Are Coke's New Stevia Softdrinks Safe to Drink?

strawberries dipped in sweetener known under the aliases stevia rebiana truvia zevia or purevia image
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Image: Cargill

Stevia Hits the Big Time
The low-calorie sweetener hailed as "natural" is coming to a grocery store shelf near you. Coke will start delivering stevia-sweetened Odwalla Mojito Mambo and Odwalla Pomegranate Strawberry nationwide this week and plans to introduce Sprite Green in New York and Chicago before the end of the year. Pepsi is expected to follow with SoBe Lifewater in three flavors (black and blue berry, Fuji apple pear and yumberry pomegranate) as well as a 50% reduced calorie orange juice, Trop50. Both use Cargill's Stevia Sweetener, branded Truvia.

The news is heating up the financial markets: will the natural low-cal sweetener sweeten profits as well? But what interests us is the safety of the new ingredient. The FDA is expected to give stevia-derived sweeteners the status of generally recognized as safe (known as GRAS in the industry), but is GRAS the same as SAFE?

Is Generally Recognized as Safe the Same as Safe?
GRAS is a short-cut to get approval for an ingredient without going through the usual array of studies on the safety and health effects intended to prove an ingredient safe. This short-cut saves industry a lot of money and potential test animals a lot of suffering, so in general it is reasonable that the agencies responsible for food safety have a method to approve ingredients based on the weight of evidence for chemicals which have been in use for many years.

GRAS has another benefit too: advocates of stevia-based sweeteners feared that sweetener manufacturer Cargill would get an approval exclusive to their highly purified version of stevia sweetener, called Truvia. But GRAS status should allow competitors to enter the market. Some stevia based sweeteners and even softdrinks are available on the market now, being marketed under the "dietary supplement" loophole, which allows sale of products with less safety testing.

But if stevia is banned in Europe and not approved for use as a food additive in the US, where is FDA getting information as a basis to decide that stevia is safe? The stevia plant has been used by inhabitants of its native growth zones for centuries. Of course, it has been used as a sweetener, but some tribes using stevia believe chewing the leaf is an effective birth control method. Which leads to obvious questions: if the plant can reduce fertility, it is certainly having health effects.

The Good News and the Bad News
Studies have suggested that stevia sweeteners can have cancer-causing effects and mutagenic effects, as well as reducing male fertility. But all the news is not bad. Preliminary study results also suggest that stevia may have positive effects beyond weight control, including vasodilation (an effect that can be therapeutic for high blood pressure) and improved regulation of blood glucose levels (possibly beneficial in relation to diabetes).

More recent human experience suggesting stevia based sweeteners are safe comes out of Japan, where the natural low calorie stevia sweeteners have been preferred over artificial sweeteners for the past four decades. Food standards agencies in Australia and New Zealand have also published stevia safe intake levels that equate to drinking two cans of diet softdrink per day (see the link for the basis for this calculation).

As is the case with trans-fats and high fructose corn syrup, scientists are about to get a lot more data for continuing studies on the safety of this sweetener. The best advice is moderation in all things, and remember that there are risks with artificial sweeteners as well. Stevia sweeteners offer an "all natural" option for people when the health risks from obesity outweigh other concerns.