A comparative study of the effects on colon function caused by feeding ispaghula husk and polydextrose

Re-evaluation of polydextrose (E 1200) as a food additive

This opinion deals with the re-evaluation of polydextrose (E 1200) when used as a food additive. The Panel followed the conceptual framework for the risk assessment of certain additives and considered that: adequate exposure estimates were available; the margin of safety (MOS)/margin of exposure (MOE) for arsenic was between 0.5-14 and 8.5 for lead; the exhaustions of the tolerable weekly intake (TWI) for cadmium would be 165%, 10% for mercury, whereas the exhaustion of the tolerable daily intake (TDI) for nickel would be 9%; the absorption is limited and part of polydextrose is fermented in the large intestine into short-chain fatty acids (SCFA); adequate toxicity data were available; there is no concern with respect to genotoxicity; no adverse effects were reported in subchronic studies in rats, dogs or monkeys nor in chronic or carcinogenicity studies in mice and rats at the highest doses tested of up 12,500 mg/kg body weight (bw) per day and 15,000 mg/kg bw per day, respectively; the nephrocalcinosis in dogs given high doses of polydextrose was considered to be a treatment-related but a secondary effect related to diarrhoea, and hence not relevant for the risk assessment; no adverse effects were reported in reproductive or developmental toxicity studies in rats administered up to 10,000 mg polydextrose/kg bw per day, or in a developmental toxicity study in rabbits up to 1,818 mg/kg bw per day (the highest dose tested). Therefore, the Panel concluded that there is no need for numerical acceptable daily intake (ADI) for polydextrose (E 1200), and that there is no safety concern for the reported uses and use levels of polydextrose as a food additive. The Panel recommended that European Commission considers to lower the maximum limit for lead and to introduce limits for arsenic, cadmium and mercury in the EU specifications for polydextrose (E 1200), and to verify that polydextrose-N as a food additive (E 1200) is no longer marketed in the EU.

Laxative effects of wheat bran and psyllium: Resolving enduring misconceptions about fiber in treatment guidelines for chronic idiopathic constipation

BACKGROUND

Treatment guidelines for chronic idiopathic constipation (CIC) recommend an "increase in fiber intake" as a first-line therapy, but most epidemiologic studies fail to support an association between a high-fiber diet and a reduced risk of constipation. Furthermore, randomized controlled clinical studies show that most isolated fibers (e.g., supplements) are not different from placebo for a laxative effect, and several may be constipating.

OBJECTIVES

The objective of this review was to compare the effects of two isolated fibers, coarse wheat bran and psyllium, on stool output and stool water content in patients with CIC. This review will also address misconceptions about fiber that are perpetuated by treatment guidelines.

DATA SOURCES

A comprehensive literature review was conducted with the use of the Scopus, SciFinder, and PubMed scientific databases, limited to the previous 50 years (1968-2018; latest date included, December 31, 2018).

CONCLUSIONS

In patients with CIC, nonfermented gel-forming psyllium was 3.4 times more effective than insoluble wheat bran for increasing stool output. Both psyllium and coarse wheat bran increased stool water content, a stool-softening effect, but finely ground wheat bran decreased stool water content, a stool-hardening effect.

IMPLICATIONS FOR PRACTICE

It is a misconception that dietary fiber and all isolated fibers provide a laxative effect in patients with CIC. Our analysis suggests that treatment guidelines for CIC should make specific evidence-based recommendations as it pertains to fiber. To do otherwise takes the risk of perpetuating myth and misunderstanding and depriving patients of an effective therapy for CIC. A generic recommendation to "increase fiber intake" is akin to a recommendation to "increase pill intake" without regard to therapeutic or adverse effects.

Efficacy of Polydextrose Supplementation on Colonic Transit Time, Bowel Movements, and Gastrointestinal Symptoms in Adults: A Double-Blind, Randomized, Placebo-Controlled Trial

The addition of fiber is one of the most important dietary means to relieve constipation through lifestyle modification. Polydextrose (PDX) has been reported in several studies to increase fecal bulk, soften stools, and increase the number of defecations. However, there are few studies on the effect of PDX on colonic transit time (CTT). Therefore, the aim of this study was to demonstrate the effect of PDX on CTT and other aspects of gastrointestinal function during two weeks (Day 1 to Day 14), preceded by a 2-week run-in period (Day -14 to Day -1). A total of 192 adults who were diagnosed with functional constipation per Rome III criteria were recruited for the study. Participants were randomized equally into 4 groups (12 g, 8 g, or 4 g of PDX or placebo per day). The primary endpoint was CTT, assessed using radio-opaque markers and abdominal X-rays on Day 0, the baseline; and Day 15, the end of the intervention. Secondary outcomes that were measured using inventories were the patient assessment of constipation symptoms and quality of life, bowel function index, relief of constipation, bowel movement frequency (BMF), stool consistency, degree of straining, and proportion of bowel movements. Ancillary parameters and harms were also evaluated. The recruited population was not sufficiently constipated (e.g., baseline values for CTT and BMF of 42 h and 8.7 BMF/week, respectively). Despite this limitation, our results demonstrated an increased number of bowel movements when supplemented with PDX at a dosage of 12 g per day for 2 weeks. This dosage also consistently improved the secondary outcomes that were measured using inventories at Day 15, compared with the baseline. No serious or significant adverse events were reported during the study.

Short-Term Daily Intake of Polydextrose Fiber Does Not Shorten Intestinal Transit Time in Constipated Adults: A Randomized Controlled Trial

Chronic constipation (CC) remains a common gastrointestinal (GI) disorder that conveys a substantial healthcare burden. Expert guidelines recommend increasing fiber intake, yet the clinical evidence to support this needs strengthening for specific fibers. The aim was to evaluate changes in intestinal transit time and GI symptoms in CC patients who consumed polydextrose. In a randomized, double-blind, placebo-controlled trial, 128 adults with CC received 8 g or 12 g polydextrose, or placebo, daily for 4 weeks. Transit time, as primary outcome, was assessed by radiopaque marker distribution after 2-weeks intervention. Bowel habits, GI symptoms and quality of life (QOL) were assessed by questionnaire, including the Patient-Assessment of Constipation (PAC) Symptoms (SYM), and PAC-QOL. Following 2-weeks intervention, no reduction was seen in transit time in any group and following 2- or 4-weeks intervention, no improvements were seen in stool frequency or consistency in any group. After 2-weeks intervention with 8 g/day polydextrose an improvement was seen in the PAC-SYM rectal score (p = 0.041). After 4-weeks intervention both rectal (p = 0.049) and stool (p = 0.029) scores improved while improvement in the QOL satisfaction score did not reach significance (p = 0.071). Overall, the results suggest that 2-weeks consumption of 8 or 12 g/day polydextrose does not significantly improve physiological measures of gut function in CC adults. Longer term consumption may improve clinical measures, but further studies will be required to substantiate this.

Digestion-resistant maltodextrin effects on colonic transit time and stool weight: a randomized controlled clinical study

PURPOSE

Increased awareness of the importance of dietary fibre has led to increased interest in "functional" fibre components like digestion-resistant maltodextrin (RMD). This randomized, placebo-controlled, double-blind study assessed the effects of RMD in the colonic transit time (CTT) and defecation characteristics (frequency, stool volume and consistency).

METHODS

Sixty-six healthy adult volunteers (32 men) who did not have a daily defecation habit had a 7-day run-in period before the 21-day intervention period with RMD or placebo. CTT and segmental CTT (SCTT) were assessed by a single abdominal X-ray film taken at the end of both periods after radiopaque marker ingestion. Defecation characteristics and intestinal functions were also assessed, which were self-reported by patients. Intragroup comparisons were evaluated by Student's paired t test, Bonferroni test and Chi-square test, while time comparisons by analysis of variance (ANOVA) and time-by-treatment interaction by repeated-measures ANOVA.

RESULTS

Fifty-seven subjects were assessed for CTT (placebo, n = 28; RMD, n = 29). In the RMD group, the total CTT, left SCTT and rectosigmoidal SCTT decreased significantly compared to baseline (p < 0.01 each; -13.3, -4.7, -8.7 h, respectively). Significant differences between groups were observed in total CTT and left SCTT. Significant time-by-treatment interaction was observed in the RMD group for stool volume (p = 0.014), increasing 56 % compared to baseline (p < 0.01), while remained unchanged in the placebo group. Stool consistency was improved only in the RMD group (p < 0.01). No adverse effects related to study products were observed.

CONCLUSIONS

The results show that RMD improved CTT, stool volume, stool consistency and some intestinal functions in a healthy population.

Fermented Fiber Supplements Are No Better Than Placebo for a Laxative Effect

BACKGROUND

Misconceptions about the effects of dietary fiber and 'functional' fiber on stool parameters and constipation persist in the literature.

METHODS

A 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.

RESULTS

The 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., β-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.

Polydextrose and soluble corn fiber increase five-day fecal wet weight in healthy men and women

Dietary fiber has well-established beneficial effects on laxation. Many fibers have been developed with positive sensory properties and 2 such fibers are polydextrose (PDX) and soluble corn fiber (SCF), which can be added to many commercially produced products. We conducted a randomized, double-blind, placebo-controlled, crossover study comparing the laxative effects of PDX and SCF at a dose of 20 g/d with a low fiber control (LFC) eaten daily as a muffin and cereal in 36 healthy men and women. Each treatment period was 10 d with a 2-wk washout period between. Participants collected fecal samples during the last 5 d of each treatment and completed food diaries and gastrointestinal tolerance questionnaires on d 1, 2, and 10 of each treatment period. Five-day fecal wet weight was higher after the PDX and SCF treatments than the LFC treatment (P ≤ 0.0007). The number of stools per day and daily fecal output also were significantly greater during the PDX treatment compared with the LFC treatment. The whole gut transit time did not differ among treatments. The PDX treatment resulted in a softer stool (P = 0.002) than the SCF and LFC treatments. Fecal pH was lowered by the PDX treatment (P = 0.02), whereas SCF tended to lower it compared with the LFC treatment (P = 0.07). When the participants consumed PDX and SCF, they reported significantly more flatulence and borborygmi compared with when they consumed the LFC. Consumption of PDX and SCF at a dose of 20 g/d results in a mild laxative effect with nominal gastrointestinal tolerance issues.

Dietary polydextrose prevents inflammatory bowel disease in trinitrobenzenesulfonic acid model of rat colitis

Inflammatory bowel disease (IBD) is a multifactorial intestinal disorder that involves interactions among the immune system, genetic susceptibility, and environmental factors, especially the bacterial flora. Polydextrose, a polysaccharide constituted by 90% nondigestible and nonabsorbable soluble fibers, has several physiological effects consistent with those of dietary fibers, including proliferation of colon microflora. Because sulfasalazine presents serious side effects through long-term use at high doses, the aim of the present study was to evaluate the preventative effect of polydextrose on trinitrobenzenesulfonic acid-induced intestinal inflammation and its effects on the intestinal anti-inflammatory activity of sulfasalazine. Results indicated that polydextrose and its association with sulfasalazine present an anti-inflammatory effect that reduces myeloperoxidase activity, counteracts glutathione content, and promotes reductions in lesion extension and colonic weight/length ratio.

Dietary fiber type reflects physiological functionality: comparison of grain fiber, inulin, and polydextrose

Dietary fiber is a nutritional concept based not on physiological functions but on defined chemical and physical properties. Recent definitions of dietary fiber differentiate inherent plant cell wall-associated fiber from isolated or synthetic fiber. For the latter to be defined as fiber, beneficial physiological effects should be demonstrated, such as laxative effects, fermentability, attenuation of blood cholesterol levels, or postprandial glucose response. Grain fibers are a major natural source of dietary fiber worldwide, while inulin, a soluble indigestible fructose polymer isolated from chicory, and polydextrose, a synthetic indigestible glucose polymer, have more simple structures. Inulin and polydextrose show many of the same functionalities of grain fiber in the large intestine, in that they are fermentable, bifidogenic, and laxative. The reported effects on postprandial blood glucose and fasting cholesterol levels have been modest, but grain fibers also show variable effects. New biomarkers are needed to link the physiological functions of specific fibers with long-term health benefits.

A Review of the Role of Soluble Fiber in Health with Specific Reference to Wheat Dextrin

Dietary fiber is widely recognized to have a beneficial role in overall health, but only at adequate levels (25 − 38 g/day for healthy adults). Wheat dextrin in particular is a soluble fiber that can easily be added to the diet and is widely used in the food industry. There is some debate about whether increased intake of soluble fibers leads to health benefits. This paper reviews the evidence regarding the physiological effects and potential health benefits of the addition of soluble dietary fibers, with specific reference to wheat dextrin, based on a search of PubMed. The evidence suggests that soluble fibers help to regulate the digestive system, may increase micronutrient absorption, stabilize blood glucose and lower serum lipids, may prevent several gastrointestinal disorders, and have an accepted role in the prevention of cardiovascular disease. It is concluded that supplementation with soluble fibers (e.g. wheat dextrin) may be useful in individuals at risk of a lower than recommended dietary fiber intake.

An integrated procedure for the measurement of total dietary fibre (including resistant starch), non-digestible oligosaccharides and available carbohydrates

A method is described for the measurement of dietary fibre, including resistant starch (RS), non-digestible oligosaccharides (NDO) and available carbohydrates. Basically, the sample is incubated with pancreatic alpha-amylase and amyloglucosidase under conditions very similar to those described in AOAC Official Method 2002.02 (RS). Reaction is terminated and high molecular weight resistant polysaccharides are precipitated from solution with alcohol and recovered by filtration. Recovery of RS (for most RS sources) is in line with published data from ileostomy studies. The aqueous ethanol extract is concentrated, desalted and analysed for NDO by high-performance liquid chromatography by a method similar to that described by Okuma (AOAC Method 2001.03), except that for logistical reasons, D-sorbitol is used as the internal standard in place of glycerol. Available carbohydrates, defined as D-glucose, D-fructose, sucrose, the D-glucose component of lactose, maltodextrins and non-resistant starch, are measured as D-glucose plus D-fructose in the sample after hydrolysis of oligosaccharides with a mixture of sucrase/maltase plus beta-galactosidase.

A review of the clinical toleration studies of polydextrose in food

Polydextrose is a non-digestible 1 kcal/g polysaccharide used primarily as a sugar replacer and dietary fiber in foods. At typical use levels, polydextrose provides physiological effects similar to those of other dietary fibers. However, excessive consumption of non-digestible carbohydrates can lead to gastrointestinal distress. Nine clinical studies were conducted with polydextrose to evaluate the extent of such symptoms. These studies determined laxation endpoints in adults and children, and showed that polydextrose was better tolerated than most other low digestible carbohydrates (e.g. polyols). This is because of a higher molecular weight and partial colonic fermentation, leading to a lower risk of osmotic diarrhea. After evaluating these studies, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the European Commission Scientific Committee for Food (EC/SCF) concluded that polydextrose has a mean laxative threshold of approximately 90 g/d (1.3 g/kg bw) or 50 g as a single dose.

Studies on the effects of polydextrose intake on physiologic functions in Chinese people

BACKGROUND

Previous studies showed that polydextrose has physiologic effects similar to those of dietary fiber.

OBJECTIVE

Ingestion of 4, 8, and 12 g polydextrose/d was studied to determine the physiologic effects in Chinese subjects.

DESIGN

In a placebo-controlled, randomized, double-blind study, we evaluated the effects of polydextrose ingestion on clinical biochemistry indexes, glycated hemoglobin, glucose tolerance, the glycemic index, bowel function, stool weight and pH, short-chain fatty acid production, fecal microflora, and cecal mucosa cell proliferation.

RESULTS

Polydextrose had no significant effect on blood biochemistry indexes. Ingestion of 12 g polydextrose plus 50 g glucose resulted in a glycemic index of 89% (compared with a glycemic index of 100% after ingestion of 50 g glucose). Bowel function (frequency and ease of defecation) improved significantly and there were no reports of abdominal distention, abdominal cramps, diarrhea, or hypoglycemia. Fecal weight (wet and dry) increased and fecal pH decreased proportionally to polydextrose intake. Short-chain fatty acid production-notably that of butyrate, isobutyrate, and acetate-increased with polydextrose ingestion. There were substantial changes in fecal anaerobes after polydextrose intake. BACTEROIDES: species (B. fragilis, B. vulgatus, and B. intermedius) decreased, whereas LACTOBACILLUS: and BIFIDOBACTERIUM: species increased. The cecal mucosa whole-crypt labeling index increased, with colonocyte proliferation mainly occurring in base compartments, which provided an indirect confirmation of butyrate production in the colon.

CONCLUSION

Polydextrose ingestion had significant dietary fiber-like effects with no laxative problems.