Scope A number of findings suggest that zero‐calorie d‐allulose, also known as d‐psicose, has beneficial effects on obesity‐related metabolic disturbances. However, it is unclear whether d‐allulose can normalize the metabolic status of diet‐induced obesity without having an impact on the energy density. We investigated whether 5% d‐allulose supplementation in a high fat diet(HFD) could normalize body fat in a diet‐induced obesity animal model under isocaloric pair‐fed conditions. Methods and results Mice were fed an HFD with or without various sugar substitutes (d‐glucose, d‐fructose, erytritol, or d‐allulose, n = 10 per group) for 16 wk. Body weight and fat‐pad mass in the d‐allulose group were dramatically lowered to that of the normal group with a simultaneous decrease in plasma leptin and resistin concentrations. d‐allulose lowered plasma and hepatic lipids while elevating fecal lipids with a decrease in mRNA expression of CD36, ApoB48, FATP4, in the small intestine in mice. In the liver, activities of both fatty acid synthase and β‐oxidation were downregulated by d‐allulose to that of the normal group; however, in WAT, fatty acid synthase was decreased while β‐oxidation activity was enhanced. Conclusion Taken together, our findings suggest that 5% dietary d‐allulose led to the normalization of the metabolic status of diet‐induced obesity by altering lipid‐regulating enzyme activities and their gene‐expression level along with fecal lipids.

d-allulose is a rare sugar with zero energy that can be consumed by obese/overweight individuals. Many studies have suggested that zero-calorie d-allulose has beneficial effects on obesity-related metabolism in mouse models, but only a few studies have been performed on human subjects. Therefore, we performed a preliminary study with 121 Korean subjects (aged 20–40 years, body mass index ≥ 23 kg/m2). A randomized controlled trial involving placebo control (sucralose, 0.012 g × 2 times/day), low d-allulose (d-allulose, 4 g × 2 times/day), and high d-allulose (d-allulose, 7 g × 2 times/day) groups was designed. Parameters for body composition, nutrient intake, computed tomography (CT) scan, and plasma lipid profiles were assessed. Body fat percentage and body fat mass were significantly decreased following d-allulose supplementation. The high d-allulose group revealed a significant decrease in not only body mass index (BMI), but also total abdominal and subcutaneous fat areas measured by CT scans compared to the placebo group. There were no significant differences in nutrient intake, plasma lipid profiles, markers of liver and kidney function, and major inflammation markers among groups. These results provide useful information on the dose-dependent effect of d-allulose for overweight/obese adult humans. Based on these results, the efficacy of d-allulose for body fat reduction needs to be validated using dual energy X-ray absorption.

Recently, there has been a global shift in diet towards an increased intake of energy-dense foods that are high in sugars. D-allulose has received attention as a sugar substitute and has been reported as one of the anti-obesity food components; however, its correlation with the intestinal microbial community is not yet completely understood. Thirty-six C57BL/6J mice were divided in to four dietary groups and fed a normal diet (ND), a high-fat diet (HFD, 20% fat, 1% cholesterol, w/w), and a HFD with 5% erythritol (ERY) and D-allulose (ALL) supplement for 16 weeks. A pair-feeding approach was used so that all groups receiving the high-fat diet would have the same calorie intake. As a result, body weight and body fat mass in the ALL group were significantly decreased toward the level of the normal group with a simultaneous decrease in plasma leptin and resistin. Fecal short-chain fatty acid (SCFA) production analysis revealed that ALL induced elevated total SCFA production compared to the other groups. Also, ALL supplement induced the change in the microbial community that could be responsible for improving the obesity based on 16S rRNA gene sequence analysis, and ALL significantly increased the energy expenditure in Day(6a.m to 6pm). Taken together, our findings suggest that 5% dietary ALL led to an improvement in HFD-induced obesity by altering the microbiome community.

Allulose has been reported to serve as an anti-obesity and anti-diabetic food component; however, its molecular mechanism is not yet completely understood. This study aims to elucidate the mechanisms of action for allulose in obesity-induced type 2 diabetes mellitus (T2DM), by analyzing the transcriptional and microbial populations of diet-induced obese mice. Thirty-six C57BL/6J mice were divided into four groups, fed with a normal diet (ND), a high-fat diet (HFD), a HFD supplemented with 5% erythritol, or a HFD supplemented with 5% allulose for 16 weeks, in a pair-fed manner. The allulose supplement reduced obesity and comorbidities, including inflammation and hepatic steatosis, and changed the microbial community in HFD-induced obese mice. Allulose attenuated obesity-mediated inflammation, by downregulating mRNA levels of inflammatory response components in the liver, leads to decreased plasma pro-inflammatory marker levels. Allulose suppressed glucose and lipid metabolism-regulating enzyme activities, ameliorating hepatic steatosis and improving dyslipidemia. Allulose improved fasting blood glucose (FBG), plasma glucose, homeostatic model assessment of insulin resistance (HOMA-IR), and the area under the curve (AUC) for the intraperitoneal glucose tolerance test (IPGTT), as well as hepatic lipid levels. Our findings suggested that allulose reduced HFD-induced obesity and improved T2DM by altering mRNA expression and the microbiome community.

D-allulose has recently received attention as a sugar substitute. However, there are currently no reports regarding its association with gastrointestinal (GI) tolerance. Thus, we performed a GI tolerance test for D-allulose in order to establish its daily acceptable intake level. When the dose of D-allulose was gradually increased in steps of 0.1 g/kg·Body Weight (BW) to identify the maximum single dose for occasional ingestion, no cases of severe diarrhea or GI symptoms were noted until a dose of 0.4 g/kg·BW was reached. Severe symptoms of diarrhea were noted at a dose of 0.5 g/kg·BW. Similarly, the GI tolerance test did not show any incidences of severe diarrhea or GI symptoms until a dose of 0.5 g/kg·BW was reached. A correlation analysis of the GI tolerance test for D-allulose and sugar revealed significantly higher frequencies of symptoms of diarrhea (p = 0.004), abdominal distention (p = 0.039), and abdominal pain (p = 0.031) after D-allulose intake. Increasing the total daily D-allulose intake gradually to 1.0 g/kg·BW for regular ingestion resulted in incidences of severe nausea, abdominal pain, headache, anorexia, and diarrheal symptoms. Based on these results, we suggest a maximum single dose and maximum total daily intake of D-Allulose of 0.4 g/kg·BW and 0.9 g/kg·BW, respectively.