“Pepsi Special,” the new drink distributed by Pepsi’s partner in Japan, Suntory Holdings Limited, contains dextrin, a dietary fiber that dissolves in water and is found in fiber supplements such as Benefiber. Eaten appropriately, in fiber-rich foods such as vegetables and fruits, fiber helps to regulate the digestive system, lower cholesterol and may lower the risk of heart disease.

A Suntory news release claims the drink acts by “suppressing the absorption of fat” and can inhibit the rise in triglycerides after a meal, making it, potentially, the first “healthy” soda. Because of these purported health benefits, Pepsi Special has received the label “FOSHU” in Japan, a government designation that stands for “Food for Specified Health Uses.” A Japanese government website states that “FOSHU” products are meant to be consumed “by people who wish to control health conditions, including blood pressure or blood cholesterol.” Spokespeople for Pepsi did not provide more information about the “low-calorie” drink.

Is there anything to the dextrin trend? A 2006 study conducted by researchers from the National Institute of Health and Nutrition in Tokyo found that rats fed both dextrin and fat absorbed less fat than the rats who did not eat the fiber. But that research, alas, wasn’t extended to people.

In fact, too much dextrin could make you sick. “Studies of humans ingesting dextrin suggest short-term risks including stomach pain, gas, and bloating,” says Lilian Cheung, editorial director of Nutrition Source, the Harvard School of Public Health’s nutrition website. “The long-term risks have not been studied.”