The term prebiotics has been part of the yogurt landscape for years but now prebiotic sodas are getting some attention. But there are obstacles that may keep more brands from moving into the category, notes a recent report.

To define, first, a prebiotic is “a nondigestible food ingredient that promotes the growth of beneficial microorganisms in the intestines,” according to a Google definition. That usually means fiber and, sure enough, prebiotic sodas have fiber in them.

“Prebiotic sodas have become a phenomenon, even if their ingredients remain a mystery to most consumers. Many industry insiders feel brands like poppi and OLIPOP are here to stay,” reports The Food Institute, an industry news site.

“Prebiotic sodas have substantial long-term potential,” Todd Redmon, partner at PA Consulting, told The Food Institute. “Scientific research continues to uncover the benefits of prebiotics for digestive health, immunity, and even mental health.”

Poppi (it may spell its name in all lower-case but here sentences start with capital letters) is the leading brand in the $100 million-in-annual sales category which has about a dozen brands already, the Food Institute reports.

But consumers largely don’t know what’s in these drinks and their price is relatively high, so experts wonder how popular they will become.

There also seems to be something intrinsically odd about drinking a carbonated beverage to keep regular.