Gastrointestinal tolerance of D-allulose in healthy and young adults. A non-randomized controlled trial

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.