Digestion and absorption in the human intestine of three sugar alcohols

Health effects of synthetic additives and the substitution potential of plant-based additives

The growth of the world population and the rapid industrialization of food have led to food producers' increased reliance on food additives. While food additives offer numerous conveniences and advantages in food applications, the potential risks associated with synthetic additives remain a significant concern. This report examines the current status of safety assessment and toxicity studies of common synthetic additives, including flavorings (sweeteners and flavor enhancers), colorants, preservatives (antimicrobials and antioxidants), and emulsifiers. The report also examines recent advances in promising plant-based alternative additives in terms of active ingredients, sensory properties, potential health benefits, food application challenges, and their related technologies (edible coatings/films and nanoencapsulation technologies), providing valuable references and insights for the sustainable development of food additives.

Strategies for Producing Low FODMAPs Foodstuffs: Challenges and Perspectives

In recent years, there has been a growing interest in a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) as a promising therapeutic approach to reduce the symptoms associated with irritable bowel syndrome (IBS). Hence, the development of low FODMAPs products is an important challenge for the food industry, and among the various foodstuffs associated with the intake of FODMAPs, cereal-based products represent an issue. In fact, even if their content in FODMAPs is limited, their large use in diet can be an important factor in developing IBS symptoms. Several useful approaches have been developed to reduce the FODMAPs content in processed food products. Accurate ingredient selection, the use of enzymes or selected yeasts, and the use of fermentation steps carried out by specific lactic bacteria associated with the use of sourdough represent the technical approaches that have been investigated, alone or in combination, to reduce the FODMAPs content in cereal-based products. This review aims to give an overview of the technological and biotechnological strategies applicable to the formulation of low-FODMAPs products, specifically formulated for consumers affected by IBS. In particular, bread has been the foodstuff mainly investigated throughout the years, but information on other raw or processed products has also been reported. Furthermore, taking into account the required holistic approach for IBS symptoms management, in this review, the use of bioactive compounds that have a positive impact on reducing IBS symptoms as added ingredients in low-FODMAPs products is also discussed.

The metabolic footprint of Clostridia and Erysipelotrichia reveals their role in depleting sugar alcohols in the cecum

BACKGROUND

The catabolic activity of the microbiota contributes to health by aiding in nutrition, immune education, and niche protection against pathogens. However, the nutrients consumed by common taxa within the gut microbiota remain incompletely understood.

METHODS

Here we combined microbiota profiling with an un-targeted metabolomics approach to determine whether depletion of small metabolites in the cecum of mice correlated with the presence of specific bacterial taxa. Causality was investigated by engrafting germ-free or antibiotic-treated mice with complex or defined microbial communities.

RESULTS

We noted that a depletion of Clostridia and Erysipelotrichia from the gut microbiota triggered by antibiotic treatment was associated with an increase in the cecal concentration of sugar acids and sugar alcohols (polyols). Notably, when we inoculated germ-free mice with a defined microbial community of 14 Clostridia and 3 Erysipelotrichia isolates, we observed the inverse, with a marked decrease in the concentrations of sugar acids and polyols in cecal contents. The carbohydrate footprint produced by the defined microbial community was similar to that observed in gnotobiotic mice receiving a cecal microbiota transplant from conventional mice. Supplementation with sorbitol, a polyol used as artificial sweetener, increased cecal sorbitol concentrations in antibiotic-treated mice, which was abrogated after inoculation with a Clostridia isolate able to grow on sorbitol in vitro.

CONCLUSIONS

We conclude that consumption of sugar alcohols by Clostridia and Erysipelotrichia species depletes these metabolites from the intestinal lumen during homeostasis. Video abstract.

Assessment of Carbohydrate Availability, Fermentability, and Food Energy Value in Humans Using Measurements of Breath Hydrogen

Measurements in humans of their breath hydrogen is sometimes used to assess the availability, fermentability, and food energy value of carbohydrates that, to an unknown extent, resists small intestinal digestion and fermentation in the large intestine. Here I outline that the method is utterly flawed and conclude that it is unsuitable for making claims as to the availability, fermentability, and food energy value of carbohydrates. More traditional methods, although more demanding of time and effort, can be used. Otherwise further development of methodology is essential to avoid undue risk of bias.

A mathematical model of food intake

The metabolic, hormonal and psychological determinants of the feeding behavior in humans are numerous and complex. A plausible model of the initiation, continuation and cessation of meals taking into account the most relevant such determinants would be very useful in simulating food intake over hours to days, thus providing input into existing models of nutrient absorption and metabolism. In the present work, a meal model is proposed, incorporating stomach distension, glycemic variations, ghrelin dynamics, cultural habits and influences on the initiation and continuation of meals, reflecting a combination of hedonic and appetite components. Given a set of parameter values (portraying a single subject), the timing and size of meals are stochastic. The model parameters are calibrated so as to reflect established medical knowledge on data of food intake from the National Health and Nutrition Examination Survey (NHANES) database during years 2015 and 2016.

Maltitol: Analytical Determination Methods, Applications in the Food Industry, Metabolism and Health Impacts

Bulk sweetener maltitol belongs to the polyols family and there have been several dietary applications in the past few years, during which the food industry has used it in many food products: bakery and dairy products, chocolate, sweets. This review paper addresses and discusses in detail the most relevant aspects concerning the analytical methods employed to determine maltitol's food safety and industry applications, its metabolism and its impacts on human health. According to our main research outcome, we can assume that maltitol at lower doses poses little risk to humans and is a good alternative to using sucrose. However, it causes diarrhoea and foetus complications at high doses. Regarding its determination, high-performance liquid chromatography proved the primary method in various food matrices. The future role of maltitol in the food industry is likely to become more relevant as processors seek alternative sweeteners in product formulation without compromising health.

A Systematic Review of the Effects of Polyols on Gastrointestinal Health and Irritable Bowel Syndrome

Polyols are sugar alcohols found in certain fruits, vegetables, and sugar-free sweeteners. They make up a component of the diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, which is gaining popularity in the treatment of patients with irritable bowel syndrome (IBS). We conducted a systematic review to evaluate the effects of polyols on the gastrointestinal tract in healthy men and women and in patients with IBS. Utilizing PubMed, Ovid, and Embase databases, we conducted a search on individual polyols and each of these terms: fermentation, absorption, motility, permeability, and gastrointestinal symptoms. Standard protocols for a systematic review were followed. We found a total of 1823 eligible articles, 79 of which were included in the review. Overall, available work has shown that polyol malabsorption generally occurs in a dose-dependent fashion in healthy individuals, and malabsorption increases when polyols are ingested in combination. However, studies in patients with IBS have shown conflicting results pertaining to polyol malabsorption. Polyol ingestion can lead to intestinal dysmotility in patients with IBS. Regarding the microbiome, moderate doses of polyols have been shown to shift the microbiome toward an increase in bifidobacteria in healthy individuals and may therefore be beneficial as prebiotics. However, data are limited regarding polyols and the microbiome in patients with IBS. Polyols can induce dose-dependent symptoms of flatulence, abdominal discomfort, and laxative effects when consumed by both healthy volunteers and patients with IBS. Further research is needed to better understand the effects of specific polyols on gastrointestinal function, sensation, and the microbiome in health and gastrointestinal disorders such as IBS.

Gastrointestinal Disturbances Associated with the Consumption of Sugar Alcohols with Special Consideration of Xylitol: Scientific Review and Instructions for Dentists and Other Health-Care Professionals

Sugar alcohols (polyols) are used in food manufacturing and in medical tests and examinations. d-Glucitol (sorbitol) and d-mannitol were previously the most common alditols used for these purposes. After the 1960s, xylitol became a common ingredient in noncariogenic confectioneries, oral hygiene products, and diabetic food. Erythritol, a polyol of the tetritol type, can be regarded as the sweetener of the "next generation." The disaccharide polyols maltitol, lactitol, and isomalt have also been used in food manufacturing and in medical tests. Consumption of pentitol- and hexitol-type polyols and disaccharide polyols may cause gastrointestinal disturbances at least in unaccustomed subjects. The occurrence of disturbances depends on consumer properties and on the molecular size and configuration of the polyol molecule. Adaptation may take place as a result of enzyme induction in the intestinal flora. Some of the literature on xylitol has been difficult to access by health-care professionals and will be reviewed here. Research and clinical field experience have found no pathology in polyol-associated osmotic diarrhea-the intestinal mucosa having normal basic structure, except in extreme instances. Xylitol is better tolerated than hexitols or the disaccharide polyols. Erythritol, owing to its smaller molecular weight and configuration that differ from other alditols, normally avoids the gastrointestinal reactions encountered with other polyols. This review will also touch upon the FODMAPs diet concept.

Role of FODMAPs in Patients With Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a condition characterized by abdominal pain, bloating, flatus, and altered bowel habits. The role of dietary components in inducing IBS symptoms is difficult to explore. To date, foods are not considered a cause but rather symptom-triggering factors. Particular interest has been given to the so-called FODMAPs (fermentable oligo-, di-, and monosaccharides and polyols). We aimed to summarize the evidence from the most common approaches to manage suspected food intolerance in IBS, with a particular interest in the role of FODMAPs and the effects of a low FODMAP diet. We reviewed literature, consulting PubMed and Medline by using the search terms FODMAP(s), fructose, lactose, fructans, galactans, polyols (sorbitol, mannitol, maltitol, xylitol, erythritol, polydextrose, and isomalt), irritable bowel syndrome, and functional gastrointestinal symptoms. FODMAP-restricted diets have been used for a long time to manage patients with IBS. The innovation in the so-called FODMAP concept is that a global restriction should have a more consistent effect than a limited one in preventing abdominal distension. Even though all the potential low FODMAP diets provide good relief of symptoms in many patients, there is just a little relief in others. Several studies highlight the role of low FODMAP diets to improve symptoms in patients with IBS. The evidence on this dietary approach supports the hypothesis that a low FODMAP diet should be the first dietary approach. However, many points remain to be clarified, including the evaluation of possibly significant nutrition concerns.

Fermentable oligosaccharides, disaccharides, monosaccharides and polyols: role in irritable bowel syndrome

Irritable bowel syndrome (IBS) was previously left poorly treated despite its high prevalence and cost. Over the past decade, significant research has been conducted providing new dietary strategies for IBS management. The 'low fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet' has shown symptom improvement in 68-76% of patients. Randomized, controlled trials have now proven its efficacy. The diet, low in poorly absorbed and fermentable carbohydrates, uses dietary restriction and re-challenge to determine individual tolerance to various short-chain carbohydrates. However there may be potential detrimental effects of the diet in the long term, due to potential changes to the gastrointestinal microbiota. Appropriate dietary education and management of the diet is imperative. Future research should focus on the relevance of changes to the microbiota and ways to liberalize the dietary restrictions.

Dietary sorbitol and mannitol: food content and distinct absorption patterns between healthy individuals and patients with irritable bowel syndrome

BACKGROUND

Sorbitol and mannitol are naturally-occurring polyol isomers. Although poor absorption and induction of gastrointestinal symptoms by sorbitol are known, the properties of mannitol are poorly described. We aimed to expand data on food composition of these polyols, and to compare their absorptive capacities and symptom induction in patients with irritable bowel syndrome (IBS) and healthy individuals.

METHODS

Food samples were analysed for sorbitol and mannitol content. The degree of absorption measured by breath hydrogen production and gastrointestinal symptoms (visual analogue scales) was evaluated in a randomised, double-blinded, placebo-controlled study in 21 healthy and 20 IBS subjects after challenges with 10 g of sorbitol, mannitol or glucose.

RESULTS

Certain fruits and sugar-free gum contained sorbitol, whereas mannitol content was higher in certain vegetables. Similar proportions of patients with IBS (40%) and healthy subjects (33%) completely absorbed sorbitol, although more so with IBS absorbed mannitol (80% versus 43%; P = 0.02). Breath hydrogen production was similar in both groups after lactulose but was reduced in patients with IBS after both polyols. No difference in mean (SEM) hydrogen production was found in healthy controls after sorbitol [area-under-the-curve: 2766 (591) ppm 4 h(-1) ] or mannitol [2062 (468) ppm 4 h(-1) ] but, in patients with IBS, this was greater after sorbitol [1136 (204) ppm 4 h(-1) ] than mannitol [404 (154) ppm 4 h(-1) ; P = 0.002]. Overall gastrointestinal symptoms increased significantly after both polyols in patients with IBS only, although they were independent of malabsorption of either of the polyols.

CONCLUSIONS

Increased and discordant absorption of mannitol and sorbitol occurs in patients with IBS compared to that in healthy controls. Polyols induced gastrointestinal symptoms in patients with IBS independently of their absorptive patterns, suggesting that the dietary restriction of polyols may be efficacious.

Acute glycemic and blood lipid response to the ingestion of a candy bar–like protein supplement compared with its candy bar counterpart

Candy bar–like protein supplements are sometimes consumed for their sugar alcohol content, which lowers the glycemic response. The purpose of this study was to determine the acute glycemic and blood lipid response to the ingestion of a candy bar–like protein supplement compared with its candy bar counterpart. In a crossover design, 5 males and 5 females (N = 10; age, 24 ± 5.5 years; height, 174 ± 8.3 cm; weight, 80 ± 21.9 kg) consumed a candy bar (CBR) or a similar protein bar (PBR) after a 10-h fast. Blood draws occurred at baseline and at 15, 30, 45, and 60 min after consumption and were analyzed for blood glucose, insulin, and lipid profiles. A 2×5 ANOVA was used, with Student's t tests for significant interactions. A significant (p < 0.05) blood glucose time effect occurred in both groups, with a more profound glucose response from the CBR at 15 min (CBR: 6.2 ± 0.8 mmol·L−1; PBR: 4.9 ± 0.5 mmol·L−1). Triglycerides increased significantly (p < 0.05), independent of group, peaking at 60 min (Δ CBR: 0.8 ± 0.3 mmol·L−1; Δ PBR: 1.3 ± 0.3 mmol·L−1). Insulin increased significantly (p < 0.05), independent of group, peaking at 15 min (Δ CBR: 42 ± 27 μIU·mL−1; Δ PBR: 25 ± 11 μIU·mL−1). No significant change (p > 0.05) was observed in total cholesterol. Blood glucose, triglycerides, and insulin all increased significantly in response to both CBR and PBR consumption. The CBR elicited a greater effect on blood glucose; however, the PBR had a strong impact on serum triglycerides and insulin.

Short-term digestive tolerance of chocolate formulated with maltitol in children

INTRODUCTION

Polyols are molecules of interest for food industries because of their technological and nutritional properties. Maltitol is known for its non-acidogenic and low-energetic properties. Our primary objective was to evaluate the digestive tolerance of maltitol in children. The secondary objective was to compare the organoleptic properties of maltitol and sucrose in chocolate.

METHOD

Healthy children were included in a double-blind, randomized parallel study versus placebo. The subjects received one dose of either maltitol or sucrose chocolate per week. Increasing doses were tested from 5 to 15 g maltitol in chocolate. Abdominal pain, rumbling, bloating and flatulence scores were evaluated using visual analog scales.

RESULTS

Some statistical differences on intestinal parameters were observed in the maltitol group compared with placebo, mainly concerning flatulence scores. Nevertheless, these scores remained low and could be considered minor.

CONCLUSION

Our results suggest that maltitol was well tolerated in children at 15 g in one intake.

Scientific Opinion on the use of Polyglycitol Syrup as a food additive

Following a request from the European Commission (EC), the Panel on Food Additives and Nutrient Sources added to Food (ANS) was asked to deliver a scientific opinion on the safety of polyglycitol syrup when used as a food additive. Polyglycitol syrup belongs to the hydrogenated starch hydrolysate syrups composed of maltitol, sorbitol and higher molecular weight polyols. In contrast to maltitol syrup EU specifications, the polyglycitol syrup has a defined concentration of sorbitol, a lower concentration of maltitol and a defined concentration of higher molecular weight polyols. Consequently, it is not covered by specifications for maltitol syrup which is an EU authorised food additive. In humans, the main reported adverse effect specifically associated with polyglycitol syrup exposure was gastric disturbance. The Panel considers that conservative estimates of the exposure to polyglycitol syrup, for consumer-only and the general population, arising from the proposed uses and use-levels, are close to, and for children even higher than, doses associated with gastric disturbances when administered as bolus doses in human trials and as reported in recent case reports.

Gastrointestinal effects of low-digestible carbohydrates

Low-digestible carbohydrates (LDCs) are carbohydrates that are incompletely or not absorbed in the small intestine but are at least partly fermented by bacteria in the large intestine. Fiber, resistant starch, and sugar alcohols are types of LDCs. Given potential health benefits (including a reduced caloric content, reduced or no effect on blood glucose levels, non-cariogenic effect) the prevalence of LDCs in processed foods is increasing. Many of the benefits of LDCs are related to the inability of human digestive enzymes to break down completely the carbohydrates into absorbable saccharides and the subsequent fermentation of unabsorbed carbohydrates in the colon. As a result, LDCs may affect laxation and cause gastrointestinal effects, including abdominal discomfort, flatus, and diarrhea, especially at higher or excessive intakes. Such responses, though transient, affect the perception of the well-being of consumers and their acceptance of food products containing LDCs. Current recommendations for fiber intake do not consider total LDC consumption nor recommend an upper limit for LDC intake based on potential gastrointestinal effects. Therefore, a review of published studies reporting gastrointestinal effects of LDCs was conducted. We included only studies published in refereed journals in English. Additionally, we excluded studies of subjects with incomplete or abnormal functioning gastrointestinal tracts or where antibiotics, stimulant laxatives, or other drugs affecting motility were included. Only in studies with a control period, either placebo treatment or no LDC treatment, were included. Studies must have included an acceptable measure of gastrointestinal effect. Sixty-eight studies and six review articles were evaluated. This review describes definitions, classifications, and mechanisms of LDCs, evaluates published human feeding studies of fifteen LDCs for associations between gastrointestinal effects and levels of LDC intake, and presents recommendations for LDC consumption and further research.

Health potential of polyols as sugar replacers, with emphasis on low glycaemic properties

Abstract Polyols are hydrogenated carbohydrates used as sugar replacers. Interest now arises because of their multiple potential health benefits. They are non-cariogenic (sugar-free tooth-friendly), low-glycaemic (potentially helpful in diabetes and cardiovascular disease), low-energy and low-insulinaemic (potentially helpful in obesity), low-digestible (potentially helpful in the colon), osmotic (colon-hydrating, laxative and purifying) carbohydrates. Such potential health benefits are reviewed. A major focus here is the glycaemic index (GI) of polyols as regards the health implications of low-GI foods. The literature on glycaemia and insulinaemia after polyol ingestion was analysed and expressed in the GI and insulinaemic index (II) modes, which yielded the values: erythritol 0, 2; xylitol 13, 11; sorbitol 9, 11; mannitol 0, 0; maltitol 35, 27; isomalt 9, 6; lactitol 6, 4; polyglycitol 39, 23. These values are all much lower than sucrose 65, 43 or glucose 100, 100. GI values on replacing sucrose were independent of both intake (up to 50 g) and the state of carbohydrate metabolism (normal, type 1 with artificial pancreas and type 2 diabetes mellitus). The assignment of foods and polyols to GI bands is considered, these being: high (> 70), intermediate (> 55–70), low (> 40–55), and very low (< 40) including non-glycaemic; the last aims to target particularly low-GI-carbohydrate-based foods. Polyols ranged from low to very low GI. An examination was made of the dietary factors affecting the GI of polyols and foods. Polyol and other food GI values could be used to estimate the GI of food mixtures containing polyols without underestimation. Among foods and polyols a departure of II from GI was observed due to fat elevating II and reducing GI. Fat exerted an additional negative influence on GI, presumed due to reduced rates of gastric emptying. Among the foods examined, the interaction was prominent with snack foods; this potentially damaging insulinaemia could be reduced using polyols. Improved glycated haemoglobin as a marker of glycaemic control was found in a 12-week study of type 2 diabetes mellitus patients consuming polyol, adding to other studies showing improved glucose control on ingestion of low-GI carbohydrate. In general some improvement in long-term glycaemic control was discernible on reducing the glycaemic load via GI by as little as 15–20 g daily. Similar amounts of polyols are normally acceptable. Although polyols are not essential nutrients, they contribute to clinically recognised maintenance of a healthy colonic environment and function. A role for polyols and polyol foods to hydrate the colonic contents and aid laxation is now recognised by physicians. Polyols favour saccharolytic anaerobes and aciduric organisms in the colon, purifying the colon of endotoxic, putrefying and pathological organisms, which has clinical relevance. Polyols also contribute towards short-chain organic acid formation for a healthy colonic epithelium. Polyol tooth-friendliness and reduced energy values are affirmed and add to the potential benefits. In regard to gastrointestinal tolerance, food scientists and nutritionists, physicians, and dentists have in their independent professional capacities each now described sensible approaches to the use and consumption of polyols.

Suppressive effect of partially hydrolyzed guar gum on transitory diarrhea induced by ingestion of maltitol and lactitol in healthy humans

OBJECTIVES

To estimate the suppressive effect of partially hydrolyzed guar gum (PHGG) on transitory diarrhea induced by ingestion of a sufficient amount of maltitol or lactitol in female subjects.

DESIGN

The first, the minimal dose level of maltitol and lactitol that would induce transitory diarrhea was estimated separately for each subject. Individual subject was administered a dose that increased by 5 g stepwise from 10 to 45 g until diarrhea was experienced. Thereafter, the suppressive effect on diarrhea was observed after each subject ingested a mixture of 5 g of PHGG and the minimal dose level of maltitol or lactitol.

SETTING

Laboratory of Public Health Nutrition, Department of Nutrition and Health Sciences, Siebold University of Nagasaki.

SUBJECTS

Thirty-four normal female subjects (21.3+/-0.9 years; 49.5+/-5.3 kg).

MAIN OUTCOME MEASUREMENT

Incidence of diarrhea caused by the ingestion of maltitol or lactitol and the ratio of suppression achieved by adding PHGG for diarrhea.

RESULTS

The ingestion of amounts up to 45 g of maltitol, diarrhea caused in 29 of 34 subjects (85.3%), whereas the ingestion of lactitol caused diarrhea in 100%. The diarrhea owing to maltitol was improved in 10 of 28 subjects by the addition of 5 g of PHGG to minimal dose-induced diarrhea, and that owing to lactitol was in seven of 19 subjects. Adding 10 g of PHGG strongly suppressed the diarrhea caused by maltitol, and the cumulative ratio was 82.1% (23/28).

CONCLUSION

The transitory diarrhea caused by the ingestion of maltitol or lactitol was clearly suppressed by the addition of PHGG. These results strongly suggest that diarrhea caused by the ingestion of a sufficient amount of non-digestible sugar substitute can be suppressed by the addition of dietary fiber.

Threshold for Transitory Diarrhea Induced by Ingestion of Xylitol and Lactitol in Young Male and Female Adults

The ingestion of a sufficiently large amount of non-digestible and/or non-absorbable sugar substitutes causes overt diarrhea. The objective is to estimate the non-effective dosage that does not cause transitory diarrhea for xylitol, lactitol, and erythritol in healthy subjects. Twenty-seven males and 28 females gave informed and written consent to participate, were selected, and participated in the study. The oral dose levels of xylitol were 10, 20, 30, 40 and 50 g, while those of lactitol were 10, 20, 30, and 40 g. Those of erythritol were 20, 30, 40 and 50 g. The test substance was ingested in 150 mL of water 2-3 h after a meal. The ingestion order progressed from the smallest to larger amounts, and stopped at the dose that caused diarrhea, or at the largest dose level to be set up. The non-effective dose level of xylitol was 0.37 g/kg B.W. for males and 0.42 g/kg B.W. for females. That of lactitol was 0.25 g/kg B.W. for males and 0.34 g/kg B.W. for females, and that of erythritol was 0.46 g/kg B.W. for males and 0.68 g/kg B.W. for females. These results appear reasonable, because xylitol is poorly absorbed from the small intestine, and the absorption rate is less than that of erythritol, while lactitol is not hydrolyzed. Non-digestible and/or non-absorbable sugar alcohols and oligosaccharides with beneficial health effects inevitably cause overt diarrhea. The estimation of the non-effective dose level of these sugar substitutes is essential and important to produce processed foods that the consumer can use safely and with confidence.

Sorbitol-based osmotic diarrhea: Possible causes and mechanism of prevention investigated in rats

AIM: To study the possible causes of sorbitol (S)-based diarrhea and its mechanism of reduction by rice gruel (RG) in cecectomized rats.

METHODS: S was dissolved either in distilled water or in RG (50 g/L) and ingested as a single oral dose (1.2 g/kg body mass, containing 0.5 g/L phenol red as a recovery marker) by S (control) and S + RG groups (n = 7), respectively. This dose is over the laxative dose for humans. Animals were sacrificed exactly 1 h after dose ingestion, without any access to drinking water. The whole gastro-intestinal tract was divided into seven segments and sampled to analyze the S and marker remaining in its contents.

RESULTS: Gastric-emptying and intestinal transit were comparatively slower in the S + RG group. Also, the S absorption index in the 3^rd and last quarter of the small intestine (24.85 ± 18.88% vs 0.0 ± 0.0% and 39.09 ± 32.75% vs 0.0 ± 0.0%, respectively, P < 0.05) was significantly higher in the S + RG group than in the control group. The S absorption index and the intestinal fluid volume are inversely related to each other.

CONCLUSION: The intestinal mal-absorption of S is the main reason for S-based osmotic diarrhea. Where RG enhanced the absorption of S through passive diffusion, the degree of diarrhea was reduced in cecectomized rats.

Effects of an osmotically active agent on colonic transit

It is unknown if sorbitol, a widely used laxative agent, accelerates colonic transit, and if these effects are modified by concomitant meal ingestion. Colonic transit was assessed by (111)In scintigraphy in 40 healthy subjects. After a 24-h scan, subjects received sorbitol (30 mL of 70% solution) or dextrose (30 mL of 70% solution), administered with or without a meal. Colonic transit, breath hydrogen excretion, and symptom scores were recorded for 4 h thereafter. VAS scores for flatulence, but not other symptoms increased (P = 0.004) by 13.1 +/- 6.3 mm (mean +/- SEM) on a 100 mm scale after sorbitol alone or sorbitol with a meal (by 18.9 +/- 7.2 mm), but not after dextrose. After adjusting for GC(24), sorbitol accelerated (P < 0.001) colonic transit (GC(28) = 3.0 +/- 0.3) compared with dextrose (GC(28) = 2.2 +/- 0.2), regardless of meal ingestion. Breath hydrogen excretion was correlated with the change in colonic transit (r = 0.52, P < 0.01) and with flatulence (r = 0.45, P = 0.003) after sugar ingestion. In healthy subjects, sorbitol accelerated colonic transit and increased flatulence but not other symptoms within 4 h, regardless of meal intake.

Personal view: food for thought--western lifestyle and susceptibility to Crohn's disease. The FODMAP hypothesis

Susceptibility to the development of Crohn's disease involves a combination of genetic and environmental factors. The association of Crohn's disease with westernization has implicated lifestyle factors in pathogenesis. While diet is a likely candidate, evidence for specific changes in dietary habits and/or intake has been lacking. A new hypothesis is proposed, by which excessive delivery of highly fermentable but poorly absorbed short-chain carbohydrates and polyols (designated FODMAPs--Fermentable Oligo-, Di- and Mono-saccharides And Polyols) to the distal small intestinal and colonic lumen is a dietary factor underlying susceptibility to Crohn's disease. The subsequent rapid fermentation of FODMAPs in the distal small and proximal large intestine induces conditions in the bowel that lead to increased intestinal permeability, a predisposing factor to the development of Crohn's disease. Evidence supporting this hypothesis includes the increasing intake of FODMAPs in western societies, the association of increased intake of sugars in the development of Crohn's disease, and the previously documented effects of the ingestion of excessive FODMAPs on the bowel. This hypothesis provides potential for the design of preventive strategies and raises concern about current enthusiasm for putative health-promoting effects of FODMAPs. One of the greatest challenges in defining the pathogenesis of Crohn's disease is to identify predisposing environmental factors. Such an achievement might lead to the development of preventive strategies for, and the definition of, possible target for changing the natural history of this serious disease. The present paper describes a new hypothesis for one such environmental factor.

Effect of sugar alcohols on gut function and body composition in normal and cecectomized rats

The effects of two sugar alcohols on feed utilization, digesta retention, gut fermentation and serum lipid profiles were compared in normal and cecectomized rats to examine the possibility of the cecectomized rat as an experimental animal with relevance to humans. Semi-purified diets containing no sugar alcohol, 7% sorbitol or 7% lactitol were fed to normal and cecectomized rats for 16 days. The digestibility of the crude fat and the compositions of the carcass dry matter and crude fat were significantly decreased by feeding sugar alcohols in both groups, but the effects were relatively higher in the cecectomized rats than in the normal rats. Diarrhea, faster transit times and shorter retention times of digesta were noted in the cecectomized rats fed sugar alcohols, while the inverse results were observed in the normal rats fed similar diets. The concentration of cecal organic acids was increased in the normal rats, whereas the concentration of colonic organic acids was decreased in the cecectomized rats fed sugar alcohols, compared with their corresponding control groups. The concentration of serum total cholesterol was decreased in both the normal and cecectomized rats fed diets containing sugar alcohols. The tendencies for diarrhea, faster digesta transit and reduced body fat induced by the fermentable materials in the cecectomized rat have good relevance to the parallel effects of fermentable materials in humans, suggesting the possibility of using the cecectomized rat as a model to study some of the physiological effects of sugar alcohols in humans.

Microbial-gut interactions in health and disease. Antibiotic-associated diarrhoea

Most cases of antibiotic-associated diarrhoea (AAD) are directly or indirectly due to the alteration of gut microflora by antibiotics. 'Functional' diarrhoea, usually limited to a mild and brief change in stool frequency, is considered as the most frequent pattern of AAD. Reduced carbohydrate fermentation and impaired metabolism of bile acids have been claimed as the potential causes of this transient digestive discomfort but a critical analysis of the data supporting these theories is necessary. Alternatively, changes in the gut flora ecosystem allow pathogens to proliferate. Clostridium difficile is responsible for approximately 10% of cases of AAD and almost all cases of antibiotic-associated pseudomembranous colitis. The level of evidence which supports the potential responsibility of other candidate pathogens (Klebsiella oxytoca, enterotoxin-producing Clostridium perfringens and Staphylococcus aureus, Candida) needs to be appreciated according to the updated postulates of causality relationships between a bacterium and a disease.

A digestive tolerance study of maltitol after occasional and regular consumption in healthy humans

AIM

We aimed to evaluate the gastro-intestinal tolerance to an indigestible bulking sweetener containing sugar alcohol using a double-blind random cross-over study.

METHOD

In order to simulate their usual pattern of consumption, 12 healthy volunteers ingested maltitol or sucrose throughout the day, either occasionally (once a week for each sugar, first period) or regularly (every day for two 9 day periods, second period). In both patterns of consumption, daily sugar doses were increased until diarrhea and/or a grade 3 (ie severe) digestive symptom occurred, at which the dose level was defined as the threshold dose (TD).

RESULTS

In the first period (occasional consumption), the mean TD was 92+/-6 g with maltitol and 106+/-4 g with sucrose (P=0.059). The mean intensity of digestive symptoms was 1.1 and 1.3, respectively (P=NS). Diarrhea appeared in six and one subjects respectively (P=0.035). In the second period (regular consumption), the mean TD was 93+/-9 g with maltitol and 113+/-7 g with sucrose (P=0.008). The mean intensity of digestive symptoms was 1.7 and 1.2, respectively (P=NS). However, diarrhea appeared in eight and three subjects, respectively (P=0.04). Maltitol and sucrose TDs between the two periods were not different.

CONCLUSIONS

Under our experimental conditions, in comparison to sucrose: (a) occasional or regular consumption of maltitol is not associated with severe digestive symptoms; (b) in both patterns of maltitol consumption, diarrhea frequency is higher, but it appeared only for very high doses of maltitol, much greater than those currently used; (c) maltitol does not lead to intestinal flora adaptation after a 9 day period of consumption.

Nutritional aspects of short-chain fructooligosaccharides: natural occurrence, chemistry, physiology and health implications

Short-chain fructooligosaccharides occur in a number of edible plants, such as chicory, onions, asparagus, wheat... They are a group of linear fructose oligomers with a degree of polymerisation ranging from n = 1 up to 5 (oligosaccharides). Short-chain fructooligosaccharides, to a large extent, escape digestion in the human upper intestine and reach the colon where they are totally fermented mostly to lactate, short chain fatty acids (acetate, propionate and butyrate), and gas, like dietary fibres. As a consequence of their fermentation, their caloric value is approximately 2 Kcal/g. A faecal bulking effect of fructooligosaccharides has been observed in humans. An important property of short-chain fructooligosaccharides is the stimulation of bifidobacterial growth specifically while suppressing the growth of potentially harmful species such as, for example, Clostridium perfringens in the colon. It is associated with a decrease in faecal pH, an increase in faecal or colonic organic acids, a decrease in the production of nitrogenous end products in urine and stools, a decrease in faecal bacterial enzymatic activities and a modification in faecal neutral sterols. The short-chain fructooligosaccharides enhance magnesium absorption in humans and have been shown, in animal models, to reduce colon tumour development by enhancing both colon butyrate concentrations and local immune system effectors.

The comparative gastrointestinal responses of children and adults following consumption of sweets formulated with sucrose, isomalt and lycasin HBC

OBJECTIVES

To determine the gastrointestinal responses of children and adults following consumption of sucrose, isomalt and lycasin HBC and to compare these at two different dose levels in adults.

DESIGN

Both studies were randomised, double-blind, cross-over designs.

SUBJECTS

Fifty-one children aged 6-9 y were recruited from primary schools in the Salford area of Greater Manchester. Forty-eight children completed the study. Fifty healthy adult volunteers aged 18-24 y were recruited from the student population of the University of Salford. All subjects completed the study.

INTERVENTIONS

Children consumed either 25 g of sucrose, isomalt or lycasin HBC and adults 25 and 40 g in hard boiled sweets per day for two consecutive test days. Test periods of 2 days were separated by 7 day washout periods. Children consumed sweets throughout test days and adults in no less than 30 min but no more than 90 min. Subjects reported the prevalence and magnitude of flatulence, borborygmi, bloating, colic, bowel movements and watery faeces.

RESULTS

Consumption of 25 g isomalt provoked a mild laxative effect in children but not in adults. Consumption of 25 g isomalt significantly increased the prevalence and magnitude of gastrointestinal responses in both children and adults. Consumption of 25 g lycasin HBC significantly increased borborygml in children and adults but no other gastrointestinal responses. Consumption of 40 g lycasin HBC or isomalt by adults significantly increased the mean frequency of bowel movements and the number of subjects passing watery faeces. In adults, 40 g isomalt and lycasin HBC provoked significantly more gastrointestinal responses compared to 25 g of either product.

CONCLUSIONS

Consumption of 25 g lycasin HBC does not provoke an unacceptable laxative effect or gastrointestinal response in children or adults compared to 25 g isomalt, which is associated with a mild laxative effect and increase in gastrointestinal responses. In adults gastrointestinal responses following consumption of products were found to be dose dependent.

Net energy value of two low-digestible carbohydrates, Lycasin HBC and the hydrogenated polysaccharide fraction of Lycasin HBC in healthy human subjects and their impact on nutrient digestive utilization

The metabolizable energy content of low-digestible carbohydrates does not correspond with their true energy value. The aim of the present study was to determine the tolerance and effects of two polyols on digestion and energy expenditure in healthy men, as well as their digestible, metabolizable and net energy values. Nine healthy men were fed for 32 d periods a maintenance diet supplemented either with dextrose, Lycasin HBC (Roquette Frères, Lestrem, France), or the hydrogenated polysaccharide fraction of Lycasin HBC, at a level of 100 g DM/d in six equal doses per d according to a 3 x 3 Latin square design with three repetitions. After a 20 d progressive adaptation period, food intake was determined for 12d using the duplicate meal method and faeces and urine were collected for 10 d for further analyses. Subjects spent 36 h in one of two open-circuit whole-body calorimeters with measurements during the last 24h. Ingestion of the polyols did not cause severe digestive disorders, except excessive gas emission, and flatulence and gurgling in some subjects. The polyols induced significant increases in wet (+45 and +66% respectively, P<0.01) and dry (+53 and +75 % respectively, P<0.002) stool weight, resulting in a 2% decrease in dietary energy digestibility (P<0.001). They resulted also in significant increases in sleeping (+4.1%, P<0.03) and daily energy expenditure (+2.7 and +2.9% respectively, P<0.02) compared with dextrose ingestion. The apparent energy digestibility of the two polyols was 0.82 and 0.79 respectively, their metabolizable energy value averaged 14.1 kJ/g DM, and their net energy value averaged 10.8 kJ/g DM, that is, 35 % less than those of sucrose and starch.

Tolerance to low-digestible carbohydrates: symptomatology and methods

Low-digestible carbohydrates (LDCs) are incompletely or not absorbed in the small bowel and fermented in the colon. They are usually well tolerated but may also have some dose-related undesirable effects due to their natural osmotic potential and/or excessive fermentation: borborygmi, excessive flatus, bloating, abdominal cramps and eventually diarrhoea. There is an important intersubject variability in the tolerance to LDCs because of differences in absorption capacity, motility pattern, colonic response and intestinal sensitivity. There is also a great intrasubject variability, depending on the type of LDC, dosage and type of consumption. Absorption of LDC in the small intestine can be assessed using hydrogen breath test or intubation techniques or analysis of ileostomy effluents. Double-blind, placebo-controlled studies are required to assess the subjective symptoms of intolerance, and the experimental conditions may influence the results.

Tolerance and breath hydrogen excretion following ingestion of maltitol incorporated at two levels into milk chocolate consumed by healthy young adults with and without fasting

Little is known about the gastrointestinal effects of ingesting maltitol in chocolate. This study was designed to determine whether it leads to increased gastrointestinal symptomatology and if that symptomatology is dose related. It was also designed to discover whether breath hydrogen excretion in response to maltitol is dose related. In a double-blind, crossover study, 20 healthy volunteers aged 18-24 y ingested 100 g chocolate containing 40 g sucrose, 10 g sucrose plus 30 g maltitol or 40 g maltitol after fasting (abstinence from food and liquids from 2200 h on the night before chocolate consumption) and not fasting. There was no difference in symptomatology between fasting and nonfasting periods, and consumption order had no effect on symptomatology. Relative to ingestion of sucrose, 30 g maltitol caused no significant difference in symptoms, but 40 g resulted in more mild borborygmi (P < 0.05) and mild flatulence (P < 0.01) but not moderate or severe symptoms. Neither 30 nor 40 g maltitol caused significantly greater laxation than sucrose ingestion (P > 0.05). In a separate study, 10 healthy volunteers aged 18-24 y ate the same test products before breath H2 testing; 40 g maltitol in chocolate caused a greater total breath H2 excretion compared with 30 g maltitol (P < 0.05) or sucrose (P < 0.01). Total breath hydrogen excretion was also greater with 30 g maltitol compared with sucrose (P < 0.05). This dose-related response was consistent with the lower symptomatology after ingestion of 30 vs. 40 g maltitol. We have shown that 30 g maltitol in chocolate causes no significant symptomatology in young adults; however, 40 g caused mild borborygmi and flatus but no increased laxation. An increased breath H2 response indicates colonic fermentation of this polyol.

Glucose does not facilitate the absorption of sorbitol perfused in situ in the human small intestine

Sorbitol is better absorbed in the small intestine when ingested concomitantly with glucose. The aim of this study was to test in situ the effect of glucose on the absorption of sorbitol in the human small intestine, using the perfusion technique. The sorbitol absorption of three test solutions, perfused in a random order, was measured in a 30-cm segment of jejunum in six healthy volunteers (4 males and 2 females). The solutions contained the same concentration of sorbitol (55 mmol/L) and increasing concentrations of D-glucose (0, 55 and 110 mmol/L). Net absorption of water increased as the glucose concentration of the solution increased and differed significantly among the three solutions. Net absorption of glucose was significantly greater for the 110 mmol/L glucose solution than for the 55 mmol/L glucose solution [23.6 +/- 1.8 vs. 11.0 +/- 1.2 mmol/(h x 30 cm), P < 0.01]. Sorbitol absorption in the jejunal segment was 5.2 +/- 1.3, 6.2 +/- 0.5 and 5.8 +/- 0.4 mmol/(h x 30 cm) for the glucose-free solution, the 55 mmol/L glucose solution, and the 110 mmol/L glucose solution, respectively. These values did not differ significantly. These results do not support the hypothesis of a facilitating effect of glucose on sorbitol absorption in the human small intestine.

Effect of glucose and lipids on intestinal absorption of sorbitol: role of gastric emptying

The aim of our study was to test the hypothesis that the better absorption of sorbitol when ingested with glucose could be related to a delayed gastric emptying. We tested the effect of the ingestion of glucose and lipids on the gastric emptying and intestinal absorption of sorbitol in six healthy volunteers, using gastric scintigraphy and hydrogen breath test. After an overnight fast, subjects ingested in random order, on 48-h test periods separated by at least one week, the following solutions: (a) 20 g sorbitol alone; (b) 20 g sorbitol and 20 g glucose; (c) 20 g sorbitol and 9 g lipids. Isotopic acquisitions were taken for 3 h following the ingestion of sorbitol labelled with 111Indium. Hydrogen concentration was measured in end-expiratory samples during 5 h, and the areas under the breath hydrogen curve, reflecting the amounts of sorbitol unabsorbed in the small bowel, were compared between periods. Mean area under the curve was 397 +/- 159 when sorbitol was ingested alone, and this was significantly lower when ingested with glucose or lipids (313 +/- 181 and 337 +/- 135, respectively; P < 0.05). The three curves of sorbitol gastric emptying differed significantly from each other, the gastric emptying being the slowest for sorbitol plus lipids, and the fastest for sorbitol taken alone. We found a positive correlation between the half-emptying time and the hydrogen areas under the curve (r = 0.46, P = 0.05). In conclusion, our study demonstrates that adding glucose or lipids to a solution of sorbitol slows the gastric emptying of sorbitol, resulting in a better intestinal absorption of sorbitol.

Sorbitol malabsorption and nonspecific abdominal symptoms in type II diabetes

Some data suggest that sorbitol intake may be responsible for diarrhea in diabetic patients. One hundred thirteen hydrogen breath tests were performed in type II diabetics (72) and normal controls (41) after oral loads of sorbitol ranging from 2.5 to 20 g in iso-osmolar solutions to assess the role of malabsorption of this compound in the genesis of abdominal symptoms. The prevalence of sorbitol malabsorption and abdominal symptoms, peak (Cmax H2) and total (Ctot H2) hydrogen production, and mouth to cecum transit time (MCTT) did not differ in type II diabetics and controls. Malabsorption was observed more frequently with the highest doses of sorbitol (10% of patients at a dose of 2.5 g and approximately 75% at 20 g). Symptoms, usually consisting of mild discomfort and abdominal distension, were observed only after sorbitol loads of 10 and 20 g in 27.2% of the diabetics and in 36.3% of the controls. Diarrhea was present in three subjects (two diabetics and one control) only at a dose of 20 g. These data indicate that it is highly unlikely for sorbitol to play a role in inducing diabetes diarrhea. A moderate (up to 10 g) sorbitol intake is not contraindicated in type II diabetics.

Gastrointestinal transit and digestibility of maltitol, sucrose and sorbitol in rats: a multicompartmental model and recovery study

Using data obtained with a dye marker and the gavage technique, the kinetics of gastrointestinal transit of different loads of sugar substitutes (maltitol, sorbitol) and sugar (sucrose) in the rat were analysed using a linear multicompartmental model over a range from the realistic to the non-physiologic high, of carbohydrate intake levels and using only a few experimental time points. The model gave detailed insight into intestinal propulsion and gastrocecal transit time. Rate constants of transport between the compartments investigated were determined; they showed characteristics which could be related to the substance and the dosage administered. Analyses of the gastrointestinal content and calculations of the intestinal net water movement showed that the digestibility and absorption of the disaccharide sugar alcohol, maltitol, in the small gut depended inversely on the dose ingested. For all substances tested, caloric availability in the small intestine was calculated. At a physiological low level of maltitol intake, the results also indicated an insignificant calorie-saving effect in comparison to sucrose, an effect based mainly on the slow absorption rate of the maltitol cleavage product sorbitol.