Stevia plants are native to Brazil and Paraguay. (Norberto Duarte / Getty Images)
Stevia is one of the most popular zero-calorie sweeteners on the market. It distinguishes itself as a “natural” sugar alternative and lures many people looking for a calorie-free, nonchemical sweet fix. Today, an array of products sweetened with stevia stake their claim on supermarket shelves, including juices, smoothies, sodas, cookies, ice cream, and candy. Yet stevia isn’t without a hint of mystery, especially concerning its safety.
The stevia plant
Stevia rebaudiana, the plant from which stevia sweetener is made, is hardly new. Also known as “yerba dulce” or “sweet leaf,” this herb is native to the rainforests of Brazil and Paraguay, where it has been used as a sweetener for over 1,500 years. It’s still grown there today, as well as in Japan and several Asian countries where it’s commonly used. In fact, the stevia plant is gaining popularity in home gardens and at farmers markets. The leaves are dried and used to sweeten beverages, but, paradoxically, are known to have a bitter aftertaste.
Sold under brand names such as Truvia, PureVia and SweetLeaf, stevia sweeteners are quite different from the leaves. They’re made from the plant’s sweetest glycoside (sugar molecule), called rebaudioside A (Reb A), which is extracted by a process that removes the bitter components and leaves an almost pure Reb A extract. The result, which is 200-300 times sweeter than table sugar, is available as a liquid and powder. A typical packet has the sweetness of two teaspoons of sugar, no calories, and almost no carbohydrates. It’s used to sweeten beverages, cereals, yogurt, frosting, and even baked goods — Reb A is heat-stable to 400 degrees.
Animal studies in the 1980s linked stevia with reproductive problems, and with cancer, and it was sold in the U.S. only as a dietary supplement. However, the Food and Drug Administration (FDA) granted Reb A “GRAS” status (generally recognized as safe) in 2008, after the FDA was petitioned by stevia manufacturers. GRAS status allowed only those stevia products made with Reb A to be sold as a sugar substitute or food additive. The FDA still maintains its original ruling on whole-leaf stevia and extracts other than Reb A, such as stevioside, which continue to be sold only as supplements.
Despite the GRAS status, the consumer advocacy group Center for Science in the Public Interest (CSPI), cautions that just because a substance is natural does not mean it’s safe. According to CSPI, the FDA did not perform the amount of testing usually required for GRAS status, and further testing on Reb A is needed. Yet, the Academy of Nutrition and Dietetics maintains that non-nutritive sweeteners can be safely consumed within a balanced eating plan. If you choose to add a touch of sweetness courtesy of stevia, look for Reb A on the ingredient label, as the FDA has not approved other forms of stevia. And — as with all sweeteners — use it in moderation.
Environmental Nutrition is written by nutrition experts. environmentalnutrition.com.