SWEETENER UPDATE by tens of millions of people, and needs to be tested in two rodent species in lifetime carcinogenicity studies before it can be accepted as generally recognized as safe,” says Curtis Eckhert, a professor of molecu- lar toxicology at UCLA. He and graduate Sweet...but How Safe? student Sarah Kobylewski co-authored the By David Schardt review commissioned by CSPI. Fertility & Blood “ his is a potential game-changer among T ­zero-calorie sweeteners,” said Lou Imbrogno, While the UCLA toxicologists questioned senior vice president of Pepsi Worldwide Technical whether stevia is ready for prime time, new research has apparently put to rest Operations, in a press release in July. earlier worries that the sweetener could Stevia may be natural—unlike the other major impair fertility or affect blood sugar levels. non-caloric sweeteners. But is it safe...and does In a study sponsored by , “we found no reproductive problems through it like sugar? two generations of rats fed very large doses of rebaudioside A,” says the company’s di- rector of regulatory and scientific affairs.3 Keep Off the GRAS? DNA Damage & Cancer Another Cargill-funded study fed 122 For centuries, stevia leaves have been used The two main sweet-tasting components people with type 2 1,000 mg a day in South America to sweeten beverages. of stevia are rebaudioside A and stevio- of rebaudioside A—two to seven times the And its are used to sweeten side. Two of the new stevia extracts— estimated amount they might consume. in , Paraguay, Japan, Korea, and Coke’s and Pepsi’s PureVia—are After 16 weeks, a long-term measure of 4 China. But in the , stevia can more than 95 percent rebaudioside A. their blood glucose levels didn’t change. be sold only as a . The (Wisdom Natural Brands won’t disclose The UCLA toxicologists didn’t question reason: nagging safety concerns. what’s in SweetLeaf.) the results of either study. This summer, though, several companies Rebaudioside A and told the and Drug Administration are so closely related that any Sweet Nothings that they consider highly purified extracts damaging evidence for either Will stevia join these major no-calorie sugar substitutes? of stevia to be GRAS—Generally Recog- one casts doubt on the safety of nized As Safe. (If an ingredient is GRAS, it the other. ■■ Acesulfame-potassium. Tests conducted in the isn’t considered a and can be The UCLA toxicologists’ first 1970s—one of which suggested an increased cancer risk used without prior FDA approval.) concern: In some test tube and in female rats—were of mediocre quality. But they may have jumped the gun, ac- animal studies, stevioside (but ■■ (NutraSweet, Equal). Judging by the cording to a review prepared for the Center not rebaudioside A) caused muta- results of two recent rat studies, it may slightly increase for Science in the Public Interest (publisher tions, chromosome damage, or cancer risk. of Nutrition Action) by toxicologists at the DNA breakage. ■■ (Sweet’N Low). In animal studies, it has University of California, Los Angeles. For example, when Brazilian caused cancer of the urinary bladder, uterus, ovaries, skin, These are the major stevia sweeteners researchers added stevioside to blood vessels, and other organs. that are being rushed to market: the drinking water of lab rats, ■■ (). It appears to be safe, but may the investigators found DNA ■■ Truvia (from Coca- and agricultural not appeal to people who want a “natural” sweetener. behemoth Cargill). Cargill is rolling out breakages in cells in the animals’ 1 Sucralose is made by chlorinating sugar molecules. Truvia as a tabletop sweetener. Coca-Cola blood, liver, spleen, and brain. has plans to use it in soft drinks. If a chemical causes DNA damage, the second question is whether it ■■ PureVia (from Pepsi-Cola and Whole The Bottom Line causes cancer. It’s reassuring that in two Earth Sweetener Co.—a subsidiary of the studies that fed stevioside to rats for two Using stevia occasionally—to sweeten a company that manufactures the Equal years (most of their lives), tumors didn’t in- cup of tea, for example—is probably safe. brand of aspartame). Whole Earth plans crease.2 But no one has fed rebaudioside A (Taste is another matter. Some of our to start selling PureVia as a tabletop to rats to see if it causes tumors. testers thought Truvia tasted like sugar. sweetener this fall. PureVia-sweetened What’s more, substances can cause Others found it bitter.) Pepsi drinks will come later. cancer in one animal and not another, so But if Coke and Pepsi add stevia to their ■■ SweetLeaf. Wisdom Natural Brands the FDA recommends testing compounds diet drinks, millions of people would be started selling SweetLeaf sweetener in like stevia—which could be ingested at exposed to large amounts of the sweetener. June. high levels by a huge number of people— Until companies (or, better yet, an inde- Cargill and Whole Earth Sweetener in two species (typically rats and mice). pendent authority like the federal govern- have asked the FDA to review the safety But no one has published studies looking ment’s National Toxicology Program) do evidence before Coke and Pepsi start add- at whether rebaudioside A or stevioside more testing, there’s no way to tell whether ing stevia extracts to diet drinks. causes cancer in mice. that would increase the risk of cancer. “Rebaudioside A is likely to be consumed 1 ©fotolia.com: travis manley (bottle), meailleluc.com (powder). Photo illustration: Jorge Bach. That’s good news, because the UCLA Food Chem. Toxicol. 45: 662, 2007. toxicologists are concerned about wheth- 2 Food Chem. Toxicol. 46: S1, 2008. More on the Web 3 Food Chem. Toxicol. 46: S21, 2008. Photos: er stevia extracts could cause cancer. 4 www.nutritionaction.org/stevia Food Chem. Toxicol. 46: S47, 2008.

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