Cargill's new sweetener won't kill you or make you go sterile ... probably

I like nature more than the next guy, but have turned a skeptical eye towards "natural" sweeteners. Nightshade's natural, and so are box jellyfish. You won't catch me putting either in my yerba mate. But now a Minnesota company is hoping I'll sweeten the beverage with a new "natural" product that has inspired past concern over health effects.

Yerba mate's my beverage of preference because I'm allergic to coffee, and because I enjoy its unique, bracing taste. For years, people have been drinking the South American tea -- and masking the taste with leaves from a plant called stevia, an herb that's sweeter than sugar.

Minneapolis-based Cargill has planned for some time to introduce a no-calorie sweetener using the stuff, and announced new research last week that it claims proves the product's safety. Cargill's planned product goes by the proprietary name Rebiana.

While legal as a supplement here and common in countries like Japan, the Food and Drug Administration hasn't approved stevia for use as a food additive due to concerns over cancer, reproductive health and other health problems. As the Wall Street Journal reports:

Stevia isn't approved for use as a food additive in the U.S. Studies over the past two decades on its health effects have logged in a number of problems, from research in 1985 finding potential mutations in the livers of rats to concerns about fertility problems in men.

The herb has staunch advocates, as any Google search reveals. But scientific study results (and reviews) are much more mixed than the rosy believers hold. The Center for Science in the Public Interest has even-handed commentary, including links to the studies, here.

While troubling, none of these studies were conclusive. To get a watchdog group's take on Cargill's new information, I called David Schardt, senior nutritionist for CSPI, who said that the FDA has been right not to approve stevia in food so far.

"We can't just put anything into food: it has to be safe. And it's up to companies to provide that evidence," he said. "Until now, no one has done that research."

Throughout this year, scientists will be weighing in on the research. Cargill's position, according to the FDA -- the company didn't return my calls -- is that past health risks identified in studies may have been due to impure extracts of stevia. They believe their product uses "a purified constituent of stevia that they have extensively studied for safety," said FDA spokesperson Michael Herndon. It is not the same ingredient as whole stevia leaf.

This safety information needs to confirmed by careful examination of the studies. "If that's true, that would be good news -- we'd have a non-caloric, natural sweetener, which people would like," said Schardt. "That would be good news for everybody."

But can we really trust industry-sponsored science? "One always has to keep it in mind, but you have to be realistic," Schardt says. "Who else is going to this research?"

Since Cargill's research was keenly focused on this particular product, even if the FDA grants Rebiana approval, this will not make other forms of stevia legal as food additives. This is significant because numerous competitors have stevia products they would like to bring to market.

According to the FDA, Cargill has sent them an notice arguing that the new study means Rebiana should be "Generally Recognized as Safe" under the law. The federal government now has 180 days to respond, which is quicker than many FDA processes -- meaning this new sweetener could be on the market by winter.