Effect of oral D-tagatose on liver volume and hepatic glycogen accumulation in healthy male volunteers

D-Tagatose: A Rare Sugar with Functional Properties and Antimicrobial Potential against Oral Species

Carbohydrates have a dietary role, but excessive consumption of high-calorie sugars can contribute to an increased incidence of metabolic diseases and dental caries. Recently, carbohydrates with sweetening properties and low caloric value, such as D-tagatose, have been investigated as alternative sugars. D-tagatose is a rare sugar that has nutritional and functional properties of great interest for health. This literature review presents an approach to the biological effects of D-tagatose, emphasizing its benefits for oral health. Studies report that D-tagatose has antioxidant and prebiotic effects, low digestibility, reduced glycemic and insulinemic responses, and the potential to improve the lipid profile, constituting an alternative for diabetes mellitus and obesity. It can also be observed that D-tagatose has an antioxidant action, favoring the elimination of free radicals and, consequently, causing a reduction in cellular oxidative stress. Furthermore, it also has antibacterial potential against oral species. Regarding oral health, studies have shown that D-tagatose efficiently reversed bacterial coaggregations, including periodontopathogenic species, and impaired the activity and growth of cariogenic bacteria, such as S. mutans. D-tagatose significantly inhibited biofilm formation, pH decrease and insoluble glucan synthesis in S. mutans cultures. Salivary S. mutans counts were also significantly reduced by the consumption of chewing gum containing D-tagatose and xylitol. In addition, there is evidence that tagatose is effective as an air-polishing powder for biofilm decontamination. The literature indicates that D-tagatose can contribute to the prevention of systemic diseases, also constituting a promising agent to improve oral health.

Rare sugars and their health effects in humans: a systematic review and narrative synthesis of the evidence from human trials

CONTEXT

Rare sugars are monosaccharides and disaccharides (found in small quantities in nature) that have slight differences in their chemical structure compared with traditional sugars. Little is known about their unique physiological and cardiometabolic effects in humans.

OBJECTIVE

The objective of this study was to conduct a systematic review and synthesis of controlled intervention studies of rare sugars in humans, using PRISMA guidelines.

DATA SOURCES

MEDLINE and EMBASE were searched through October 1, 2020. Studies included both post-prandial (acute) and longer-term (≥1 week duration) human feeding studies that examined the effect of rare sugars (including allulose, arabinose, tagatose, trehalose, and isomaltulose) on cardiometabolic and physiological risk factors.

DATA EXTRACTION

In all, 50 studies in humans focusing on the 5 selected rare sugars were found. A narrative synthesis of the selected literature was conducted, without formal quality assessment or quantitative synthesis.

DATA SYNTHESIS

The narrative summary included the food source of each rare sugar, its effect in humans, and the possible mechanism of effect. Overall, these rare sugars were found to offer both short- and long-term benefits for glycemic control and weight loss, with effects differing between healthy individuals, overweight/obese individuals, and those with type 2 diabetes. Most studies were of small size and there was a lack of large randomized controlled trials that could confirm the beneficial effects of these rare sugars.

CONCLUSION

Rare sugars could offer an opportunity for commercialization as an alternative sweetener, especially for those who are at high cardiometabolic risk.

SYSTEMATIC REVIEW REGISTRATION

OSF registration no. 10.17605/OSF.IO/FW43D.

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.

Natural Sweeteners: The Relevance of Food Naturalness for Consumers, Food Security Aspects, Sustainability and Health Impacts

At a moment when the population is increasingly aware and involved in what it eats, both consumers and the food sector are showing more interest in natural foods. This review work discusses, addresses and provides details of the most important aspects of consumer's perceptions of and attitudes to natural foods and in-depth research into natural sweeteners. It also includes issues about their use and development as regards health impacts, food security and sustainability. In line with our main research outcome, we can assume that consumers are very keen on choosing foods with clean labelling, natural ingredients, preferably with other functional properties, without the loss of taste. In response to such a phenomenon, the food industry offers consumers alternative natural sweeteners with the advantage of added health benefits. It is noteworthy that Nature is a superb source of desirable substances, and many have a sweet taste, and many still need to be studied. Finally, we must stress that being natural does not necessarily guarantee market success.

The Effect of Small Doses of Fructose and Its Epimers on Glycemic Control: A Systematic Review and Meta-Analysis of Controlled Feeding Trials

Objective: Contrary to the concerns that fructose may have adverse metabolic effects, an emerging literature has shown that small doses (≤10 g/meal) of fructose and its low-caloric epimers (allulose, tagatose, and sorbose) decrease the glycemic response to high glycemic index meals. Whether these acute reductions manifest as sustainable improvements in glycemic control is unclear. Our objective was to synthesize the evidence from controlled feeding trials that assessed the effect of small doses of fructose and its low-caloric epimers on glycemic control. Methods: We searched MEDLINE, EMBASE, and the Cochrane Library through April 18, 2018. We included controlled feeding trials of ≥1 week that investigated the effect of small doses (≤50 g/day or ≤10% of total energy intake/day) of fructose and its low-caloric epimers on HbA_1c, fasting glucose, and fasting insulin. Two independent reviewers extracted data and assessed risk of bias. Data were pooled using the generic inverse variance method and expressed as mean differences (MDs) with 95% confidence intervals (CIs). Heterogeneity was assessed using the Cochran Q statistic and quantified using the I² statistic. Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessed the certainty of the evidence. Results: We identified 14 trial comparisons (N = 337) of the effect of fructose in individuals with and without diabetes, 3 trial comparisons (N = 138) of the effect of allulose in individuals without diabetes, 3 trial comparisons (N = 376) of the effect of tagatose mainly in individuals with type 2 diabetes, and 0 trial comparisons of the effect of sorbose. Small doses of fructose and tagatose significantly reduced HbA_1c (MD = -0.38% (95% CI: -0.64%, -0.13%); MD = -0.20% (95% CI: -0.34%, -0.06%)) and fasting glucose (MD = -0.13 mmol/L (95% CI: -0.24 mmol/L, -0.03 mmol/L)); MD = -0.30 mmol/L (95% CI: -0.57 mmol/L, -0.04 mmol/L)) without affecting fasting insulin (p > 0.05). Small doses of allulose did not have a significant effect on HbA_1c and fasting insulin (p > 0.05), while the reduction in fasting glucose was of borderline significance (p = 0.05). The certainty of the evidence of the effect of small doses of fructose and allulose on HbA_1c, fasting glucose, and fasting insulin was graded as low. The certainty of the evidence of the effect of tagatose on HbA_1c, fasting glucose, and fasting insulin was graded as moderate. Conclusions: Our results indicate that small doses of fructose and tagatose may improve glycemic control over the long term. There is a need for long-term randomized controlled trials for all four sugars to improve our certainty in the estimates.

Tagatose as a Potential Nutraceutical: Production, Properties, Biological Roles, and Applications

Nutraceuticals are gaining importance owing to their potential applications in numerous sectors including food and feed industries. Among the emerging nutraceuticals, d-tagatose occupies a significant niche because of its low calorific value, antidiabetic property and growth promoting effects on beneficial gut bacteria. As d-tagatose is present in minute quantities in naturally occurring food substances, it is produced mainly by chemical or biological means. Recently, attempts were made for bio-production of d-tagatose using l-arabinose isomerase enzyme to overcome the challenges of chemical process of production. Applications of d-tagatose for maintaining health and wellbeing are increasing due to growing consumer awareness and apprehension against modern therapeutic agents. This review outlines the current status on d-tagatose, particularly its production, properties, biological role, applications, and the future perspectives.

Recent and emerging therapeutic medications in type 2 diabetes mellitus: incretin-based, Pramlintide, Colesevelam, SGLT2 Inhibitors, Tagatose, Succinobucol

Nearly 285 million people worldwide, with 10% being Americans, suffer from diabetes mellitus and its associated comorbidities. This is projected to increase by 6.5% per year, with 439 million inflicted by year 2030. Both morbidity and mortality from diabetes stem from the consequences of microvascular and macrovascular complications. Of the 285 million with diabetes, over a quarter of a million die per year from related complications, making diabetes the fifth leading cause of death in high-income countries. These startling statistics illustrate the therapeutic failure of current diabetes drugs to retard the progression of diabetes. These statistics further illustrate the continual need for further research and development of alternative drugs with novel mechanisms to slow disease progression and disease complications. The treatment algorithm updated in 2008 by American Diabetes Association and the European Association for the Study of Diabetes currently recommends the traditional medications of metformin, either as monotherapy or in combination with sulfonylurea or insulin, as the preferred choice in the tier 1 option. The algorithm only suggests addition of alternative medications such as pioglitazone and incretin-based drugs as second-line agents in the tier 2 "less well-validated" option. However, these traditional medications have not proven to delay the progressive course of diabetes as evidence of increasing need over time for multiple drug therapy to maintain sufficient glycemic control. Because current diabetes medications have limited efficacy and untoward side effects, the development of diabetes mellitus drugs with newer mechanisms of action continues. This article will review the clinical data on the newly available incretin-based drugs on the market, including glucagon-like peptide agonists and of dipeptidyl peptidase type-4 inhibitors. It will also discuss 2 unique medications: pramlintide, which is indicated for both type and type-2 diabetes, and colesevelam, which is approved by the United States Food and Drug Administration for both type-2 diabetes and hyperlipidemia. It will further review the clinical data on the novel emerging agents of sodium-glucose cotransporter-2 inhibitors, tagatose, and succinobucol, all currently in phase III clinical trials. This review article can serve as an aid for clinicians to identify clinical indications in which these new agents can be applied in the treatment algorithm.

DDDAS Design of Drug Interventions for the Treatment of Dyslipidemia in ApoE-/- Mice

Computational models of complex systems, such as signaling networks and biological systems, can be used to explain the behavior of such systems under various conditions. The large number of integrated processes and variables, and the nonlinearities inherent in the fundamental processes, make it difficult for scientists unassisted by computer simulations to effectively predict the consequences of a particular intervention. For this reason, computer simulation has become an important tool for generating hypotheses about the behavior of these systems that can then be tested in the laboratory and clinic. A dynamic data-driven application simulation (DDDAS) was designed by Biospherics to model complex metabolic disease pathways by testing potential binary therapies in simulations at various combinations of two points in the pathways. Since DDDAS chooses the most effective pair-wise combinations, this data-driven system allows for the implementation of real-time data to model or predict a measurement or event. By incorporating data dynamically rather than statically, the predictions and measurements become more reliable. Dyslipidemia, a common precursor to atherosclerosis, can be manifested by high triglycerides, increased apolipoprotein (Apo) B, high levels of LDL, and low levels of HDL. SPX106 and D-tagatose is a combination drug therapy composed of a carbohydrate (D-tagatose) and SPX106. D-tagatose has been studied for the treatment of diabetes for several years, and has the ability to lower blood insulin levels and to decrease glycogen formation. SPX106 is a natural substance that accelerates lipid catabolism and inhibits dyslipidemia. In apolipoprotein E knockout mice (ApoE^-/-), this drug combination has been shown to significantly lower both the amount of atherosclerosis and blood cholesterol levels. This study used 26 male ApoE^-/- mice (n=13 in each group, control and treated). The control group received the normal "Western" diet (Harlan TD88137) and the treatment group received a modified version in which the sucrose was replaced with D-tagatose and 1g of SPX106 was added for every kilogram of chow. Mice were fed the diet for 8 weeks and then sacrificed via cardiac puncture. Blood serum was analyzed for cholesterol concentration. A significant difference was observed between the control and treated groups for total cholesterol levels. FPLC separations were done on fractions from both control and treated groups. A significant difference between VLDL and HDL levels was found between the treated and control mice (p<0.05 for both). Aortas were also taken and preserved in formalin to be quantified for atherosclerosis. Aortic sinuses were frozen in OCT and sectioned using a cryostat and then quantified for atherosclerosis. Treated mice showed statistically significant reduction in atherosclerosis in the aortic arch (p<0.01), the thoracic aorta (p<0.05), and the aortic sinus (p<0.05) as well as a reduction of cholesterol (p<0.05).

Fructose and galactose enhance postexercise human liver glycogen synthesis

PURPOSE

Both liver and muscle glycogen stores play a fundamental role in exercise and fatigue, but the effect of different CHO sources on liver glycogen synthesis in humans is unclear. The aim was to compare the effect of maltodextrin (MD) drinks containing galactose, fructose, or glucose on postexercise liver glycogen synthesis.

METHODS

In this double-blind, triple crossover, randomized clinical trial, 10 well-trained male cyclists performed three experimental exercise sessions separated by at least 1 wk. After performing a standard exercise protocol to exhaustion, subjects ingested one of three 15% CHO solutions, namely, FRU (MD + fructose, 2:1), GAL (MD + galactose, 2:1), or GLU (MD + glucose, 2:1), each providing 69 g CHO·h(-1) during 6.5 h of recovery. Liver glycogen changes were followed using (13)C magnetic resonance spectroscopy.

RESULTS

Liver glycogen concentration increased at faster rates with FRU (24 ± 2 mmol·L(-1)·h(-1), P < 0.001) and with GAL (28 ± 3 mmol·L(-1)·h(-1), P < 0.001) than with GLU (13 ± 2 mmol·L(-1)·h(-1)). Liver volumes increased (P < 0.001) with FRU (9% ± 2%) and with GAL (10% ± 2%) but not with GLU (2% ± 1%, NS). Net glycogen synthesis appeared linear and was faster with FRU (8.1 ± 0.6 g·h(-1), P < 0.001) and with GAL (8.6 ± 0.9 g·h(-1), P < 0.001) than with GLU (3.7 ± 0.5 g·h(-1)).

CONCLUSIONS

When ingested at a rate designed to saturate intestinal CHO transport systems, MD drinks with added fructose or galactose were twice as effective as MD + glucose in restoring liver glycogen during short-term postexercise recovery.

The 90-day oral toxicity of d-psicose in male Wistar rats

d-Psicose is a rare sugar present in small quantities in natural products. In a previous study, we showed that d-psicose suppresses increase in plasma glucose and reduces body fat accumulation in rats. Based on acute toxicity testing in rats, d-psicose is classified as an ordinary substance (LD₅₀ = 16 g/kg). Elucidating the effects of sub-chronic feeding of d-psicose in rats is essential before it can be utilized as a physiologically functional food. In this study, male Wistar rats (3 weeks old) were fed diets containing 3% d-psicose or sucrose for 90 days. The body weight gain and intra-abdominal adipose tissue weight did not differ between the sucrose and the d-psicose groups. The weights of the liver and kidneys were significantly higher in the d-psicose group than in the sucrose group. However, no gross pathological findings were evident at dietary doses of 3% d-psicose or were correlated with hypertrophy of the liver and kidney. In a clinical chemistry analysis, the erythrocyte and leukocyte courts were significantly higher in the d-psicose group, but that was not considered to be toxicologically significant. Therefore, the present study found no adverse effects of d-psicose in rats fed a diet containing 3% d-psicosefor 90 days.

A systematic review on the effect of sweeteners on glycemic response and clinically relevant outcomes

BACKGROUND

The major metabolic complications of obesity and type 2 diabetes may be prevented and managed with dietary modification. The use of sweeteners that provide little or no calories may help to achieve this objective.

METHODS

We did a systematic review and network meta-analysis of the comparative effectiveness of sweetener additives using Bayesian techniques. MEDLINE, EMBASE, CENTRAL and CAB Global were searched to January 2011. Randomized trials comparing sweeteners in obese, diabetic, and healthy populations were selected. Outcomes of interest included weight change, energy intake, lipids, glycated hemoglobin, markers of insulin resistance and glycemic response. Evidence-based items potentially indicating risk of bias were assessed.

RESULTS

Of 3,666 citations, we identified 53 eligible randomized controlled trials with 1,126 participants. In diabetic participants, fructose reduced 2-hour blood glucose concentrations by 4.81 mmol/L (95% CI 3.29, 6.34) compared to glucose. Two-hour blood glucose concentration data comparing hypocaloric sweeteners to sucrose or high fructose corn syrup were inconclusive. Based on two ≤10-week trials, we found that non-caloric sweeteners reduced energy intake compared to the sucrose groups by approximately 250-500 kcal/day (95% CI 153, 806). One trial found that participants in the non-caloric sweetener group had a decrease in body mass index compared to an increase in body mass index in the sucrose group (-0.40 vs 0.50 kg/m2, and -1.00 vs 1.60 kg/m2, respectively). No randomized controlled trials showed that high fructose corn syrup or fructose increased levels of cholesterol relative to other sweeteners.

CONCLUSIONS

Considering the public health importance of obesity and its consequences; the clearly relevant role of diet in the pathogenesis and maintenance of obesity; and the billions of dollars spent on non-caloric sweeteners, little high-quality clinical research has been done. Studies are needed to determine the role of hypocaloric sweeteners in a wider population health strategy to prevent, reduce and manage obesity and its consequences.

Tagatose: from a sweetener to a new diabetic medication?

IMPORTANCE OF THE FIELD

Tagatose is a naturally occurring simple sugar that is a more palatable bulk low-calorie (1.5 kcal/g) sweetener. It was approved as a food additive by the FDA in 2003. Tagatose has been studied as a potential antidiabetic and antiobesity medication. In preliminary studies in humans, tagatose has shown a low postprandial blood glucose and insulin response. Its proposed mechanism of action may involve interference in the absorption of carbohydrates by inhibiting intestinal disaccharidases and glucose transport. It may also act through hepatic inhibition of glycogenolysis.

AREAS COVERED IN THIS REVIEW

This article summarizes tagatose Phase I and II diabetes trials. It describes the pharmacodynamics and possible mechanism of action of this agent. Literature from 1974 to 2009 is reviewed.

WHAT THE READER WILL GAIN

Better understanding of the implications of postprandial hyperglycemia. An appreciation of the liver as a target of glucose control. Increased awareness of tagatose, a sweetener, as a potential new medication that operates through improvement of postprandial hyperglycemia.

TAKE HOME MESSAGE

Tagatose is currently being studied as a postprandial antihyperglycemic agent that may be safer with regard to hypoglycemia. Ongoing Phase III clinical trials will provide more definitive answers.

The study on long-term toxicity of d-psicose in rats

D-Psicose is a rare sugar present in small quantities in natural products. In a previous study, we showed that D-psicose suppresses plasma glucose increases and reduces body fat accumulation in rats. Based on acute toxicity testing in rats, D-psicose is classified as an ordinary substance (LD(50) = 16 g/kg). Elucidating the effects of long term feeding of D-psicose in rats will be essential prior to its utilization as a physiologically functional food. In this study, male Wistar rats (3 weeks old) were fed diets containing 3% D-psicose or sucrose for 12-18 months. The rats actually ingested 1.28 g/kg body weight per day D-psicose or 1.22 g/kg body weight per day of sucrose. Body weight gain and intra-abdominal adipose tissue weight in rats fed the D-psicose diet for 18 months were significantly lower than those in rats fed the sucrose diet. Relative weights of liver and kidney were significantly higher in the D-psicose group than in the sucrose group. However, no gross pathological findings were evident at dietary doses of 3% D-psicose or correlated with hypertrophy of liver and kidney. No clinical chemical test value was suggestive of overt D-psicose treatment-related toxicity. Therefore, the present study found no adverse effects at 3% D-psicose in the diet.

Tagatose, a new antidiabetic and obesity control drug

A potentially important new drug for treating type 2 diabetes, tagatose, is now in phase 3 clinical trial. The history, development, additional health benefits, mechanisms of action and the potential for the drug are presented in context with a review of the rapidly growing epidemic of type 2 diabetes and treatments for it. An epimer of fructose, the natural hexose tagatose was originally developed by Spherix Incorporated (formerly Biospherics Inc.) as a low-calorie sugar substitute. Only 20% of orally ingested tagatose is fully metabolized, principally in the liver, following a metabolic pathway identical to that of fructose. Following a decade of studies, tagatose became generally recognized as safe for use in foods and beverages under US FDA regulation. The simple sugar is commercially produced by isomerization of galactose, which is prepared from lactose. Early human studies suggested tagatose as a potential antidiabetic drug through its beneficial effects on postprandial hyperglycaemia and hyperinsulinaemia. A subsequent 14-month trial confirmed its potential for treating type 2 diabetes, and tagatose showed promise for inducing weight loss and raising high-density lipoprotein cholesterol, both important to the control of diabetes and constituting benefits independent of the disease. Furthermore, tagatose was shown to be an antioxidant and a prebiotic, both properties cited in the maintenance and promotion of health. No current therapies for type 2 diabetes provide these multiple health benefits. The predominant side effects of tagatose are gastrointestinal disturbances associated with excessive consumption, generally accommodated within 1- to 2-week period. The health and use potentials for tagatose (branded Naturlose((R)) for this use) are given with respect to current type 2 diabetes drugs and markets. Under an FDA-affirmed protocol, Spherix is currently conducting a phase 3 trial to evaluate a placebo-subtracted treatment effect based on a decrease in HbA(1c) levels. Side effects, contraindications and possibly beneficial new findings will be carefully monitored. It is hoped that early results of the trial may become available by mid-2008. If a subsequent NDA is successful, tagatose may fill a major health need.