Resistant Maltodextrin Suppresses Intestinal Phenols Production by Modifying the Intestinal Environment.

Protein is an essential nutrient that plays several roles in the maintenance of the human body. A high-protein diet is also known to play an important role in weight management in obese individuals and in maintaining muscle strength in the elderly. However, over-consumption of protein can have negative effects on health, including deterioration of the intestinal environment by the production of amino acid metabolites such as phenols. Interest in the regulation of the intestinal environment to maintain health has gained attention recently. Resistant maltodextrin (RMD) is a prebiotic dietary fiber. Therefore, we investigated whether RMD suppressed the production of amino acid metabolites through intestinal regulation in rats. Wistar rats were fed either an AIN-93G diet or a modified AIN-93G diet containing 5% tyrosine. RMD (2.5% or 5.0%) was provided with drinking water. The rats were fed these diets and water ad libitum for 3 wk. Urine was collected overnight, after which serum, liver, kidneys, and the whole cecum were collected from rats under anesthesia with isoflurane for analysis of phenols and microbiota. RMD decreased the cecal, serum, and urinary levels of phenols, especially phenol. Moreover, the relative abundance of intestinal Romboutsia ilealis showed a significant correlation with the cecal phenols levels, and RMD decreased the abundance of this species. Thus, RMD may suppress phenols production and decrease serum phenols levels by altering the intestinal environment in rats.

Safety evaluation and maximum use level for transient ingestion in humans of allitol.

Allitol is a hexitol produced by reducing the rare sugar D-allulose with a metal catalyst under hydrogen gas. To confirm the safe level of allitol, we conducted a series of safety assessments. From the results of Ames mutagenicity assay using Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537, Escherichia coli strain WP2uvrA, and an in vitro chromosomal aberration test on cultured Chinese hamster cells, allitol did not show any significant genotoxic effect. No significant effects on general condition, urinalysis, hematology, physiology, histopathology, or at necropsy were observed at a dose of 1500 mg/kg body weight of allitol in the acute and 90-day subchronic oral-toxicity assessments for rats. A further study performed on healthy adult humans showed that the acute use level of allitol for diarrhea was 0.2 g/kg body weight for both men and women. The results of current safety assessment studies suggest that allitol is safe for human consumption.

Is Fibersol-2 efficacious in reducing duration of watery diarrhea and stool output in children 1-3 years old? A randomized, parallel, double-blinded, placebo-controlled, two arm clinical trial.

BACKGROUND: Fibersol-2 has innumerable beneficial effects on human health. It is a fermentable, non-viscous, water-soluble, indigestible dextrin containing 90% dietary fiber produced from corn starch. We aimed to evaluate whether additional intake of Fibersol-2 along with oral rehydration solution treatment can reduce the duration of watery diarrhea and daily stool output in children 1-3 years as well as recovery of such children within 72 hours, compared to placebo. METHODS: This placebo-controlled double-blinded, randomized parallel two arm trial conducted in Kumudini Women's Medical College Hospital in rural Bangladesh between March and October, 2018 used 5 gm of either Fibersol-2 or placebo dissolved in 50-ml drinking water which was given orally to ninety-two children with watery diarrhea on enrollment twice daily for a period of 7 days. Randomization was done using a randomization table. We randomly allocated 45 (49%) and 47 (51%) children in Fibersol-2 and placebo groups, respectively. Outcome measures were duration of resolution of watery diarrhea, daily stool output and the proportion of children recovered within 72 hours. Primary and safety analyses were by intention to treat. This trial was registered at ClinicalTrials.gov, number NCT03565393. RESULTS: There was no significant difference observed in terms of duration of resolution of diarrhea (adjusted mean difference 8.20, 95% CI -2.74 to 19.15, p = 0.14, adjusted effect size 0.03); the daily stool output (adjusted mean difference 73.57, 95% CI -94.17 to 241.32, p = 0.38, adjusted effect size 0.33) and the proportion of children recovered within 72 hours (adjusted odds ratio 0.49, 95% CI = 0.12 to 1.96, p = 0.31, adjusted risk difference -0.06 (95% CI -0.19 to -0.06), after regression analysis between Fibersol-2 and placebo. CONCLUSION: No beneficial role of Fibersol-2 was observed in diarrheal children aged 1-3 years. TRIAL REGISTRATION: This trial is registered at ClinicalTrials.gov, number NCT03565393. The authors confirmed that all ongoing and related trials for this drug/intervention are registered. https://clinicaltrials.gov/ct2/show/NCT03565393.

Digestive tolerability and acceptability of Fibersol-2 in healthy and diarrheal children 1-3 years old at a rural facility, Bangladesh: Results from a four arm exploratory study.

BACKGROUND: Fibersol-2 has some beneficial effects on human health. We aimed to evaluate the digestive tolerability and acceptability of Fibersol-2 in healthy and diarrheal children, as well as improvement in stool consistencies in young diarrheal children. METHODS: Sixty children of either sex, aged 1-3 years having four groups (healthy children/low dose, healthy children/high dose, children with diarrhea/low dose and children with diarrhea/high dose) were enrolled into this exploratory study between 1st August to 23rd October 2017. Two presumptive doses, low (2.5g) and high (5g), twice daily with 50 ml drinking water for seven days were the interventions. Outcomes were to observe the development of possible abdominal symptoms, such as pain, distension, rumbling, and bloating during the intervention and post-intervention periods in healthy and diarrheal children as well as improvement in stool consistencies in diarrheal children. RESULTS: Among the diarrheal children, the median (IQR) duration of resolution of diarrhea was 3.9 (2.9, 5.1) days vs. 3.5 (2.0, 8.0) days, p = 0.885; in low dose and high dose groups, respectively. Significant difference was observed in terms of abdominal pain (27% vs. 7%, p = 0.038) and distension (40% vs. 0%, p<0.001) in diarrheal children, compared to healthy children during the pre-intervention period. We also observed significant difference in respect of abdominal distension (23% vs. 0%, p = 0.011), rumbling (27% vs. 0%, p = 0.005) and bloating (43% vs. 3%, p = 0.001) in diarrheal children, compared to healthy children during the intervention period. However, no significant difference was observed in relation to abdominal pain (p = 0.347) and distension (p = 0.165) during the pre-intervention period, compared to the intervention period in diarrheal children. Moreover, no significant difference was observed during the post-intervention period for the diarrheal and healthy children. CONCLUSION: Fibersol-2 was found to be well tolerated in healthy and diarrheal children aged 1-3 years. TRIAL REGISTRATION: This study was registered as part of a randomized trial at ClinicalTrials.gov, number NCT03565393. The authors confirmed that all ongoing and related trials for this drug/intervention were registered.

Resistant Maltodextrin Intake Reduces Virulent Metabolites in the Gut Environment: A Randomized Control Study in a Japanese Cohort.

In recent years, there have been many reports on the effects of prebiotics on intestinal health. In particular, the consumption of resistant maltodextrin (RMD) has been reported to be beneficial. However, there has been no comprehensive quantification of the effect of RMD on the intestinal environment. Therefore, this study aimed to quantify the effects of RMD on the intestine, especially the intestinal microbiome and metabolome profiles. A randomized, double-blind, and controlled trial was conducted in 29 Japanese subjects, whose hemoglobin A1c (HbA1c) levels are larger than 6% (Clinical trial no. UMIN000023970, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000027589). The subjects consumed RMD or placebo twice per day for 24 weeks. Blood and fecal samples were collected before and after the intake. The intestinal environment was assessed by a metabologenomics approach, involving 16S rRNA gene-based microbiome analysis and mass spectrometry-based metabolome analysis. The intake of RMD increased the levels of Bifidobacterium and Fusicatenibacter and decreased deoxycholate levels. Additionally, intake of RMD lowered the levels of some opportunistic virulent metabolites, such as imidazole propionate and trimethylamine, in subjects with an initially high amount of those metabolites. RMD may have beneficial effects on the gut environment, such as commensal microbiota modulation and reduction of virulence metabolites, which is known as a causative factor in metabolic disorders. However, the effects of RMD partially depend on the gut environmental baseline.

Visceral Fat-Reducing Effect and Safety of Continuous Consumption of Beverage Containing Resistant Maltodextrin: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Clinical Trial.

Obesity is regarded as a global concern with increasing prevalence, most notably in developed countries. Metabolic syndrome is a predictor of cardiovascular disease and type 2 diabetes mellitus and is defined as the accumulation of multiple risk factors caused by abdominal visceral obesity. Resistant maltodextrin (RMD) is a soluble dietary fiber that has been shown to reduce visceral fat in long-term clinical trials when continuously administered at 10 g, three times daily. Herein, we evaluated the effects of long-term consumption of 5 g RMD three times daily. A total of 140 healthy adults were randomly assigned to two intervention groups for a 12-wk randomized, double-blind, placebo-controlled, parallel-group trial. Participants ingested a test beverage containing 5 g RMD or a placebo beverage without RMD. Interviews, anthropometric measurements, physiological examination, blood tests, and urinalyses were conducted at baseline and every 4 wk during the trial. Computed tomography scans were performed at baseline and at the end of week 8 and 12. Results showed that abdominal visceral fat area (VFA) significantly decreased in the test group from 105.33±26.83 cm2 at baseline to 101.15±24.33 cm2 at week 12. Further, a significant difference was observed in the VFA between the test and control groups (p<0.05), confirming the function of continuous RMD consumption in reducing abdominal visceral fat. Furthermore, neither serious adverse events nor adverse clinical findings were observed in the blood or urine tests following consumption of RMD, suggesting that continuous consumption of RMD containing beverages is safe.

Analysis of 2-aminopyridine labeled glycans by dual-mode online solid phase extraction for hydrophilic interaction and reversed-phase liquid chromatography.

Quantitative analysis of glycans released from glycoproteins using high-performance liquid chromatography (HPLC) requires fluorescent tag labeling to enhance sensitivity and selectivity. However, the methods required to remove large amounts of excess labeling reagents from the reaction mixture are time-consuming. Furthermore, these methods, including solvent extraction and solid phase extraction (SPE), often impair quantitative analysis. Here, we developed an online sample cleanup procedure for HPLC analysis of 2-aminopyridine (AP)-labeled glycans using a six-port/two-way valve and two small columns: one packed with a strong cation exchange resin (SCX) and the other comprising ODS silica gel. AP-labeled glycans delivered from an injection port were separated from excess AP by passing through an SCX column (4.6 mm i.d., 1 cm long) regulated to 40°C. The AP-labeled glycans were trapped on an ODS column (4.6 mm i.d., 1 cm long) to further separate them from inorganic contaminants. By changing the valve position after 2 min to connect the ODS column to an analysis column, AP-labeled glycans trapped in the ODS column were eluted with an acetonitrile-containing eluent followed by hydrophilic interaction liquid chromatography (HILIC) separation on an amide column or reversed-phase mode separation on a C30 column. This method was successfully used to analyze N-linked glycans released from several glycoprotein samples.

Suppressive effect of dietary resistant maltodextrin on systemic immunity in a mouse model of food allergy.

Resistant maltodextrin (RMD) is a soluble dietary fibre that exerts several physiological functions as a result of its microbial degradation and changes in the intestinal environment. It has been reported that RMD enhanced immunoglobulin A (IgA) secretion, which protects the mucosa from foreign substances. However, the effect of RMD on excessive immunity has yet to be investigated. In this study, we aimed to investigate the effect of RMD on excessive immune responses such as food allergy. OVA23-3 mice were fed an AIN-76-based diet containing 20% egg-white protein with or without RMD. While RMD was shown to contribute to an increase in goblet cells, RMD did not change the overall inflammatory status when ingested with the egg-white diet. RMD suppressed IL-4 and IL-10 production from splenocytes but not cells from mesenteric lymph nodes. RMD also downregulated the serum levels of OVA-specific Th1- and Th2-related antibodies, which were elevated in the food-allergic condition. RMD significantly increased the total amount of short-chain fatty acids, especially acetate and propionate, in the caecum of OVA23-3 mice fed the egg-white diet. Our study demonstrated that dietary RMD modulates systemic rather than intestinal antigen-specific immune responses in the food-allergic condition of OVA23-3 mice. Although the relevant mechanism has yet to be investigated, RMD shows potential for alleviating food allergy through adjustment of systemic immunity.

Tandem Cation/Anion Exchange SPE Cartridge Method for Sample Desalting for HPLC Analysis of Soluble Dietary Fiber: Development and Inter-laboratory Validation.

In HPLC analyses of soluble dietary fiber, desalting processes using open, mixed-bed ion-exchange columns are time-consuming and labor-intensive. We developed and validated a simple desalting method using tandem cation/anion exchange SPE cartridges. We found that combining Bond Elut Jr SCX (upstream) and Bond Elut PSA (downstream) cartridges provided adequate desalting of test solutions. The developed method was then validated in an inter-laboratory study. Five test samples were prepared by mixing food matrixes with purified soluble dietary fiber and treated to generate solutions to test the desalting process. These solutions were then analyzed by eight different laboratories. The results demonstrated that the developed method is simple and reliable for desalting samples containing 140 to 945 mg/100 mL of soluble dietary fiber in preparation for HPLC analysis of soluble dietary fiber.

Secretion of GLP-1 but not GIP is potently stimulated by luminal d-Allulose (d-Psicose) in rats.

Glucagon-like peptide 1 (GLP-1), an incretin gastrointestinal hormone, is secreted when stimulated by nutrients including metabolizable sugars such as glucose and fructose. d-Allulose (allulose), also known as d-psicose, is a C-3 isomer of d-fructose and a rare sugar with anti-diabetic or anti-obese effects in animal models. In the present study, we examined whether an oral administration of allulose could stimulate GLP-1 secretion in rats, and investigated the underlying mechanisms. Oral, but not intraperitoneal, administration of allulose (0.5-2.0 g/kg body weight) elevated plasma GLP-1 levels for more than 2 h in a dose-dependent manner. The effects of allulose on GLP-1 secretion were higher than that of dextrin, fructose, or glucose. In addition, oral allulose increased total and active GLP-1, but not glucose-dependent insulinotropic polypeptide (GIP), levels in the portal vein. In anesthetized rats equipped with a portal catheter, luminal (duodenum and ileum) administration of allulose increased portal GLP-1 levels, indicating the luminal effect of allulose. Allulose-induced GLP-1 secretion was abolished in the presence of xanthohumol (a glucose/fructose transport inhibitor), but not in the presence of inhibitors of the sodium-dependent glucose cotransporter 1 or the sweet taste receptor. These results demonstrate a potent and lasting effect of orally administered allulose on GLP-1 secretion in rats, without affecting GIP secretion. The potent and selective GLP-1-releasing effect of allulose holds promise for the prevention and treatment of glucose intolerance through promoting endogenous GLP-1 secretion.

Resistant maltodextrin or fructooligosaccharides promotes GLP-1 production in male rats fed a high-fat and high-sucrose diet, and partially reduces energy intake and adiposity.

PURPOSE: Increasing secretion and production of glucagon-like peptide-1 (GLP-1) by continuous ingestion of certain food components has been expected to prevent glucose intolerance and obesity. In this study, we examined whether a physiological dose (5% weight in diet) of digestion-resistant maltodextrin (RMD) has a GLP-1-promoting effect in rats fed a high-fat and high-sucrose (HFS) diet. METHODS: Rats were fed a control diet or the HFS (30% fat, 40% sucrose wt/wt) diet supplemented with 5% RMD or fructooligosaccharides (FOS) for 8 weeks or for 8 days in separated experiments. Glucose tolerance, energy intake, plasma and tissue GLP-1 concentrations, and cecal short-chain fatty acids concentrations were assessed. RESULTS: After 4 weeks of feeding, HFS-fed rats had significantly higher glycemic response to oral glucose than control rats, but rats fed HFS + RMD/FOS did not (approx. 50% reduction vs HFS rats). HFS + RMD/FOS-fed rats had higher GLP-1 responses (~twofold) to oral glucose, than control rats. After 8 weeks, visceral adipose tissue weight was significantly higher in HFS-fed rats than control rats, while HFS + RMD/FOS rats had a trend of reduced gain (~50%) of the tissue weight. GLP-1 contents and luminal propionate concentrations in the large intestine increased (>twofold) by adding RMD/FOS to HFS. Eight days feeding of RMD/FOS-supplemented diets reduced energy intake (~10%) and enhanced cecal GLP-1 production (~twofold), compared to HFS diet. CONCLUSIONS: The physiological dose of a prebiotic fiber promptly (within 8 days) promotes GLP-1 production in rats fed an obesogenic diet, which would help to prevent excess energy intake and fat accumulation.

Immunodeficiency in Two Female Patients with Incontinentia Pigmenti with Heterozygous NEMO Mutation Diagnosed by LPS Unresponsiveness.

PURPOSE: Anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID) is caused by mutations in the NF-κB essential modulator (NEMO) or NF-κB inhibitor, alpha (IKBA) genes. A heterozygous NEMO mutation causes incontinentia pigmenti (IP) in females, while a hemizygous hypomorphic mutation of NEMO causes EDA-ID in males. In general, immunodeficiency is not shown in IP patients. Here, we investigated two female patients with IP and immunodeficiency. METHODS: The patients were initially suspected to have IRAK4 deficiency and Mendelian susceptibility to mycobacterial disease, respectively, because of recurrent pneumonia with delayed umbilical cord detachment or disseminated mycobacterial infectious disease. We measured tumor necrosis factor (TNF)-α production and performed mutation screening. RESULTS: The TNF-α production from lipopolysaccharide (LPS)-stimulated CD14-positive cells was partially defective in both female patients. A genetic analysis showed them to carry the heterozygous NEMO mutations c.1167_1168insC or c.1192C>T. Although NEMO mutations in IP patients are typically eliminated by X-inactivation skewing, an analysis of cDNA obtained from the somatic cells of the patients showed the persistence of these mutations in peripheral blood mononuclear cells and peripheral granulocytes. A NF-κB reporter gene analysis using NEMO-deficient HEK293 cells showed the loss of NF-κB activity in these NEMO mutants, while the NF-κB protein expression levels by the NEMO mutants were consistent with those of wild-type NEMO. CONCLUSIONS: The delayed skewing of the mutant allele may be responsible for the observed innate immune defect in these patients. The detection of LPS unresponsiveness is suitable for identifying female IP patients with immunodeficiency.

Resistant Maltodextrin Decreases Micellar Solubility of Lipids and Diffusion of Bile Salt Micelles and Suppresses Incorporation of Micellar Fatty Acids into Caco-2 Cells.

Several studies have suggested that resistant maltodextrin (RMD) suppresses intestinal lipid absorption in experimental animals and humans. However, possible mechanisms underlying this effect are not known. In this study, effects of RMD on processes of the absorption of various lipids were investigated in vitro. RMD dose-dependently suppressed the solubility of various lipid components, including 1-mono-oleoylglycerol, oleic acid, and phosphatidylcholine in bile salt micelles in vitro. When the diffusion rate of bile salt micelles through a filter membrane was investigated in vitro, bile salt micelles containing RMD diffused more slowly than those without RMD. Incorporation of [1-14C] oleic acid into Caco-2 cells from the RMD-containing bile salt micelles was significantly smaller than that from the control micelles (without RMD). These results show that RMD suppresses intestinal absorption of lipids by decreasing their micellar solubility and the diffusion rate of bile salt micelles.

Continuous intake of resistant maltodextrin enhanced intestinal immune response through changes in the intestinal environment in mice.

We investigated the effect of resistant maltodextrin (RMD), a non-viscous soluble dietary fiber, on intestinal immune response and its mechanism in mice. Intestinal and fecal immunoglobulin A (IgA) were determined as indicators of intestinal immune response, and changes in the intestinal environment were focused to study the mechanism. BALB/c mice were fed one of three experimental diets, a control diet or a diet containing either 5% or 7.5% RMD, for two weeks. Continuous intake of RMD dose-dependently increased total IgA levels in the intestinal tract. Total IgA production from the cecal mucosa was significantly increased by RMD intake, while there were no significant differences in mucosal IgA production between the control group and experimental groups in the small intestine and colon. Continuous intake of RMD changed the composition of the cecal contents; that is, the composition of the cecal microbiota was changed, and short-chain fatty acids (SCFAs) were increased. There was an increased trend in Bacteroidales in the cecal microbiota, and butyrate, an SCFA, was significantly increased. Our study demonstrated that continuous intake of RMD enhanced the intestinal immune response by increasing the production of IgA in the intestinal tract. It suggested that the increase in total SCFAs and changes in the intestinal microbiota resulting from the fermentation of RMD orally ingested were associated with the induction of IgA production in intestinal immune cells, with the IgA production of the cecal mucosa in particular being significantly increased.

Resistant maltodextrin promotes fasting glucagon-like peptide-1 secretion and production together with glucose tolerance in rats.

Glucagon-like peptide-1 (GLP-1), which is produced and released from enteroendocrine L cells, plays pivotal roles in postprandial glycaemia. The ingestion of resistant maltodextrin (RMD), a water-soluble non-digestible saccharide, improves the glycaemic response. In the present study, we examined whether the continuous feeding of RMD to rats affected GLP-1 levels and glycaemic control. Male Sprague-Dawley rats (6 weeks of age) were fed an American Institute of Nutrition (AIN)-93G-based diet containing either cellulose (5 %) as a control, RMD (2.5 or 5 %), or fructo-oligosaccharides (FOS, 2.5 or 5 %) for 7 weeks. During the test period, an intraperitoneal glucose tolerance test (IPGTT) was performed after 6 weeks. Fasting GLP-1 levels were significantly higher in the 5 % RMD group than in the control group after 6 weeks. The IPGTT results showed that the glycaemic response was lower in the 5 % RMD group than in the control group. Lower caecal pH, higher caecal tissue and content weights were observed in the RMD and FOS groups. Proglucagon mRNA levels were increased in the caecum and colon of both RMD and FOS groups, whereas caecal GLP-1 content was increased in the 5 % RMD group. In addition, a 1 h RMD exposure induced GLP-1 secretion in an enteroendocrine L-cell model, and single oral administration of RMD increased plasma GLP-1 levels in conscious rats. The present study demonstrates that continuous ingestion of RMD increased GLP-1 secretion and production in normal rats, which could be stimulated by its direct and indirect (enhanced gut fermentation) effects on GLP-1-producing cells, and contribute to improving glucose tolerance.

The maximum single dose of resistant maltodextrin that does not cause diarrhea in humans.

The objective of the present study was to determine the maximum dose of resistant maltodextrin (Fibersol)-2, a non-viscous water-soluble dietary fiber), that does not induce transitory diarrhea. Ten healthy adult subjects (5 men and 5 women) ingested Fibersol-2 at increasing dose levels of 0.7, 0.8, 0.9, 1.0, and 1.1 g/kg body weight (bw). Each administration was separated from the previous dose by an interval of 1 wk. The highest dose level that did not cause diarrhea in any subject was regarded as the maximum non-effective level for a single dose. The results showed that no subject of either sex experienced diarrhea at dose levels of 0.7, 0.8, 0.9, or 1.0 g/kg bw. At the highest dose level of 1.1 g/kg bw, no female subject experienced diarrhea, whereas 1 male subject developed diarrhea with muddy stools 2 h after ingestion of the test substance. Consequently, the maximum non-effective level for a single dose of the resistant maltodextrin Fibersol-2 is 1.0 g/kg bw for men and >1.1 g/kg bw for women. Gastrointestinal symptoms were gurgling sounds in 4 subjects (7 events) and flatus in 5 subjects (9 events), although no association with dose level was observed. These symptoms were mild and transient and resolved without treatment.

Assessment of the safety of hydrogenated resistant maltodextrin: reverse mutation assay, acute and 90-day subchronic repeated oral toxicity in rats, and acute no-effect level for diarrhea in humans.

A series of safety assessments were performed on hydrogenated resistant maltodextrin prepared by converting the reducing terminal glucose of resistant maltodextrin into sorbitol. The reverse mutation assay did not show mutagenicity. Acute and 90-day subchronic oral toxicity studies in rats showed no death was observed in any groups, including the group receiving the highest single dose of 10 g/kg body weight or the highest dose of 5 g/kg body weight per day for 90 days. Mucous or watery stools were observed in the hydrogenated resistant maltodextrin treatment group on the acute study, which were transient and were associated with the osmotic pressure caused by intake of the high concentrations. Subchronic study showed dose-dependent increases in the weights of cecum alone, cecal contents alone, and cecum with cecal contents as well as hypertrophy of the cecal mucosal epithelium, which are considered to be common physiological responses after intake of indigestible carbohydrates. These results indicated that the no observed adverse effect level (NOAEL) of hydrogenated resistant maltodextrin was 10 g/kg body weight or more on the acute oral toxicity study and 5.0 g/kg body weight/day or more on the 90-day subchronic repeated oral toxicity study in rats. Further study performed in healthy adult humans showed that the acute no-effect level of hydrogenated resistant maltodextrin for diarrhea was 0.8 g/kg body weight for men and more than 1.0 g/kg body weight for women. The results of the current safety assessment studies suggest that hydrogenated resistant maltodextrin is safe for human consumption.

Energy value evaluation of hydrogenated resistant maltodextrin.

Hydrogenated resistant maltodextrin (H-RMD) is a dietary fiber whose energy value has not previously been reported. We evaluated the energy value of H-RMD. We conducted an in vitro digestion test, in vivo blood glucose measurement after ingestion, in vitro fermentability test, excretion test by rats and indirect calorimetry combined with breath hydrogen measurement for humans. H-RMD was hydrolyzed in vitro in a very small amount by human salivary amylase and by the rat small intestinal mucosal enzyme. Ingestion of H-RMD did not increase the blood glucose level of human subjects. An examination of in vitro fermentability suggested that H-RMD was fermented by several enterobacteria. Oral administration of H-RMD showed a saccharide excretion ratio of 42% by rats. A combination of indirect calorimetry and breath hydrogen measurement evaluated the metabolizable energy of H-RMD as 1.1 kcal/g in humans. We concluded from these results that H-RMD was not digested or absorbed in the upper gastrointestinal tract and was fermented in the colon to produce short-chain fatty acids which provided a lower amount of energy than that of resistant maltodextrin.

Improvement effect of resistant maltodextrin in humans with metabolic syndrome by continuous administration.

Resistant maltodextrin (RMD) is a soluble dietary fiber ingredient whose physiological functions are well recognized in Foods for Specified Health Use (FOSHU) for maintaining healthy intestinal regularity, blood glucose levels, and serum lipids. However, its efficacy on combined health risks--metabolic syndrome--was not studied yet. In this study the efficacy of RMD on humans with metabolic syndrome was investigated. A randomized double-blind placebo-controlled parallel-group trial was conducted. Thirty subjects with metabolic syndrome were randomly allocated into 2 groups and took either tea containing 9 g of RMD (treatment group) or placebo tea at three mealtimes daily for 12 wk. Blood was collected and body fat was scanned periodically. In the RMD treatment group, waist circumference, visceral fat area, fasting blood glucose, HOMA-R and serum triacylglycerol (TG) were significantly decreased compared to baseline, and significant time-by-treatment interaction was observed for waist circumference, visceral fat area, HOMA-R and serum TG (p=0.044, p=0.012, p=0.032, and p=0.049, respectively). The change ratio of visceral fat area showed negative statistical correlation with the baseline value (p=0.033), suggesting that efficacy of RMD was emphasized in the subjects having a larger visceral fat area. After the 12-wk RMD treatment, the total number of metabolic syndrome risk factors decreased to 20 from 32 with 2 subjects having no risks, while that of the placebo group decreased to 25 from 32. These findings suggest that continuous ingestion of RMD may improve the risk factors of metabolic syndrome by reducing visceral fat and improving glucose and lipid metabolism.

Failure of d-psicose absorbed in the small intestine to metabolize into energy and its low large intestinal fermentability in humans.

Experiments with rats have produced data on the metabolism and energy value of d-psicose; however, no such data have been obtained in humans. The authors assessed the availability of d-psicose absorbed in the small intestine by measuring carbohydrate energy expenditure (CEE) by indirect calorimetry. They measured the urinary excretion rate by quantifying d-psicose in urine for 48 hours. To examine d-psicose fermentation in the large intestine, the authors measured breath hydrogen gas and fermentability using 35 strains of intestinal bacteria. Six healthy subjects participated in the CEE test, and 14 participated in breath hydrogen gas and urine tests. d-Psicose fermentation subsequent to an 8-week adaptation period was also assessed by measuring hydrogen gas in 8 subjects. d-Psicose absorbed in the small intestine was not metabolized into energy, unlike glucose, because CEE did not increase within 3 hours of d-psicose ingestion (0.35 g/kg body weight [BW]). The accumulated d-psicose urinary excretion rates were around 70% for 0.34, 0.17, and 0.08 g/kg BW of ingested d-psicose. Low d-psicose fermentability was observed in intestinal bacteria and breath hydrogen gas tests, in which fructooligosaccharide (0.34, 0.17, and 0.08 g/kg BW) was used as a positive control because its available energy is known to be 8.4 kJ/g. Based on the results of the plot of breath hydrogen concentration vs calories ingested, the energy value of d-psicose was expected to be less than 1.6 kJ/g. Incremental d-psicose fermentability subsequent to an adaptation period was not observed.