13-Week oral toxicity study with isomaltulose (Palatinose) in rats

Impact of artificial sweeteners and rare sugars on the gut microbiome

Alternative sugars are often used as sugar substitutes because of their low calories and glycemic index. Recently, consumption of these sweeteners in diet foods and beverages has increased dramatically, raising concerns about their health effects. This review examines the types and characteristics of artificial sweeteners and rare sugars and analyzes their impact on the gut microbiome. In the section on artificial sweeteners, we have described the chemical structures of different sweeteners, their digestion and absorption processes, and their effects on the gut microbiota. We have also discussed the biochemical properties and production methods of rare sugars and their positive and negative effects on gut microbial communities. Finally, we have described how artificial sweeteners and rare sugars alter the gut microbiome and how these changes affect the gut environment. Our observations aim to improve our understanding regarding the potential health implications of the consumption of artificial sweeteners and low-calorie sugars.

Safety of isomaltulose syrup (dried) as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on isomaltulose syrup (dried) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF consists of a mixture of mono- and disaccharides in powder form, mainly composed of isomaltulose (≥ 75%) and trehalulose (< 13%). The applicant intends to use the NF as a replacement for sucrose already on the market. The information provided on the manufacturing process, composition and specifications of the NF is sufficient and does not raise safety concerns. No absorption, distribution, metabolism and excretion (ADME) or toxicological data were provided for the NF. Instead, the safety of the NF was assessed based on literature data available on isomaltulose and mixtures of isomaltulose and trehalulose. In addition, considering the nature, compositional characterisation and production process of the NF, the Panel considered that such data were sufficient to conclude that the NF is as safe as sucrose.

Effects of Natural Alternative Sweeteners on Metabolic Diseases

The rising prevalence of obesity and diabetes is a significant health concern both in globally and is now regarded as a worldwide epidemic. Added sugars like sucrose and high-fructose corn syrup (HFCS) are a major concern due to their link with an increased incidence of diet-induced obesity and diabetes. The purpose of this review is to provide insight into the effects of natural sweeteners as alternatives to sucrose and HFCS, which are known to have negative impacts on metabolic diseases and to promote further research on sugar consumption with a focus on improving metabolic health. The collective evidences suggest that natural alternative sweeteners have positive impacts on various markers associated with obesity and diabetes, including body weight gain, hepatic fat accumulation, abnormal blood glucose or lipid homeostasis, and insulin resistance. Taken together, natural alternative sweeteners can be useful substitutes to decrease the risk of obesity and diabetes compared with sucrose and HFCS.

Conditioned preference and avoidance induced in mice by the rare sugars isomaltulose and allulose

Isomaltulose, a slowly digested isocaloric analog of sucrose, and allulose, a noncaloric fructose analog, are promoted as "healthful" sugar alternatives in human food products. Here we investigated the appetite and preference conditioning actions of these sugar analogs in inbred mouse strains. In brief-access lick tests (Experiment 1), C57BL/6 (B6) mice showed similar concentration dependent increases in licking for allulose and fructose, but less pronounced concentration-dependent increases in licking for isomaltulose than sucrose. In Experiment 2, B6 male were given one-bottle training with a CS+ flavor (e.g., grape) mixed with 8% isomaltulose or allulose and a CS- flavor (e.g., cherry) mixed in water followed by two-bottle CS flavor tests. The isomaltulose mice showed only a weak CS+ flavor preference but a strong preference for the sugar over water. The allulose mice strongly preferred the CS- flavor and water over the sugar. The allulose avoidance may be due to gut discomfort as reported in humans consuming high amounts of the sugar. Experiment 3 found that the preference for 8% sucrose over 8% isomaltulose could be reversed or blocked by adding different concentrations of a noncaloric sweetener mixture (sucralose + saccharin, SS) to the isomaltulose. Experiment 4 revealed that the preference of B6 or FVB/N mice for isomaltulose+0.01%SS or sucrose over 0.1%SS increased after separate experience with the sugars and SS. This indicates that isomaltulose, like sucrose, has postoral appetition effects that enhances the appetite for the sugar. In Experiments 5 and 6, the appetition actions of the two sugars were directly compared by giving mice isomaltulose+0.05%SS vs. sucrose choice tests before and after separate experience with the two sugars. In general, the initial preference the mice displayed for isomaltulose+0.05%SS was reduced or reversed after separate experience with the two sugars although some strain and sex differences were obtained. This indicates that isomaltulose has weaker postoral appetition effects than sucrose.

Toxicological evaluation of the red mold rice extract, ANKASCIN 568-R: 13-week chronic toxicity, and genotoxicity studies

ANKASCIN 568-R is an extract derived from red mold rice (RMR) fermented using Monascus purpureus NTU 568. RMR fermented using M. purpureus NTU 568 prevents cardiovascular diseases and decreases blood lipid levels. This study evaluates the safety of ANKASCIN 568-R, since it has not determined yet. After daily oral ANKASCIN 568-R for 13 consecutive weeks, we evaluated the toxicity tolerance of Sprague-Dawley rats and performed dose formulation analysis on monascin and ankaflavin. The dose formulation analysis showed that ANKASCIN 568-R concentrations were lower than the target concentration and out of range ( ± 15%) at week 8 and on the last dosing day for both monascin (all dose groups) and ankaflavin at the 100 mg/kg dose. The lowest reported concentrations for the low, middle, and high dose formulations were 34.7, 115.2, and 398.1 mg/mL, respectively. We also evaluated the genotoxicity of ANKASCIN 568-R and showed no genotoxicity potential at all ANKASCIN 568-R doses investigated. The no observed adverse effect level of ANKASCIN 568-R was determined to be 796.2 mg/kg/day. This study revealed the first toxicity evaluation data of ANKASICN 568-R, and the data demonstrated ANKASICN 568-R was safe and can be used in daily life.

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The non-observed-adverse-effect level for ANKASCIN 568-R was 796.2 mg/kg/day.

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ANKASCIN 568-R showed no toxic effects in the 13-week oral toxicity study.

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No genotoxicity markers were observed at all ANKASCIN 568-R doses tested.

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ANKASCIN 568-R did not induce chromosomal aberration in CHO cells.

A head-to-head comparison review of biological and toxicological studies of isomaltulose, d-tagatose, and trehalose on glycemic control

Diabetes mellitus is the most common metabolic disorder contributing to significant morbidity and mortality in humans. Different preventive and therapeutic agents, as well as various pharmacological strategies or non-pharmacological tools, improve the glycemic profile of diabetic patients. Isomaltulose, d-tagatose, and trehalose are naturally occurring, low glycemic sugars that are not synthesized by humans but widely used in food industries. Various studies have shown that these carbohydrates can regulate glucose metabolism and provide support in maintaining glucose homeostasis in patients with diabetes, but also can improve insulin response, subsequently leading to better control of hyperglycemia. In this review, we discussed the anti-hyperglycemic effects of isomaltulose, D-tagatose, and trehalose, comparing their properties with other known sweeteners, and highlighting their importance for the development of the pharmaceutical and food industries.

Stem vacuole-targetted sucrose isomerase enhances sugar content in sorghum

BACKGROUND

Sugar content is critically important in determining sugar crop productivity. However, improvement in sugar content has been stagnant among sugar crops for decades. Sorghum, especially sweet sorghum with high biomass, shown great potential for biofuel, has lower sugar content than sugarcane. To enhance sugar content, the sucrose isomerase (SI) gene, driven by stem-specific promoters (A2 or LSG) with a vacuole-targetted signal peptide, was transformed into the sorghum inbred line (T×430).

RESULTS

The study demonstrated that transgenic lines of grain sorghum, containing 50-60% isomaltulose, accumulated up to eightfold (1000 mM) more total sugar than the control T×430 did (118 mM) in stalks of T₀ generation. Subsequently, the elite engineered lines (A5, and LSG9) were crossed with sweet sorghum (Rio, and R9188). Total sugar contents (over 750 mM), were notably higher in F₁, and F₂ progenies than the control Rio (480 mM). The sugar contents of the engineered lines (over 750 mM), including T₀, T₁, F₁, and F₂, are surprisingly higher than that of the field-grown sugarcane (normal range 600-700 mmol/L). Additionally, analysis of physiological characterization demonstrated that the superior progenies had notably higher rates of photosynthesis, sucrose transportation, and sink strength than the controls.

CONCLUSIONS

The genetic engineering approach has dramatically enhanced total sugar content in grain sorghum (T₀, and T₁) and hybrid sorghum (F₁, and F₂), demonstrating that sorghum can accumulate as high or higher sugar content than sugarcane. This research illustrates that the SI gene has enormous potential on improvement of sugar content in sorghum, particularly in hybirds and sweet sorghum. The substantial increase on sugar content would lead to significant financial benefits for industrial utilization. This study could have a substantial impact on renewable bioenergy. More importantly, our results demonstrated that the phenotype of high sugar content is inheritable and shed light on improvement for other sugar crops.

Leucrose, a Sucrose Isomer, Suppresses Hepatic Fat Accumulation by Regulating Hepatic Lipogenesis and Fat Oxidation in High-fat Diet-induced Obese Mice

Obesity is currently one of the most serious public health problems and it can lead to numerous metabolic diseases. Leucrose, d-glucopyranosyl-α-(1-5)-d-fructopyranose, is an isoform of sucrose and it is naturally found in pollen and honey. The aim of this study was to investigate the effect of leucrose on metabolic changes induced by a high-fat diet (HFD) that lead to obesity. C57BL/6 mice were fed a 60% HFD or a HFD with 25% (L25) or 50% (L50) of its total sucrose content replaced with leucrose for 12 weeks. Leucrose supplementation improved fasting blood glucose levels and hepatic triglyceride content. In addition, leucrose supplementation reduced mRNA levels of lipogenesis-related genes, including peroxisome proliferator-activated receptor γ, sterol regulatory element binding protein 1C, and fatty acid synthase in HFD mice. Conversely, mRNA levels of β oxidation-related genes, such as carnitine palmitoyltransferase 1A and acyl CoA oxidase, returned to control levels with leucrose supplementation. Taken together, these results demonstrated the therapeutic potential of leucrose to prevent metabolic abnormalities by mediating regulation of plasma glucose level and hepatic triglyceride accumulation.

Acute and 13-week subchronic toxicological evaluations of turanose in mice

BACKGROUND/OBJECTIVES

Turanose, α-D-glucosyl-(1→3)-α-D-fructose, is a sucrose isomer which naturally exists in honey. To evaluate toxicity of turanose, acute and subchronic oral toxicity studies were conducted with ICR mice.

MATERIALS AND METHODS

For the acute oral toxicity study, turanose was administered as a single oral dose [10 g/kg body weight (b.w.)]. In the subchronic toxicity study, ICR mice were administered 0, 1.75, 3.5, and 7 g/kg b.w. doses of turanose daily for 13 weeks.

RESULTS

No signs of acute toxicity, including abnormal behavior, adverse effect, or mortality, were observed over the 14-day study period. In addition, no changes in body weight or food consumption were observed and the median lethal dose (LD₅₀) for oral intake of turanose was determined to be greater than 10 g/kg b.w. General clinical behavior, changes in body weight and food consumption, absolute and relative organ weights, and mortality were not affected in any of the treatment group for 13 weeks. These doses also did not affect the macroscopic pathology, histology, hematology, and blood biochemical analysis of the mice examined.

CONCLUSION

No toxicity was observed in the acute and 13-week subchronic oral toxicology studies that were conducted with ICR mice. Furthermore, the no-observed-adverse-effect level is greater than 7 g/kg/day for both male and female ICR mice.

Novel findings on the metabolic effects of the low glycaemic carbohydrate isomaltulose (Palatinose)

The slow digestible disaccharide isomaltulose (iso; Palatinose) is available as novel functional carbohydrate ingredient for manufacturing of low glycaemic foods and beverages. Although basically characterised, various information on physiological effects of iso are still lacking. Thus, the objective of the present study was to expand scientific knowledge of physiological characteristics of iso by a set of three human intervention trials. Using an ileostomy model, iso was found to be essentially absorbed, irrespective of the nature of food (beverage and solid food). Apparent digestibility of 50 g iso from two different meals was 95.5 and 98.8 %; apparent absorption was 93.6 and 96.1 %, respectively. In healthy volunteers, a single dose intake of iso resulted in lower postprandial blood glucose and insulin responses than did sucrose (suc), while showing prolonged blood glucose delivery over 3 h test. In a 4-week trial with hyperlipidaemic individuals, regular consumption of 50 g/d iso within a Western-type diet was well tolerated and did not affect blood lipids. Fasting blood glucose and insulin resistance were lower after the 4-week iso intervention compared with baseline. This would be consistent with possible beneficial metabolic effects as a consequence of the lower and prolonged glycaemic response and lower insulinaemic burden. However, there was no significant difference at 4 weeks after iso compared with suc. In conclusion, the study shows that iso is completely available from the small intestine, irrespective of food matrix, leading to a prolonged delivery of blood glucose. Regular iso consumption is well tolerated also in subjects with increased risk for vascular diseases.

Effects of a Novel Palatinose Based Enteral Formula (MHN-01) Carbohydrate-Adjusted Fluid Diet in Improving the Metabolism of Carbohydrates and Lipids in Patients with Esophageal Cancer Complicated by Diabetes Mellitus

BACKGROUND

During perioperative management of patients with gastrointestinal cancer complicated by diabetes mellitus, adequate alimentation is required, but we often face difficulties associated with hyperglycemia and other accompanying complications. Recently, we investigated the effects of a novel palatinose based enteral formula (MHN-01) in suppressing post-prandial hyperglycemia and improving lipid metabolism in experimental animals and perioperative management of patients with esophageal cancer complicated by diabetes mellitus.

MATERIALS AND METHODS

We gave normal rats and rats with type 2 diabetes mellitus a single oral dose of fluid diet, and analyzed comparatively the time course of blood glucose level in each group until 3 h after the dose. In both the normal rat group and the type 2 diabetes group, peak blood glucose level after the MHN-01 dose was significantly lower than after a dose of ordinary fluid diet and was comparable to the peak level after a dose of a fluid diet rich in MUFA (monounsaturated fatty acid). We allowed normal mice free access to fluid diet for 43 days, and measured their body fat levels. Fat accumulation was significantly lower in mice given MHN-01 than in mice given ordinary fluid diet. We also analyzed the respiratory quotient and resting energy expenditure of normal Sprague-Dawley rats fed by MHN-01 or an ordinary fluid diet. The respiratory quotient of the MHN-01 group was significantly lower than the ordinary fluid group, although the resting energy expenditure of both groups was almost the same level. The effect of MHN-01 was estimated to be based on improvement of lipid metabolism.

RESULTS

Between 2003 and 2005, among 164 patients who underwent radical thoracic esophagectomy and/or reconstruction for esophageal carcinoma at Okayama University Hospital, nine patients (5.5%) were diagnosed with diabetes mellitus in pre-operative screening and were treated with MHN-01. Clinical courses of two cases with severe status of diabetes mellitus were presented as successful case reports of MHN-01.

CONCLUSION

MHN-01 was very useful in perioperative management of patients complicated by diabetes mellitus, unable to ingest food p.o. such as esophageal cancer or other diseases.

Isomaltulose (Palatinose): a review of biological and toxicological studies

Isomaltulose is a natural occurring disaccharide composed of alpha-1,6-linked glucose and fructose. Commercial isomaltulose is produced from sucrose by enzymatic rearrangement and has been used as a sugar in Japan since 1985. It is particularly suitable as a non-cariogenic sucrose replacement and is favorable in products for diabetics and prediabetic dispositions. In vivo studies with rats and pigs indicate that isomaltulose is completely hydrolyzed and absorbed in the small intestine. This is supported by in vitro studies showing that intestinal disaccharidases from various species (including man) can hydrolyze isomaltulose. The rate of hydrolysis, however, is very slow compared with sucrose and maltose. Thus, blood glucose and insulin levels in humans after oral administration rise slower and reach lower maxima than after sucrose administration. After absorption, fructose and glucose are metabolized as typical for these monosaccharides. From intravenous studies it can be assumed that any systemic isomaltulose would be hydrolyzed as well, or excreted in urine. In several subchronic toxicity studies, the administration of large doses (up to 7.0 and 8.1 g/kg body weight/day in male and female rats, respectively) of isomaltulose, did not result in adverse effects. Isomaltulose induced neither embryotoxic or teratogenic effects in rat foetuses, nor maternal toxicity at levels up to 7 g/kg body weight/day. Isomaltulose was non-mutagenic in the Ames test. As hydrolysis in the small intestine is complete, even high levels of isomaltulose are well tolerated in animals and humans. In studies with healthy as well as diabetic subjects high doses up to 50 g were tolerated without signs of intestinal discomfort. On the basis of the data reviewed it is concluded that the use of isomaltulose as an alternative sugar is as safe as the use of other digestible sugars consisting of glucose and fructose.