D-Allulose altered hepatic metabolites, especially those related to the lipid metabolism processes, such as the fatty acid β-oxidation, cholesterol, bile acid, and glucuronic acid/xylulose pathways.

D-allulose is a rare sugar that has been reported to possess anti-hyperglycemic effects. In the present study, we hypothesized that d-allulose is effective in attenuating the progression of diabetic nephropathy in the Otsuka Long-Evans Tokushima Fatty (OLETF) rat model of type 2 diabetes mellitus. Drinking water with or without 3% d-allulose was administered to OLETF rats for 13 weeks. Long-Evans Tokushima Otsuka rats that received drinking water without d-allulose were used as non-diabetic control rats. d-allulose significantly attenuated the increase in blood glucose levels and progressive mesangial expansion in the glomerulus, which is regarded as a characteristic of diabetic nephropathy, in OLETF rats. d-allulose also attenuated the significant increases in renal IL-6 and tumor necrosis factor-α mRNA levels in OLETF rats, which is a proinflammatory parameter. Additionally, we showed that d-allulose suppresses mesangial matrix expansion, but its correlation with suppressing renal inflammation in OLETF rats should be investigated further. Collectively, our results support the hypothesis that d-allulose can prevent diabetic nephropathy in rats.

Age-related physical and cognitive decline may be ameliorated by consuming functional foods. D-Allose, reported to have multiple health benefits, may temper aging phenotypes, particularly brain function. We investigated whether D-allose supplementation improves cognitive function. A standard battery of behavioral tests was administered to 18-month-old male mice after consuming diet containing 3 % D-allose for 6 months. Following a wire-hanging test, an open-field test, Morris water maze, fear-conditioning, and an analgesia test were sequentially performed. Bone density and strength were assessed afterwards. Possible mechanism(s) under-lying memory changes in hippocampus were also examined with a DNA microarray. D-Allose failed to influence muscle strength, locomotor activity and anxiety, fear memory, or pain sensitivity. However, D-allose improved hippocampus-dependent spatial learning and memory, and it may contribute to increase bone strength. D-Allose also changed the expression of some genes in hippocampus involved in cognitive functions. Long-term D-allose supplementation appears to modestly change aging phenotypes and improve spatial memory.

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.

D-Allulose (D-psicose) is a rare sugar and a C-3 epimer of D-fructose. D-Allulose has been reported to have several health benefits via its alteration of both glucose and lipid metabolism. It was previously reported that D-allulose alters the hepatic metabolomic profile. Although the kidneys are crucial organs in metabolic regulation, the effects of D-allulose on renal metabolism have not yet been established. Therefore, this study was designed to capture the overall metabolic response in the kidneys to D-allulose. This was done by providing an AIN-93G diet to Wistar rats, with or without 3 % D-allulose, for four weeks. Renal tissue and blood samples were collected after a 3-hour fasting for evaluation of the renal metabolic profile and their related plasma parameters. D-Allulose increased renal weight without changes in the plasma indices associated with reduced renal function. Metabolic profiling identified a total of 264 peaks. As the contribution rate was too low in the principal component analysis results of the metabolic profiling results, we evaluated the metabolites that were significantly different between two groups and identified 23 up-regulated and 26 down-regulated metabolites in the D-allulose group. D-Allulose also had significant influence on several metabolites involved in glucose metabolism, amino acid metabolism, and purine metabolism. Moreover, the levels of trimethylamine N-oxide and symmetric dimethylarginine, which are associated with several diseases such as chronic kidney disease and cardiovascular disease decreased following D-allulose diets. This study showed that D-allulose affects the renal metabolic profile, and our findings will help elucidate the function of D-allulose.