The Zero-Calorie Sweetener Stevia Arrives

There's a new sugar substitute on the market with a really sweet pitch: zero calories, zero carbohydrates, and zero chance of a spike in blood sugar levels.

Several companies are just out with new products derived from the leaves of the Latin American herb stevia, which contain a substance hundreds of times more potent than sugar. Arizona-based Wisdom Natural Brands was the first to start aggressively marketing packets of its powdered SweetLeaf earlier this summer. Agribusiness giant Cargill, working in collaboration with Coca-Cola, followed with Truvia. And PepsiCo, with Whole Earth Sweetener Co., has developed a new line of beverages sweetened with a stevia product called PureVia. "Soon you'll see stevia in pretty much every food product you can imagine," predicts Oscar Rodes, the founder of Texas-based producer Stevita Co., who is betting the herb could eventually account for 20 percent of the overall sweetener market.

Stevia's already a hit with fans of alternative medicine, since it has long been sold by health food stores as a dietary supplement. (The Food and Drug Administration hasn't yet endorsed the safety of the new products as food additives, but the companies claim they've met requirements to establish stevia as "generally recognized as safe" by scientists.) Boosters tout all those zeros as evidence that the herb is far more healthful than sugar and artificial sweeteners. A packet of sugar has about 11 calories, 3 grams of carbohydrates, and an estimated "glycemic load" of 2, for example. Dietitians recommend keeping your glycemic load, a measure of how much particular foods raise blood sugar levels, below about 100 a day. A packet of sucralose (Splenda) has 3 calories, 1 gram of carbohydrates, and a glycemic load of 1, according to NutritionData.

Indeed, some research suggests that stevia may improve health. Jan Geuns, a biologist in Belgium who has organized symposiums to explore the substance's pharmacological effects on humans, points to two Chinese studies that have found it can significantly lower blood pressure among people with mild hypertension. Danish researchers have reported that stevia seems to reduce blood glucose levels among patients with type 2 diabetes. But the effects were seen only at doses far greater than those for stevia used as a sweetener, Geuns cautions, so the typical user would experience little effect.

The dietary supplements have been slow to catch on with mainstream consumers, partly because of a bitter licorice aftertaste. Makers of the new sweeteners claim to have found ways around that; since the degrees of processing and purity vary significantly—some products contain added flavors, bulking agents, or fiber—consumers may want to try several brands. For the best taste, Rodes recommends using products that are at least 95 percent pure; Geuns says to look for products rich in a substance called rebaudioside A.

It's not just taste that has hampered consumer acceptance; the herb's been trapped in a regulatory limbo. Since the '60s, a trickle of animal studies has suggested that stevia might cause potentially cancerous mutations or reproductive problems. Though the studies' methodologies were criticized and stevia had a good safety record in countries where it was widely used at the time, such as Japan, regulators imposed an import ban in 1991. The stevia industry howled, charging that artificial-sweetener makers just wanted to clear the market of competition.

Rigorous research. In 1994, a new law that revamped the way foods are regulated led to a lift of the import ban and put stevia in the odd position of being considered safe if marketed as a dietary supplement but not if used in foods or drinks. "It's a completely absurd and confusing situation for consumers," says James Turner, a partner at Swankin & Turner, a consumer rights law firm based in Washington, D.C., who has expertise on the regulation of sweeteners. The intent, according to the FDA, is to prove stevia safe through rigorous research before people start widely consuming it in food.

In the case of Truvia, the research has been done, says Ann Tucker, a spokesperson for Cargill. In May, the company notified the FDA that a series of studies had affirmed Truvia's safety. "We did an absolutely thorough job," says Tucker, "and published the results in peer-reviewed scientific journals." She cautions that the findings apply only to Cargill's rebaudioside A extract. In June, Wisdom Natural Brands announced that two independent expert panels that reviewed the safety of SweetLeaf gave it a thumbs up.

Updated on 08/29/08: An earlier version of this story did not reflect a recent announcement of a new line of beverages by PepsiCo and Whole Earth Sweetener. This version also explains in greater detail the regulatory process as it applies to stevia.