In a study on 13 healthy men and women, the researchers found that the group given d-allulose had lower plasma glucose levels and higher free fatty acid levels compared to a control group.
“This indicates that d-allulose has the potential to be an anti-obese sweetener in humans,” the researchers, associated with Nagasaki University and ingredient company Matsutani Chemical Industry, wrote in their report, published in the latest edition of the journal Nutrition.
Rarely found in nature, the fructose epimer d-allulose is considered a ‘rare sugar.’ The ingredient is hot in Japan, where research on it continues to build. One animal study from 2001 found that rats fed a d-allulose diet at 3% to 5% showed decreased body weight and abdominal adipose tissue.
While multiple animal studies have been conducted to explore d-allulose’s potential as an antidiabetic and antiobese sweetener, “no studies thus far have been done to see if and how d-allulose modifies energy metabolism in humans,” the researchers said.
The 13 volunteer study participants passed the screening process, which excluded those with diabetes or metabolic disorders such as cardiovascular diseases.
They were then given 150 mL of water with either 5g of d-allulose from Matsutani Chemical Industry Company or 10 mg of aspartame from Ajinomoto as a control. The ingredients were dissolved and had equivalent sweetness levels. The study was single-blind, which means only the participants were unaware of which beverage they were drinking.
The beverage was drunk with a standardized breakfast meal over 10 minutes—200g of cooked rice and 166g of hamburger. After the meal, energy metabolism was evaluated using a breath-by-breath method and blood sample collection to look at biochemical parameters such as plasma glucose.
Participants then had a one-week wash out period before revisiting the lab to drink the other beverage they didn’t drink in the first lab visit, and go through the same analyses procedures.
After ingesting the d-allulose water, researchers observed a significant increase in fat energy expenditure at 90 minutes compared to the aspartame group. Meanwhile, carbohydrate energy expenditure was significantly lower in the d-allulose group.
“In the present study, free fatty acid was kept at higher levels after an ingestion of d-allulose throughout the experiment, indicating that d-allulose elevated a mobilization of fat from adipose tissue as a fuel,” the researchers wrote.
“This result may support previous studies in which d-allulose decreases adipose tissue weight and upregulates fat oxidation in rats.”
However, it is still unclear where in the body energy expenditure is enhanced or precisely what triggers an increase in energy metabolism, they added.
“At a low dose, d-allulose enhanced postprandial fat oxidation and decreased carbohydrate oxidation in healthy humans,” they concluded.
“This indicates that d-allulose has the potential to be an antiobese sweetener in humans. Further studies in humans are needed to confirm these effects using a large number of individuals with various diseases such as diabetes and obesity and feeding d-allulose over a long-term period.”
Published online ahead of print, https://doi.org/10.1016/j.nut.2017.06.007
d-Allulose enhances postprandial fat oxidation in healthy humans
Authors: T. Kimura, et al.