the effectiveness of a diet containing D-allulose in patients with type 2 diabetes

In a recent study published in Nutrientsresearchers evaluated the effectiveness of diabetic diets containing D-allulose in patients with type 2 diabetes (T2D).

Background

Diabetes is widespread throughout the world, most cases of which are type 2, characterized by insulin resistance and decreased insulin secretion. Basic therapy for T2DM includes dietary modifications, regular physical activity, and medication; however, lifestyle habits are most important in reducing the burden of diabetes.

Excess sugar consumption increases the risk of obesity, cardiovascular disease and diabetes. Artificial sweeteners have been used as safe alternatives to sugar in diabetic patients; however, there are concerns about exacerbations of glucose metabolic reactions by artificial sweeteners. D-allulose is the C-3 isomer of D-fructose, a rare sugar with proven anti-obesity and anti-diabetic properties.

About the study

In this prospective, randomized, single-blind, crossover comparative study, researchers investigated whether diets containing D-allulose could improve glycemic control in patients with T2DM.

The study included 24 people hospitalized at Kagawa University Hospital from December 2019 to August 2022. Blood glucose levels were measured using an intermittent continuous glucose monitoring (isCGM) system . Only hospitalized patients with T2DM aged 20-80 years were included with glycated hemoglobin (HbA1c) values ​​≥ 6.50% willing to participate.

Participants were divided into two groups: A and B. Individuals in group A were fed diabetic diets three times a day for two days. After a washout period of ≥1.0 days, participants received diabetic diets containing D-allulose three times daily for two days. Diet was reversed in group B individuals. Total daily energy intake was determined according to the 2019 Diabetic Care Guidelines of the Japan Diabetes Society.

C-peptide immunoreactivity (CPR) and insulin immunoreactivity (IRI) were measured. The primary endpoints were postprandial blood glucose (PPG) spikes after consumption of standardized diabetic diets and those including 8.50 g of D-allulose.

Secondary endpoints of the study included PPG trends assessed using the isCGM system, duration of blood glucose values ​​within the target range of 70.0-180.0 mg per dL [percent time in range (TIR)]the duration of hypoglycemic episodes (below 70.0 mg/dL) which was less than the TIR [percent time below range (TBR)]and that of hyperglycemic episodes (greater than 180.0 mg per dL) exceeding the TIR [percent time above range (TAR)].

Safety endpoints included changes in the number of diarrheal episodes. In addition, participants completed questionnaires verifying satisfaction, smell, seasoning and coloring. The team excluded people taking α-glucosidase inhibitors, those with a positive history of serious adverse events after taking D-allulose, and those with serological creatinine ≥ 1.50 mg/dL (indicating a severe renal dysfunction).

Additionally, pregnant and breastfeeding women, people in other trials, and those deemed unsuitable for the study by physicians were excluded. Linear mixed effects modeling was used for the analysis.

Results

Initially, 45 people were screened for eligibility, 21 who did not meet the inclusion criteria were excluded, and 24 were enrolled in the study. However, four people dropped out of the study, reducing the final sample size to 20. The mean peak PPG values ​​for the D-allulose-containing diet and the standard diabetic diets were 173.0 and 191.0 mg/dL, respectively.

The results indicated that diabetic diets containing D-allulose significantly reduced PPG levels in patients with T2DM compared to energy-strict diabetic diets. In addition, a protective effect was observed on the endogenous insulin secretion capacity of the pancreas due to a decrease in insulin requirements. Carryover effects were negligible, with no washout problems.

D-allulose regimens reduced area under the curve (AUC) from 0.0 to 180.0 min-PPG levels (25,408 vs. 27,550 mg-min/dL) and %TAR (30% vs. 21%) . However, no statistically significant changes were observed in TIR ratios (68% vs. 74%) and TBR values, with no increase in the frequency of hypoglycemic episodes (2.10% vs. 5.0%).

CPR levels decreased significantly with reductions in blood glucose readings. Non-significant differences in satisfaction, smell, seasoning and coloring were observed. There were no safety issues with nonsignificant changes in the frequency of diarrheal episodes. None of the participants had any complaints related to smell or taste, and none could distinguish between the two diets.

Reported mechanisms underlying the hypoglycemic effects of D-allulose include inhibition of monosaccharide uptake by small intestinal cells, promotion of glycogen synthesis through activation of glucokinase in the liver, pancreatic protection and improving the pancreas’ ability to secrete insulin. D-allulose may improve glucose tolerance and decrease appetite by increasing GLP-1 (glucagon-like peptide-1) secretion and altering central nervous system (CNS) activity through the vagus nerve.

Based on the study results, diabetic diets including 8.50 g of D-allulose effectively improved postprandial blood glucose levels, indicating that D-allulose can improve glucose tolerance and protect pancreatic β cells in patients with T2DM. However, further research, including larger sample sizes and longer follow-ups, is needed to increase the validity of the study results.