Stevia is all-natural and calorie-free, but is it safe?
NUTRITION LAB
The sweetener is banned from food products in the U.S. due to toxicity fears. But the findings of several recent studies suggest otherwise.
Stevia followers are a diverse bunch, including health nuts and food-industry magnates. The draw? The sweetener is all-natural and naturally calorie-free. But "natural" doesn't necessarily mean safe, and scientists have long struggled to make sense of early evidence hinting that stevia could be toxic. A series of studies published last month in the journal Food and Chemical Toxicology put that question to the test for one type of stevia-based sweeteners.
Stevia, a South American shrub, has leaves up to 300 times sweeter than table sugar. Extracts have been available as a dietary supplement since 1995. It's a popular food additive in Japan, Brazil and its native Paraguay, but in the U.S., where the Food and Drug Administration has determined there isn't sufficient proof it's nontoxic, stevia is banned from such uses. (Exceptions are made for food and drink items billing themselves as dietary supplements, such as the stevia-sweetened diet drink Zevia.)
Stevia sweeteners: An article in Monday's Health section about no-calorie sweeteners derived from the plant stevia said supermarket sales tests of stevia-derived rebaudioside A (sold as Truvia) were being conducted in New York with the blessing of the Food and Drug Administration. Permission from the FDA was not required for Truvia to be sold. However, Truvia is the subject of an FDA review process that will determine whether the product is safe and allowed to remain on the market.
Stevia sweeteners: An Aug. 25 Health article on no-calorie sweeteners derived from the plant stevia stated that supermarket sales tests of stevia-derived rebaudioside A (sold as Truvia) were being conducted in New York with the blessing of the Food and Drug Administration. Permission from the FDA was not required for Truvia to be sold. However, Truvia is the subject of an FDA review process that will determine whether the product is safe and allowed to remain on the market.
Scientists began studying stevia in the lab roughly 40 years ago, and the first findings gave food safety officials in several countries pause. A 1968 study in female rats showed that drinking a concoction of stevia leaves and stems significantly reduced fertility. A 1985 study, published in the Proceedings of the National Academy of Sciences, showed that steviol, a breakdown product of stevia, might cause genetic mutations. (In Paraguayan traditional medicine, stevia is used to lower blood sugar and as a contraceptive.)
Evidence of genetic and reproductive toxicity was sufficient to inspire a ban on the sweetener in the U.S. since the 1970s. (The 1994 Dietary Supplement Health and Education Act made it legal to sell stevia as a dietary supplement only, as long as it's not an ingredient in food.) But the research on which the FDA based its long-ago decision may now be out of date. In the last decade, countless studies have revisited stevia, often using purer extracts.
The more-recent research has largely focused on purified forms of the two main chemicals responsible for the stevia plant's sweetness: stevioside and rebaudioside A. Findings from some studies -- still few in number -- have resulted in a perhaps overstated claim: that stevia lowers blood pressure.
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