technology give rise to a final product - a soluble, highly viscous functional fiber.
Because of its potential use in food and dietary supplements, a randomized, double-blind, placebo controlled clinical study was conducted to evaluate the tolerance to PGX ingestion for 21 days, to a maximum dose level of 10 g per day, in healthy male and female volunteers. The main objective of the study was to evaluate the overall gastrointestinal (GI) tolerance, while secondary objectives were to evaluate possible changes in hematological, biochemical, urinary and fecal parameters.
Results show that PGX is well tolerated as part of a regular diet with only mild to moderate adverse effects, similar to those seen with a moderate intake of dietary fiber in general, and fruits and vegetables. Because PGX is a highly viscous, functional fiber, it also demonstrates several physiological responses including, but not limited to maintaining healthy total and LDL cholesterol and uric acid levels.
... Digestion of grains and starches reduces ammonia produced by fermentation of foods high in fat and sugar; this possibly prevents cell damage and reduces the risk of colon cancer (Govers, Gannon, Dunshea, Gibson, & Muir, 1999). Wheat bran has a tendency to cause flatulence and gastrointestinal discomfort; however, McRorie et al. (2000) found no gastrointestinal discomfort in a carefully controlled study with participants taking 20-40 g of wheat bran daily. This result also was found by Sauvaire et al. (1998). ...
To provide evidence-based research information about 47 herbs and natural products that have the potential to protect against the development of cancer.
Natural Medicines Comprehensive Database and Lawrence Review of Natural Products-Monograph System. Information about these herbs has been found in evidence-based studies cited in the references.
Early research shows that some herbs and natural products appear to have the potential to prevent cancer growth.
This preliminary evidence may be useful to healthcare professionals or patients who are concerned about cancer.
Oncology nurses who receive this information can become resources for patients or other healthcare professionals.
Objectif : Le but de cette étude était d’évaluer l’efficacité du son de blé dur riche en fibres alimentaires chez des patients adultes souffrant du syndrome de l’intestin irritable (SII).
Patients et méthodes : Il s’agit d’une étude prospective, incluant 40 patients soumis à un régime riche en son de blé (30 g/j). L’évaluation portait sur les critères cliniques (poids, nombre et consistance des selles) et l’évolution des différents symptômes : constipation, diarrhée, douleurs et ballonnements.
Résultats : Quarante patients ont été inclus (15 femmes et 25 hommes). L’âge moyen est de 45,35 ± 4,3 ans, 94,90 % vivaient en famille. Une consommation de 30 g/j de son de blé riche en fibres (43,5 % MS) a entraîné une augmentation très significative du poids des selles (200, 13 ± 24,23 vs 73,80 ± 15,96 g) [p < 0,001], de leur fréquence (1,80 ± 0,12 vs 1,07 ± 0,13 g) [p < 0,001] et une modification très significative de la consistance des selles dures des sujets constipés (p < 0,001). Une régularisation du transit intestinal : constipation (5 vs 70 %) et une amélioration des symptômes associés au transit digestif : douleurs (6,5 vs 60 %) et ballonnements (4,6 vs 45 %).
Conclusion : Cette étude démontre l’efficacité du son de blé dans le traitement du syndrome de l’intestin irritable.
Background: Constipation is a common public health concern experienced by all individuals during their life. It is an effective factor in the quality of life. In this paper, we aimed to provide an overview of the existing evidence regarding the role of food ingredients, including bran, prune, fig, kiwifruit, flaxseed, and olive on constipation treatment.
Scope and approach: We searched Scopus, PubMed, and ScienceDirect by using “laxative foods” and “constipation” for searching studies assessing laxative food ingredients and their beneficial effects on constipation treatment and/or control.
Key finding and conclusion: Lifestyle modifications such as increasing dietary fiber and fluid intake and regular daily exercise are in the first line of proposed treatments for constipation. Optimizing diet as an efficient lifestyle factor may contribute to the well-being of patients. The use of laxative food ingredients including bran, prune, fig, kiwifruit, flaxseed, probiotics, and prebiotics is a convenient alternative to laxatives to overcome constipation. According to the findings, laxative food ingredients could be considered as effective treatments for subjects suffering from constipation. Many studies have assessed the pharmacological and non-pharmacological roles of these ingredients in treating constipation; however, their importance has not been thoroughly investigated.
Background
Constipation is a common public health concern experienced by all individuals during their life. It is an affective factor on quality of life. In this paper, we aimed to provide an overview of the existing evidences regarding the role of food ingredients, including bran, prune, fig, kiwifruit, and flax-seed on constipation treatment.
Scope and approach
We searched Scopus, Pub Med, and Science Direct by using “laxative foods” and “constipation” for searching studies assessing laxative food ingredients and their beneficial effects on constipation treatment and/or control.
Key finding and conclusion
Lifestyle modifications such as increasing dietary fiber and fluid intake and regular daily exercise are in the first line of proposed treatments for constipation. Optimizing ‘diet’ as an efficient life style factor may contribute to the well-being of patients. The use of laxative food ingredients including bran, prune, fig, kiwifruit, flax-seed, probiotics, and prebiotics are convenient alternatives to laxatives to cope with constipation. According to findings, laxative food ingredients could be considered as effective treatments for subjects suffering from constipation. Many studies have assessed the pharmacological and non-pharmacological roles of these ingredients in treating constipation, however; their importance has not been thoroughly investigated.
Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder. It is widely believed that IBS is caused by a deficient intake of dietary fiber, and most physicians recommend that patients with IBS increase their intake of dietary fiber in order to relieve their symptoms. However, different types of dietary fiber exhibit marked differences in physical and chemical properties, and the associated health benefits are specific for each fiber type. Short-chain soluble and highly fermentable dietary fiber, such as oligosaccharides results in rapid gas production that can cause abdominal pain/discomfort, abdominal bloating/distension and flatulence in patients with IBS. By contrast, long-chain, intermediate viscous, soluble and moderately fermentable dietary fiber, such as psyllium results in a low gas production and the absence of the symptoms related to excessive gas production. The effects of type of fiber have been documented in the management of IBS, and it is known to improve the overall symptoms in patients with IBS. Dietary fiber acts on the gastrointestinal tract through several mechanisms, including increased fecal mass with mechanical stimulation/irritation of the colonic mucosa with increasing secretion and peristalsis, and the actions of fermentation byproducts, particularly short-chain fatty acids, on the intestinal microbiota, immune system and the neuroendocrine system of the gastrointestinal tract. Fiber supplementation, particularly psyllium, is both safe and effective in improving IBS symptoms globally. Dietary fiber also has other health benefits, such as lowering blood cholesterol levels, improving glycemic control and body weight management.
Fiber is a heterogenic group of nondigestible carbohydrates, which is the sum of dietary and functional fiber. Dietary fiber consists of carbohydrates and lignin that are intrinsic and intact in plants, while functional fiber consists of isolated carbohydrates that have beneficial physiological effects in humans. Adequate intake for fiber is 14 g/1000 kcal for children over 1 year. High fiber diet can prevent constipation, obesity and diabetes, and in later age reduces the risk of cardiovascular disease and cancer. Gradual increases in fiber intake decrease the risk of potential negative effects and do not lead to reduced absorption. The issues of fiber recommendations for younger children and fiber supplements require further research.
It has been almost 30 years since Coin proposed that computed tomography (CT) scanning had the potential to be used as a screening tool for the detection of colonic polyps [1]. Yet it was not until 1994 that Vining and coworkers were able to employ the new technology of spiral/helical CT and modern computer graphics, catalyzing extensive research and clinical efforts that molded the field that we now call CT colonography (CTC) or virtual colonoscopy. [2] Owing to these efforts, reasonable consensus now exists on the optimal means by which to prepare the patient, acquire the CT data, and interpret the resulting images, though some healthy debates do persist. The goal of this chapter is to describe these technical factors in CTC and to give the reader a perspective on current techniques and alternatives. We review the best evidence for current practices and recommendations. With this information, we hope the reader will have a thorough understanding of what is required to set up a high-quality clinical operation for performance of CTC. © Springer Science+Business Media New York 2013. All rights are reserved.
To comprehensively review and quantitatively summarize results from intervention studies that examined the effects of intact cereal dietary fiber on parameters of bowel function.
A systematic literature search was conducted using PubMed and EMBASE. Supplementary literature searches included screening reference lists from relevant studies and reviews. Eligible outcomes were stool wet and dry weight, percentage water in stools, stool frequency and consistency, and total transit time. Weighted regression analyses generated mean change (± SD) in these measures per g/d of dietary fiber.
Sixty-five intervention studies among generally healthy populations were identified. A quantitative examination of the effects of non-wheat sources of intact cereal dietary fibers was not possible due to an insufficient number of studies. Weighted regression analyses demonstrated that each extra g/d of wheat fiber increased total stool weight by 3.7 ± 0.09 g/d (P < 0.0001; 95%CI: 3.50-3.84), dry stool weight by 0.75 ± 0.03 g/d (P < 0.0001; 95%CI: 0.69-0.82), and stool frequency by 0.004 ± 0.002 times/d (P = 0.0346; 95%CI: 0.0003-0.0078). Transit time decreased by 0.78 ± 0.13 h per additional g/d (P < 0.0001; 95%CI: 0.53-1.04) of wheat fiber among those with an initial transit time greater than 48 h.
Wheat dietary fiber, and predominately wheat bran dietary fiber, improves measures of bowel function.
Constipation is a highly prevalent and difficult‐to‐cure health problem, forcing 10–20% of the worldwide population to seek medical care. Efficacy of treatments varies greatly among individuals, and problems are becoming more frequent despite higher consumption of fibre‐rich foods, the most popular solution for preventing such gastrointestinal disorders. The evidence that consumption of fibre prevents and relieves constipation is unconvincing or uncertain. The food industry has made great efforts to develop fibre‐rich ingredients, especially those from food by‐products and wastes. Except for psyllium and wheat bran, most of these ingredients have intermediate or low laxative potential and their efficacy needs to be confirmed by more clinical studies. This review suggests that there are major discrepancies between the proposed fibre‐enriched ingredients and the consumers' needs. As a lasting solution to prevent constipation, the true impact of dietary fibre and potent food‐grade laxatives might also be limited by overeating.
The purpose of this study was to determine whether a low-fiber diet is necessary for optimal tagging-only bowel preparation for CT colonography.
Fifty consecutively enrolled patients received an iodine bowel preparation: 25 patients used a low-fiber diet and 25 used no special diet. One observer determined the tagging quality per segment on a 5-point scale (1, inhomogeneous tagging; 5, excellent preparation) and the largest size of untagged feces. Semiautomatic measurements of density and homogeneity of residual feces were performed. Patient acceptance was assessed with questionnaires. Per polyp sensitivity for polyps 6 mm in diameter and larger was calculated for two experienced observers.
Tagging quality was scored less than grade 5 in 15 segments (10%) in the low-fiber diet group and in 25 segments (17%) in the unrestricted diet group (p = 0.098). One piece of untagged feces 10 mm in diameter or larger was found in the low-fiber diet group, and 12 were found in the unrestricted diet group (p < 0.001). Automatic measurement of attenuation resulted in a mean value of 594 HU in the low-fiber diet group and 630 HU in the unrestricted diet group (p = 0.297). In the low-fiber diet group, 22% of patients indicated that the bowel preparation was extremely or severely burdensome; 8% of patients in the unrestricted diet group had this response (p = 0.19). Thirty-two polyps 6 mm in diameter or larger were found in the low-fiber diet group and 30 in the unrestricted diet group. Observer 1 had 84% and 77% sensitivity in detecting polyps 6 mm in diameter or larger in the low-fiber diet and unrestricted diet groups, respectively (p = 0.443), and observer 2 had 97% and 83% sensitivity (p = 0.099).
Use of a low-fiber diet in bowel preparation for CT colonography results in significantly less untagged feces and shows a trend toward better residue homogeneity.
Market introduction of savory snacks containing olestra offered an opportunity to evaluate the safety of olestra in a free-living population and thereby compare the outcome to the previously established safety profile determined in clinical trials in which subjects were required to eat predetermined amounts at prescribed intervals. Therefore, a multifaceted postmarketing surveillance program was designed to evaluate consumer experience and safety of olestra in the marketplace. Customer comments were solicited through toll-free telephone numbers. Collected data were evaluated by both internal and external medical experts. About 10% of toll-free telephone calls reported health effects, most of which were gastrointestinal (GI) in nature. Clinical studies were designed and conducted to determine potential GI effects under the range of consumption patterns reported by toll-free calls. Health effects reported were those found commonly in the general population and analyses of the data found no biological reason to conclude that serious or meaningful health effects were the result of olestra consumption.
To report a case of significant additive gastrointestinal effects with concomitant use of orlistat and an olestra-containing snack food.
A 16-year-old African American girl with type 2 diabetes, hypercholesterolemia, and hypertension was participating in a pilot study that tested the safety and efficacy of orlistat. After 2 weeks of orlistat treatment, the patient presented to the clinic with complaints of soft, fatty/oily stools, flatus with discharge, abdominal pain, increased flatus, and fecal incontinence. On further questioning, it was determined that she was also consuming approximately 5 ounces of olestra-containing potato chips on a daily basis. The patient eliminated olestra from her diet and returned to the clinic with substantially diminished gastrointestinal adverse effects, despite continuing to take orlistat.
This is the first published case describing additive gastrointestinal effects after concurrent use of orlistat and olestra. Education about the potential for serious additive gastrointestinal adverse effects is important to prevent premature and unnecessary discontinuation of orlistat therapy. Awareness of this potential interaction could be especially important for patients with underlying disease states in which severe gastrointestinal symptoms could result in significant complications.
This case illustrates that significant gastrointestinal distress may result after olestra consumption during orlistat therapy. All patients receiving orlistat for the management of obesity should be properly educated about this potential drug-food interaction.
Olestra is a fat substitute made from fatty acids esterified to sucrose and can be used in the preparation of virtually any food made with fat. Foods made with olestra retain the mouthfeel, palatability and satiating effects of their full-fat counterparts without providing any digestible energy. Because olestra provides no energy, it has the potential to be a useful tool in weight loss and weight maintenance. Short-term studies of olestra replacement in foods demonstrate that fat replacement leads to a net reduction in fat intake. When excess total energy is available, fat replacement also reduces total energy intake in lean and obese men and women. In longer-term studies in which olestra is incorporated into the daily diet, there is an incomplete compensation for the fat energy replaced by olestra. When overweight men consumed olestra as part of a varied diet over nine months, weight loss continued for the duration of the study, whereas individuals receiving a typical low-fat diet regained most of the initial weight lost. Other studies are underway to examine the usefulness of olestra in long-term weight maintenance following weight loss. Post-marketing surveillance of olestra foods in the United States indicates that substitution of olestra for only 1-2 g of fat d-1 may be sufficient to prevent the average weight gain reported in adults of 0.5-1.0 kg year-1.
Recent evidence associates inflammatory mediators with coronary heart disease. Elevation of acute-phase reaction (APR) proteins such as serum amyloid A, fibrinogen, CRP and haptoglobin in response to Helicobacter pylori (H. pylori) infection was shown to initiate gastritis and ischemic heart disease. Positive Chlamydia pneumoniae (C. pneumoniae) serology is associated with increased levels of inflammatory cytokines and tumor necrosis factor-α (TNF-α), which stimulates endothelial cell activation, procoagulant activity and angiogenesis in patients with coronary heart disease. As a final example, interleukin-6 (IL-6) has been proposed to mediate cardiovascular disorders.
The motor activity of the transverse, descending, and sigmoid colon was recorded for 24 hours in 14 healthy volunteers with a colonoscope positioned catheter. During the study the patients ate two 1000 kcal mixed meals and one continental breakfast. Colonic motor activity was low before meals and minimal during sleep; the motility index increased significantly after meals and at morning awakening. Most of the motor activity was represented by low amplitude contractions present singly or in bursts, which showed no recognisable pattern. All but two subjects also showed isolated high amplitude (up to 200 mmHg) contractions that propagated peristaltically over long distances at approximately 1 cm/sec. Most of these contractions occurred after morning awakening, and some in the late postprandial period, with a mean of 4.4/subject/24 h. The peristaltic contractions were often felt as an urge to defecate or preceded defecation, and could represent the manometric equivalent of the mass movements.
A manometric method was developed to study the motor activity in the unprepared human colon, and the results in eight healthy subjects were compared with those obtained in the same subjects after bowel cleansing with a non-absorbable solution containing polyethylene glycol 4000 (PEG). A tube assembly (4.5 m long, 12 lumen) was introduced through the nose and passed through the gastrointestinal tract. Two manometric recordings were performed one month apart, one without any preparation and the other after bowel cleansing with PEG. There was no obvious qualitative difference between the recordings performed in the uncleansed and PEG cleansed colon. Moreover, in the unprepared colon motility indices were close to those measured in the cleansed colon. The number of high amplitude propagated contractions (mean (SEM)) was, however, higher in the cleansed colon (8.6 (2.8) v 5.4 (1.8)/subject/9 h in the unprepared colon; p < 0.04). It is concluded that in healthy subjects taking a regular diet, motor activity is not different between the uncleansed and cleansed colon with PEG, except for the high amplitude propagated contractions, which occur more frequently in the cleansed colon.
Background: Olestra is a nonabsorbable, energy-free fat substitute. Because it is not absorbed, it may cause digestive symptoms when consumed in large amounts. Objective: To compare the frequency and impact of gastrointestinal symptoms in adults and children who freely consume snacks containing olestra or regular snacks in the home. Design: 6-week, double-blind, randomized, parallel, placebo-controlled trial. Setting: General community. Participants: 3181 volunteers 2 to 89 years of age. Intervention: Households received identical packages labeled as containing olestra corn or potato chips. These packages contained either olestra or regular chips (control). Measurement: Gastrointestinal symptoms and their impact on daily activities were reported in a daily record. Results: At least one gastrointestinal symptom was reported by 619 of 1620 (38.2%) persons in the olestra group and 576 of 1561 (36.9%) controls (difference, 1.3 percentage points [95% CI, -3.6 to 6.2 percentage points]; P = 0.60). In general, the groups did not differ significantly in the proportion of participants who reported individual gastrointestinal symptoms; however, more controls reported nausea (8.4% compared with 5.7%; difference, -2.7 percentage points [Cl, -4.9 to -0.4 percentage points]; P = 0.02). The only difference between groups for the mean numbers of days on which symptoms were reported was that participants in the olestra group had 1 more symptom-day of more frequent bowel movements than did controls (3.7 symptom-days compared with 2.8 symptom days; difference, 0.9 symptom-days [Cl, 0.1 to 1.8 symptom-days]; P = 0.04). The groups did not differ in the impact of symptoms on daily activities. Conclusions: Clinically meaningful or bothersome gastrointestinal effects are not associated with unregulated consumption of olestra corn and potato chips in the home.
Context.— Olestra, a nonabsorbable, energy-free fat substitute used in snack foods,
has been anecdotally reported to cause gastrointestinal (GI) adverse events,
although such effects were not expected based on results from randomized trials,
in which it was consumed in typical snack patterns.Objective.— To determine whether ad libitum consumption of potato chips made with
the fat substitute olestra results in a different level of GI symptoms than
regular chips made with triglyceride (TG).Design.— Randomized, double-blind, parallel, placebo-controlled trial.Setting.— A suburban Chicago, Ill, multiplex cinema.Subjects.— A total of 1123 volunteers aged 13 to 88 years.Intervention.— Subjects were given a beverage and an unlabeled, white 369-g (13-oz)
bag of potato chips made with olestra or TG during a free movie screening.Main Outcome Measures.— Total and specific GI symptoms reported during a telephone interview
conducted from 40 hours to 10 days after ingestion; level of potato chip consumption;
and satiety level.Results.— Of 563 evaluable subjects in the olestra chip group, 89 (15.8%) reported
1 or more GI symptoms, while 93 (17.6%) of the 529 evaluable subjects in the
regular TG chip group did so (difference in symptom frequency between olestra
and TG, −1.8; 95% confidence interval, −6.2 to 2.7; P=.47). For specific GI symptoms (eg, gas, diarrhea, abdominal cramping),
there were no significant differences between olestra and TG chips. Fewer
olestra chips were consumed than TG chips (60 vs 77 g [2.1 vs 2.7 oz]; P<.001), with olestra chips receiving lower taste scores
(5.6 vs 6.4 on a 9-point scale; P <.001). Consumption
levels did not correlate with the rate of symptom reporting in either the
olestra or TG group. There was no difference in satiety scores between olestra
and TG chips (5.7 vs 5.9 on a 9-point scale; P =.07).Conclusions.— This study demonstrates that ad libitum consumption of olestra potato
chips during 1 sitting is not associated with increased incidence or severity
of GI symptoms, nor does the amount consumed predict who will report GI effects
after short-term consumption of either olestra or TG potato chips.
Abdominal symptoms due to motility disturbances of the lower gut consist mainly of discrete pain episodes or a long-lasting feeling of fullness and distension. Long-term recording has shown that these symptoms are partly related to propagated contraction waves of the colon which induce mass movement of colonic contents. Patients probably experience that normal contractile activity is unpleasant or painful and apparently have a decreased threshold of perception. Also, peculiar contraction patterns of the small intestine ('clustered contractions') have been related to pain episodes. Fullness and distension are characteristic for slow transit constipation, but also occur in disordered defecation. Future studies on treatment will have to concentrate on pathophysiologically defined subgroups.
(C) Lippincott-Raven Publishers.
We wished to determine if visceral perception in the rectum and stomach is altered in patients with irritable bowel syndrome and to evaluate the effects on visceral sensation of 5-HT3 receptor blockade. Twelve community patients with diarrhea-predominant irritable bowel syndrome and 10 healthy controls were studied in a double-blind, randomized, placebo-controlled study. Using two barostats, the stomach and rectum were distended, with pressure increments of 4 mm Hg, from 10 to 26 mm Hg; visceral perception was measured on an ordinal scale of 0–10. Personality traits were measured using standard psychological methods, and somatic pain was evaluated by immersion of the nondominant hand in cold water. The effect of 5-HT3 antagonism was tested with a single intravenous dose of ondansetron at 0.15 mg/kg. Gastric perception was higher in irritable bowel syndrome, but rectal distension was perceived similarly in irritable bowel syndrome and controls. Pain tolerance to cold water was also similar in irritable bowel syndrome and controls. Ondansetron induced rectal relaxation and increased rectal compliance but did not significantly alter gastric compliance or visceral perception. Psychological test scores were similar in patients and controls. We conclude that in this group of psychologically normal patients with irritable bowel syndrome, who were not chronic health-care seekers, visceral perception was normal. Ondansetron did not alter gut perception in health or in irritable bowel syndrome.
The increase in stool weight after feeding 20 g (dry weight) of bran daily was measured when this was of large particle size and after milling to small particle size. Twenty-eight investigations were carried out in 21 normal subjects. With coarse bran, stool weight was significantly greater than with the fine bran (mean 219.4 g/d coarse bran, 199-0 g/d fine bran: difference 20.4 g SE +/-6.4, P less than 00.1). The coarse bran also had a greater water-holding capacity (7.3 g water/g coarse bran, 3.9 water/g fine bran). Coarse bran was 2 1/2 times the volume of fine gran for a given weight and more fine bran will, therefore, be taken when bran is prescribed by the spoonful.
Crude fiber analysis does not accurately reflect the amount of dietary fiber in food materials, nor does it give a constant fraction of dietary fiber when used to compare sources in the diet. More accurate methods of estimating dietary fiber are compared. The neutral detergent method of Van Soest, modified for use with foods, was especially useful in measuring the insoluble fraction of dietary fiber. It not only provided a simple, quick method of analysis but also was useful in isolating dietary fiber for further experimentation. Water-holding capacity studies, trace mineral binding studies, and bile acid binding studies were run on the insoluble dietary fiber without interference from digestible food constituents.
Low fecal weight and slow bowel transit time are thought to be associated with bowel cancer risk, but few published data defining bowel habits in different communities exist. Therefore, data on stool weight were collected from 20 populations in 12 countries to define this risk more accurately, and the relationship between stool weight and dietary intake of nonstarch polysaccharides (NSP) (dietary fiber) was quantified. In 220 healthy U.K. adults undertaking careful fecal collections, median daily stool weight was 106 g/day (men, 104 g/day; women, 99 g/day; P = 0.02) and whole-gut transit time was 60 hours (men, 55 hours; women, 72 hours; P = 0.05); 17% of women, but only 1% of men, passed < 50 g stool/day. Data from other populations of the world show average stool weight to vary from 72 to 470 g/day and to be inversely related to colon cancer risk (r = -0.78). Meta-analysis of 11 studies in which daily fecal weight was measured accurately in 26 groups of people (n = 206) on controlled diets of known NSP content shows a significant correlation between fiber intake and mean daily stool weight (r = 0.84). Stool weight in many Westernized populations is low (80-120 g/day), and this is associated with increased colon cancer risk. Fecal output is increased by dietary NSP. Diets characterized by high NSP intake (approximately 18 g/day) are associated with stool weights of 150 g/day and should reduce the risk of bowel cancer.
Gastrointestinal transit time, frequency of defecation, stool weight, and stool consistency were studied in 12 subjects who were each given fiber supplements containing wheat bran, psyllium gum, a combination of wheat bran and psyllium gum, or a low-fiber control for 2 weeks. Gastrointestinal transit time was measured using four different markers: plastic pellets, chromium mordanted bran, cobalt-ethylenediamine-tetraacetic acid, and terbium oxide. The wet weight and dry weight of stools were measured, and a questionnaire accessed subjects' perceptions of the consistency of their stools. Fiber supplementation decreased transit time and increased the daily number of defecations and the wet weight and dry weight of stools. Bran had a greater effect on transit time than psyllium. Psyllium had a greater effect on the amount of water found in the stools and the total stool weight. On the days that stools were passed, 50% of the daily stool ratings were scored as "hard" when subjects received the control supplement. Less than 10% of the ratings were scored as "hard" when subjects received the high-fiber supplements. The type of marker used did not significantly affect the transit time measured.
Feeding animals large quantities of dry hydrophilic fiber sources, such as psyllium husk or guar gum, may lead to intestinal obstruction or to other mechanical effects unrelated to the normal function of these materials in human diets. Such fiber sources should be hydrated prior to feeding, rather than being incorporated into dry diets as is. The water-holding capacity of psyllium hydrophilic mucilloid, for example, is greater than or equal to 40 g/g, compared to 2-3 g/g of wheat bran. Consumption of the psyllium product dry would be much more likely to produce intestinal dehydration than would consumption of dry bran. Because of possible untoward effects of high levels of these materials, it may also be more appropriate to feed such fiber sources in quantities approximating that of their potential human dietary consumption, rather than very high quantities that would be unlikely to be attained in human diets.
The motor activity of colonic segments proximal to the rectosigmoid junction are poorly understood. We investigated colonic peristalsis (high-amplitude propagated contractions; HAPCs) in 20 healthy volunteers by means of a colonoscopically positioned manometric probe and low-compliance infusion system. In all, 110 HAPCs were recorded from the ascending, transverse, descending, and sigmoid colon, and their features and daily distribution were analyzed and characterized. Mean frequency was 6.1 +/- 0.9 (SE) per subject per 24 h, mean amplitude was 110.37 +/- 6.3 mmHg, mean duration was 14.15 +/- 0.8 s, and mean propagation velocity was 1.11 +/- 0.1 cm/s. There were no significant differences among colonic segments. Diurnal changes of HAPCs were also noted, with a maximum frequency after meals and after awakening in the morning, and a minimum recorded in the late afternoon and during the night. These HAPCs may represent the manometric equivalent of mass movements.
Data has been produced to support a hypothesis that high consumption of natural starchy carbohydrates, taken with their full complement of fiber, is protective against hyperlipidemia and IHD. Experiments in animals and man may be interpreted to support a suggestion that dietary fiber decreases the reabsorption of bile salts, increases fecal excretion, and reduces hyperlipidemia.
The effect of particle size of dietary wheat bran on human colonic function was studied in young adult men. Controlled, low-fiber diets supplemented with 32 g of either coarse or finely ground bran were served daily in a metabolic unit. Measurements of the mean transit time were made using polyethylene glycol and barium impregnated radioopaque pellets. In subjects receiving equal levels of both bran diets, coarse bran produced significantly (P = 0.95) shorter mean transit time than did finely ground bran. Values of mean transit time for coarse bran were 42.3 hr (polyethylene glycol) and 37.4 hr (pellets) while 57.9 hr (polyethylene glycol) and 56.5 hr (pellets) were found for fine bran. Daily fecal wet and dry weights from the coarse bran diet were found to be significantly greater by 14% (P = 0.99) and 7% (P = 0.95) than the weights found during the ingestion of finely ground bran. The moisture content of feces from subjects receiving the coarse bran diet was 75.2%, significantly higher (P = 0.99) than the value of 72.3% found with fine bran. No significant differences in the number of defecations per day were noted. Mean digestibilities for hemicellulose was 50% for coarse bran and 54% for fine bran. Cellulose digestibility was 6% in the coarse bran diet and 23% in the fine bran. While significant differences (P = 0.95) in digestibilities between the two brans were not shown, mean digestibilities were greater for fine bran components. Results from this study indicate that finely ground wheat bran is less effective than coarse bran in holding water in the feces and in promoting rapid transit of digesta through the gut. These findings suggest that coarse bran and food products fortified with coarsely ground bran should be the choice of patients with diverticular disease and of people desiring a high fiber diet to promote colonic health. Am. J. Clin. Nutr. 33: 1734-1744, 1980.
Intestinal reflexes induced by distention in dogs are facilitated by either simultaneous or previous distentions. The aim of this study was to determine whether these phenomena also modulate the responses to intestinal distention, particularly perception, in humans.
Perception and intestinal relaxation were measured in 11 healthy subjects in response to increasing jejunal balloon distentions tested (by stimulus-response trials) alone, as control, and with conditioning distentions applied either simultaneously, immediately (10 seconds) before at the same site, or immediately before and 5 cm distant. In 8 additional subjects, the effect of prolonged (90-minute) conditioning distention was tested.
Conditioning had more pronounced effects on perception than on intestinal reflexes. Perception of intestinal distention increased (by 84 +/- 47%; P < 0.05) when a simultaneous distention was applied nearby. By contrast, perception decreased (by 38 +/- 12%; P < 0.05) when a previous distention was applied at the same but not at an adjacent site. Prolonged intestinal distention elicited remarkably stable perception during a 90-minute period. The effects of conditioning were unrelated to intestinal compliance because it remained unchanged.
In humans, temporospatial interactions of gut stimuli activate modulatory phenomena that determine the perception intensity of the stimuli.
We wished to determine if visceral perception in the rectum and stomach is altered in patients with irritable bowel syndrome and to evaluate the effects on visceral sensation of 5-HT3 receptor blockade. Twelve community patients with diarrhea-predominant irritable bowel syndrome and 10 healthy controls were studied in a double-blind, randomized, placebo-controlled study. Using two barostats, the stomach and rectum were distended, with pressure increments of 4 mm Hg, from 10 to 26 mm Hg; visceral perception was measured on an ordinal scale of 0-10. Personality traits were measured using standard psychological methods, and somatic pain was evaluated by immersion of the nondominant hand in cold water. The effect of 5-HT3 antagonism was tested with a single intravenous dose of ondansetron at 0.15 mg/kg. Gastric perception was higher in irritable bowel syndrome, but rectal distension was perceived similarly in irritable bowel syndrome and controls. Pain tolerance to cold water was also similar in irritable bowel syndrome and controls. Ondansetron induced rectal relaxation and increased rectal compliance but did not significantly alter gastric compliance or visceral perception. Psychological test scores were similar in patients and controls. We conclude that in this group of psychologically normal patients with irritable bowel syndrome, who were not chronic health-care seekers, visceral perception was normal. Ondansetron did not alter gut perception in health or in irritable bowel syndrome.
Up to 60% of patients with IBS have lowered perception thresholds in the rectum to balloon distension. The current study sought to test the hypothesis that IBS patients with normal perception thresholds in the rectum show hypersensitivity of afferent pathways in the sigmoid colon. Eleven healthy normal subjects and eight IBS patients with normal rectal perception thresholds underwent a balloon distension protocol in the sigmoid and rectum. Discomfort thresholds, receptive relaxation, compliance, and referral patterns were measured. Although IBS patients had significantly lower discomfort thresholds in the sigmoid when measured as volume, pressure, and wall tension, thresholds were similar to normals. Receptive relaxation and dynamic compliance were significantly decreased in IBS patients in the sigmoid. Referral patterns were similar during sigmoid distention in IBS patients in comparison to normals. Despite normal perception thresholds in rectum and sigmoid, IBS patients show evidence for alterations in rectosigmoid afferent mechanisms. In the sigmoid, this is seen in the form of reduced reflex relaxation and compliance and in the rectum in the form of altered viscerosomatic referral.
Potential chronic (14-d average) and acute (single-day) estimated daily intakes (EDI) were computed for olestra, a fat replacement intended for use in preparing savory snacks. The EDI were computed from eating occasions reported during a 14-d Menu Census survey among 4741 consumers; values were increased by 10% for conservatism. The eating occasions included all meals and in-between meal occasions eaten at home or away. Data from only those individuals who ate savory snacks at least once during the 14 d were used; this included 3820 individuals (81% of the sample) and represented a total of 16,067 eating days (24% frequency). The estimated mean chronic intake ranged from 1.8 to 4.7 g/d, depending on age and gender; at the 90th percentile, the range was 4.1-11.0 g/d. For all ages and both genders, the estimated mean intake was 3.1 g/d. Estimated acute intakes at the mean and 90th percentile ranged from 5.5 to 16.5 g/d and from 10.2 to 24.0 g/d, respectively, depending on age and gender. For all ages and both genders, the estimated mean intake was 10.2 g/d. The lack of parity in the chronic and acute intake estimates indicates that savory snacks are not eaten on a daily basis by the majority of snack eaters. The survey data were analyzed to understand the potential temporal eating patterns of olestra from savory snacks. When snacks were consumed, on average, 69% of the eating occasions were with main meals and 31% were between meals. Savory snacks did not contribute a major fraction of total food to the diet; only 7 and 18% of main meals contained a savory snack food at the 50th and 90th percentile, respectively. For the 50th-percentile consumer (all ages, both genders), savory snacks were eaten four times during the 14-d survey period, and the eating occasions occurred on 3 d. Comparable results for 90th-percentile consumers were 10 eating occasions and 8 eating days.
Olestra is a zero-calorie fat substitute that is neither digested nor absorbed. A randomized, double-blind, placebo-controlled, within-subject, crossover rechallenge study was conducted to compare the occurrence of gastrointestinal symptoms after ingestion of chips made with Olean brand of olestra or conventional triglycerides in subjects who had previously experienced gastrointestinal symptoms they attributed to consuming Olean. A total of 57 male or female subjects received 2 oz of Olean potato chips or triglyceride potato chips at each of four weekly site visits. The occurrence of gastrointestinal effects after product consumption was noted in follow-up telephone interviews 3 to 5 days after each visit. There was no significant difference in the frequency of any gastrointestinal symptoms (abdominal cramping, diarrhea, loose stools) following consumption of Olean chips or triglyceride chips, and the severity of diarrhea, loose stools, and abdominal cramping was similar. We conclude that consumption of a 2-oz serving of Olean chips is no more likely to result in reports of gastrointestinal symptoms than consumption of triglyceride snacks as a part of the usual diet, even in individuals who have claimed intolerance to Olean. The data suggest that subjects who previously experienced symptoms that they attributed to consuming products made with Olean may have mistakenly attributed their symptoms to these products.
Olestra, a nonabsorbable, energy-free fat substitute used in snack foods, has been anecdotally reported to cause gastrointestinal (GI) adverse events, although such effects were not expected based on results from randomized trials, in which it was consumed in typical snack patterns.
To determine whether ad libitum consumption of potato chips made with the fat substitute olestra results in a different level of GI symptoms than regular chips made with triglyceride (TG).
Randomized, double-blind, parallel, placebo-controlled trial.
A suburban Chicago, III, multiplex cinema.
A total of 1123 volunteers aged 13 to 88 years.
Subjects were given a beverage and an unlabeled, white 369-g (13-oz) bag of potato chips made with olestra or TG during a free movie screening.
Total and specific GI symptoms reported during a telephone interview conducted from 40 hours to 10 days after ingestion; level of potato chip consumption; and satiety level.
Of 563 evaluable subjects in the olestra chip group, 89 (15.8%) reported 1 or more GI symptoms, while 93 (17.6%) of the 529 evaluable subjects in the regular TG chip group did so (difference in symptom frequency between olestra and TG, -1.8; 95% confidence interval, -6.2 to 2.7; P=.47). For specific GI symptoms (eg, gas, diarrhea, abdominal cramping), there were no significant differences between olestra and TG chips. Fewer olestra chips were consumed than TG chips (60 vs 77 g [2.1 vs 2.7 oz]; P<.001), with olestra chips receiving lower taste scores (5.6 vs 6.4 on a 9-point scale; P<.001). Consumption levels did not correlate with the rate of symptom reporting in either the olestra or TG group. There was no difference in satiety scores between olestra and TG chips (5.7 vs 5.9 on a 9-point scale; P=.07).
This study demonstrates that ad libitum consumption of olestra potato chips during 1 sitting is not associated with increased incidence or severity of GI symptoms, nor does the amount consumed predict who will report GI effects after short-term consumption of either olestra or TG potato chips.
We recently showed that activation of the hypothalamus-pituitary-adrenal axis may mitigate the progress of acute pancreatitis. To clarify the mechanism, the role of endogenous glucocorticoids in pancreatic acinar cell death was examined.
The occurrence of apoptosis was studied in adrenalectomized or sham-operated rats with or without cerulein-induced pancreatitis. The effects of RU38486, a glucocorticoid-receptor antagonist, on the survival of cultured acinar cells (AR42J) were also examined.
Adrenalectomy caused increases in terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) of acinar nuclei depending on the time after adrenalectomy but not of other cell types in the pancreas and in other digestive organs. Electron microscopy showed the characteristic features of apoptosis in the TUNEL-labeled acinar cells. In cerulein pancreatitis of adrenalectomized rats, the TUNEL-labeled acinar nuclei increased remarkably depending on the time after cerulein infusion. Replacement of glucocorticoids blocked the occurrence of apoptosis in these experiments. RU38486 induced dose dependently the apoptosis of AR42J cells.
These results provide evidence that endogenous glucocorticoids are an important factor for acinar cell survival. Endogenous glucocorticoids may protect acinar cells by decreasing their sensitivity to the induction of cell death during acute pancreatitis.
The aim of this study was to determine how bulk fibers and calcium docusate affect regional dehydration and digesta viscosity throughout the large intestine. Fifty-two pigs were fed a chow diet supplemented with a bulk laxative, placebo, or calcium docusate for three days, after which the pigs were sacrificed and the contents of the large bowel were analyzed. Digesta occurred as a continuum from liquid (cecum, 91.2% water content) to solid (rectum, 70.5% water content). The observed 20.7% difference in water content resulted in a 240-fold increase in viscosity. Half of this water is reabsorbed in the first 18% of the large bowel length where viscosity remains relatively low. Compared to placebo, calcium docusate and calcium polycarbophil had no significant effect on digesta water content or viscosity, polycarbophil exhibited significantly (P < 0.05) lower digesta viscosity in three bowel segments, and psyllium exhibited significantly (P < 0.01) lower viscosity in six bowel segments and higher water content in nine bowel segments. In conclusion, the majority of digesta dehydration occurs early in the proximal large bowel, while the greatest increases in viscosity occur in the distal bowel. Relatively small decreases in digesta water content result in large increases in digesta viscosity. Psyllium, and to a lesser extent polycarbophil, are able to resist dehydration, resulting in a softer digesta.
Stool softening is a physician's first step in the management of chronic constipation.
To compare stool softening (stool water content) and laxative efficacy of psyllium hydrophilic mucilloid vs. docusate sodium.
The multi-site, randomized, double-blind, parallel-design study of 170 subjects with chronic idiopathic constipation involved a 2-week baseline (placebo) phase followed by 2 weeks of treatment. The treatment phase compared psyllium (5.1 g b.d.) plus docusate placebo to docusate sodium (100 mg b.d.) plus psyllium placebo. Stools were collected and assessed.
Compared to baseline, psyllium increased stool water content vs. docusate (psyllium 2.33% vs. docusate 0.01%, P = 0.007). Psyllium also increased stool water weight (psyllium 84.0 g/BM; docusate 71.4 g/BM; P = 0.04), total stool output (psyllium 359.9 g/week: docusate 271.9 g/week; P = 0.005), and O'Brien rank-type score combining objective measures of constipation (psyllium 475.1; docusate 403.9; P = 0.002). Bowel movement (BM) frequency was significantly greater for psyllium (3.5 BM/week) vs. docusate (2.9 BM/week) in treatment week 2 (P = 0.02), with no significant difference (P > 0.05) between treatment groups in treatment week 1 (3.3 vs. 3.1 BM/week).
Psyllium is superior to docusate sodium for softening stools by increasing stool water content, and has greater overall laxative efficacy in subjects with chronic idiopathic constipation.
Olestra is a nonabsorbable, energy-free fat substitute. Because it is not absorbed, it may cause digestive symptoms when consumed in large amounts.
To compare the frequency and impact of gastrointestinal symptoms in adults and children who freely consume snacks containing olestra or regular snacks in the home.
6-week, double-blind, randomized, parallel, placebo-controlled trial.
General community.
3181 volunteers 2 to 89 years of age.
Households received identical packages labeled as containing olestra corn or potato chips. These packages contained either olestra or regular chips (control).
Gastrointestinal symptoms and their impact on daily activities were reported in a daily record.
At least one gastrointestinal symptom was reported by 619 of 1620 (38.2%) persons in the olestra group and 576 of 1561 (36.9%) controls (difference, 1.3 percentage points [95% CI, -3.6 to 6.2 percentage points]; P = 0.60). In general, the groups did not differ significantly in the proportion of participants who reported individual gastrointestinal symptoms; however, more controls reported nausea (8.4% compared with 5.7%; difference, -2.7 percentage points [CI, -4.9 to -0.4 percentage points]; P = 0.02). The only difference between groups for the mean numbers of days on which symptoms were reported was that participants in the olestra group had 1 more symptom-day of more frequent bowel movements than did controls (3.7 symptom-days compared with 2.8 symptom days; difference, 0.9 symptom-days [CI, 0.1 to 1.8 symptom-days]; P = 0.04). The groups did not differ in the impact of symptoms on daily activities.
Clinically meaningful or bothersome gastrointestinal effects are not associated with unregulated consumption of olestra corn and potato chips in the home.
The mechanisms by which dietary fiber exerts its laxative action are not fully understood. Finely grinding wheat bran reduces its effect. Inert plastic particles are equipotent to bran if they consist of flakes or sliced tubing. It is not known whether altering the size or shape of inert particles alters their effect on intestinal function. In a randomized crossover study, 18 volunteers swallowed 24 g/day of plastic as branlike flakes or as small granules for 10-12 days with a two-week washout period between interventions. Whole-gut transit time (WGTT), orocecal transit time (OCTT), defecation frequency, stool form, stool water content, stool pH, and dietary intake were assessed. The plastic flakes caused a 24% (P < 0.001) reduction in WGTT and a 19% (P = 0.002) fall in OCTT. Resultant and appropriate changes in stool form, interdefecatory intervals (IDI), and stool weight were seen. The small granules did not cause any significant change in WGTT or OCTT, although IDI did decrease and stool output and stool form score increased. The stimulant effect of solid particles in the intestinal lumen upon transit time is influenced by the morphology of the particles.
The goal of this study was to compare the stool-softening effects of olestra and wheat bran and to determine if changes in patterns of propagating colonic motility were associated with the observed stool softening. Mini-pigs were fed chow (control) or chow supplemented with olestra (80 g/day) or wheat bran (80 g/day) for four days. Proximal colonic motility was monitored continuously, stool viscosity and fecal output measured daily, and cecal-to-anal transit time determined. Compared to controls, olestra and wheat bran significantly softened stool but had no effect on fecal wet weight or colonic transit time. Neither olestra nor wheat bran changed the number of propagating contractions per day, amplitude, motility index, propagation velocity, or the relative distribution of fast and slow propagating contractions. Our data suggest that the stool-softening effects of olestra and wheat bran are not due to direct stimulation of propagating contractions in the colon of the mini-pig.
The aim of this study was to determine the effects of olestra and sorbitol consumption on three accepted objective measures of diarrhea (stool output >250 g/day, liquid/watery stools, bowel movement frequency >3/day), and how stool composition influences reports of common gastrointestinal symptoms. A double-blind, placebo-controlled study compared the effects of sorbitol (40 g/day in candy), a poorly absorbed sugar-alcohol with known osmotic effects, with those of olestra (20 or 40 g/day in potato chips), a nonabsorbed fat, on objective measures of stool composition and GI symptoms. Sixty-six subjects resided on a metabolic ward for 12 days: 2 days lead-in, 4 days baseline, 6 days treatment. Sorbitol 40 g/day resulted in loose/liquid stools within 1-3 h of consumption. In contrast, olestra resulted in a dose-responsive stool softening effect after 2-4 days of consumption. Subjects reported "diarrhea" when mean stool apparent viscosity (peak force (PF), g) decreased from a perceived "normal" (mean +/- SE, 1355 +/- 224 g PF; firm stool) to loose (260 +/- 68 g PF) stool. Mean apparent viscosity of stool during treatment: placebo, 1363 +/- 280 g (firm); olestra 20 g/day 743 +/- 65 g (soft); olestra 40 g/day, 563 +/- 105 g (soft); and sorbitol 40 g/day, 249 +/- 53 g (loose). Of the 1098 stool samples collected, 38% (419/1098) were rated by subjects as "diarrhea," yet only 2% of treatment days (all in the sorbitol treatment group) met commonly accepted criteria for a clinical diarrhea. Sorbitol, but not olestra, increased the severity of abdominal cramping, urgency and nausea compared to placebo. Olestra consumption, at levels far in excess of normal snacking conditions, resulted in a gradual stool softening effect after several days of consumption, did not meet any of the three objective measures of diarrhea, and did not increase GI symptoms. Sorbitol consumption, at only 80% of the dose requiring a "laxative effect" information label, resulted in rapid onset loose/liquid stools and a significant increase in abdominal cramping, urgency and nausea. Overall, subjects categorized stool as "diarrhea" when stool decreased from their perceived "normal," but the vast majority of these reports were not associated with clinically significant diarrhea.
Fecal weight, colon cancer risk, and dietary intake of nonstarch polysaccha-rides (dietary fiber)
- Cummings Jh Bingham
- Sa
- Heaton
- Kw
Cummings JH, Bingham SA, Heaton KW, et al. Fecal weight, colon cancer risk, and dietary intake of nonstarch polysaccha-rides (dietary fiber). Am J Gastroenterol 1992;103:1783–9.
Department of Health, and Human Services, Food, and Drug Administration, 21 CFR Part 172
- Federal Register
- Iii Part