The Tao of Stevia

What fro-yo addict worth her Pinkberry card wouldn’t kill for a zero-calorie sweetener that doesn’t cause bladder cancer [2] or carry the faint taste of rubber? And if it comes straight from the earth and not from the corridors of a scary laboratory? Why, even better.

That’s the edge stevia-derived Rebiudioside-A, the latest entrant in the zero-calorie sweetener market, has claimed over its pastel competitors: It’s totally 100-percent natural. Or so say the labels on Truvia and other newly popular sweeteners that use Reb-A, a “high purity” component of stevia, as their main ingredient. But is stevia really as pure and natural as manufacturers’ labels would have us believe? And, not unimportantly, how does it taste?

Indigenous South Americans have known of the sweetening powers of Stevia rebaudiana, which comes from the leaves of a South American shrub, for centuries, and the Japanese have cultivated it since the 1970s.

But stevia’s record in this country has always been spotty. It was banned by the FDA in 1991 after a study on rats showed adverse effects on fertility and even possible DNA damage. In 1995, four years after declaring stevia an “unsafe food additive [3],” the FDA softened this controversial ruling and allowed the importation of stevia, but only as a “dietary supplement,” meaning you had to hunt it down in the vitamin aisle. More than a decade later—in an astonishing stroke of corporate coincidence, soon after Pepsi, Coke, and related titans got involved—the FDA changed its tune again, granting Reb-A GRAS (“generally recognized as safe”) status.

And just like that, with a speed befitting its own scene in The Informant! [4], Reb-A was everywhere. Within nine months of gaining FDA approval last December, stevia derivatives had claimed about 10 percent of the sugar-substitute market. Market research [5] has identified more than 110 new food, drink, and personal-care products made with stevia in 2009 alone. A recent tabulation put the stevia market at $100 million [5] this year; another study predicted that this figure will grow to $700 million in the next five years. For now, Reb-A is still expensive—it costs more than twice as much as high-fructose corn syrup—but analysts expect the price to drop with the spike in demand.

But not everyone is feeling the stevia fever. Advocacy groups like the Center for Science in the Public Interest (CSPI) have objected to the FDA’s rushed approval of Reb-A [6]. Last summer, CSPI demanded more extensive testing before the release of Reb-A on to the marketplace, but by then there was too much money on the table to stem the tide.

These misgivings have done little to deter the many food and beverage makers scrambling to claim their corner of the stevia market. The two biggest-money entrants are Truvia [7] (“Nature’s Calorie-Free Sweetener,” the lovechild of Cargill and Coca-Cola) and PureVia [8] (“All Natural Zero Calorie Sweetener,” brought to you by Pepsi and the makers of Equal). There’s also Sweet Leaf [9] (“America’s first 100% Natural Alternative to Artificial Sweeteners”), Sun Crystals [10] (a combination of “cane sugar and the stevia plant—two of nature’s wonders under the same sun”), Stevia Extract in the Raw [11] … and this is just at my local Safeway.

So how do all these new stevia permutations taste? If, as it’s been anointed, Reb-A really is the “holy grail” of the no-cal-sweetener market, it has to be pretty delicious—not that the extreme nastiness of aspartame did much to dim its popularity.

Pure stevia is about 200 times sweeter than sugar. It’s also known for its distinct, slightly metallic aftertaste, which is probably another reason Coke, Pepsi, et al., have combined Reb-A with the fruit sugar erythritol—a low-calorie sugar alcohol found in fruits and, for the last 20 years, manufactured for use in food—and other “all-natural” additives.

I loaded up on a range of Reb-A-based sweeteners, then assembled a panel of six artificial-sweetener experts, two of them diabetic, to judge. (I considered myself unfit for this particular challenge, since my lifelong passion for sugar [12], however excessive on occasion, brooks no imitators.) We mixed the various sugar substitutes with coffee and green tea. And though we didn’t have the pleasure of sampling the stevia-sweetened dried strawberries [13] written about on DoubleX, we did try out several of the new diet drinks that feature the revolutionary sweetener. A neighbor even made pear muffins with some stevia I passed along.

Overall, my taste-testers weren’t yet ready to convert: Regardless of format, most found the aftertaste off-putting. The green tea was reminiscent of children’s cough syrup, and Tropicana’s Trop50 [14] 42-percent-juice drink, the panel agreed, tasted “like orange juice served on domestic flights, only a lot more disgusting.” But while Vitamin Water 10 [15] was “only slightly more disgusting than regular Vitamin Water,” SoBe Fuji Apple Pear Lifewater [16] tasted “like melted Nerds”—and not in a good way. The baker liked the look of her stevia-sweetened muffins but found the sweetness too overpowering to repeat the experiment.

Only one of the testers said she would switch from Splenda to her favorite of the bunch, PureVia, in her morning coffee. Another guy—who has been diabetic for 25 years and “lives on artificial sweeteners”—was a big fan of the Vitamin Water 10 but found the SoBe drinks too sickly-sweet even for him. Most couldn’t get over the aftertaste, which does seem to be one of the few remaining hurdles on Reb-A’s road to world domination.

Another question, not to be underestimated, is that of safety: Are stevia derivatives any better than Splenda, or are they fated to become the next saccharin?

As the CPSI report makes clear [17], the stevia Pepsi and Coke are peddling is not the same stevia found in the wilds of Paraguay. The FDA has approved only Reb-A, a “high-purity” stevia glycoside [18]. (Stevia rebaudiana’s other main glycoside, stevioside, has yet to receive GRAS clearance, and whole-leaf stevia—the kind native Paraguayans used to sweeten yerba mate and to treat heartburn and other minor digestive complaints—is still relegated to the second-class citizenship that is the nutritional-supplement aisle of the grocery store.)

The primary ingredients in Truvia, PureVia, and most of the other stevia-based sweeteners now crowding the sugar aisle are the Reb-A extracted from whole-leaf stevia and the industrially processed fruit sugar erythritol (which is in the same family as the xylitol and sorbitol used in sugar-free gums).

Because the 1980s lab tests that resulted in stevia’s banishment were conducted on the whole-leaf form, the big players in the no-cal sweetener market are going to great lengths to differentiate their sweetener from straight-up stevia. Their product is not actual potentially toxic stevia, but a purified, processed extract of stevia. “They’ve tried, I don’t think overtly, to claim that any negative component could be related to what else is in the stevia leaf, in the part that they don’t use,” dietician Ashley Koff [19] said in an interview.

But how much do we know about the safety of Reb-A? Not nearly enough, the CPSI believes.

One pro-stevia argument has always been that people have consumed it for centuries. Which is true—the sweetener has a long history in South America. The difference is that natives used the full leaf, either heated up and made into a syrup, or ground into a powder. By comparison, people have been consuming Reb-A for approximately nine months.

Another big difference is the quantity involved. Native South Americans weren’t mainlining the sweeteners around the clock, as their neighbors to the north are wont to do. If Reb-A lives up to manufacturers’ expectations, we’ll soon be chugging it down in our morning O.J., our mid-afternoon coffee, our post-gym sports drink.

And, as Ashley Koff pointed out, whether natural or processed, the overuse of sweeteners has a more general downside. Reliance on pure stevia, or Reb-A, or Nutra-Sweet, or whatever, has the effect of “acclimatizing the taste buds to an artificial level of sweetness,” Koff said. So the more stevia you use, the more stevia you’ll want. At the same time, Koff said, “You might also start craving more salt.” If only there were a way to get all the delicious flavor—and none of the deadly sodium—of real salt ... bring on the Nu Salt [20]!