Stevia/Truvia/PureVia's Safety

About this time last year I blogged about Stevia. Stevia is a plant native to South and Central America and its extracts are 300 times sweeter than sugar without the calories of sugar. This time last year, the use of Stevia in food was banned in Canada and the United States because of a lack of evidence that it was safe.
However, in December 2008, the American FDA approved rebaudioside A, the sweet extract of the stevia plant, a move that has been called "President Bush's parting gift to the soda industry". Canada and the European Union have not approved the use of Stevia in food.

What changed?

The FDA received two notices that rebaudioside A was 'Generally Recognized as Safe' (GRAS). Who submitted these GRAS notices?
Two corporate giants with evident interest in using the stevia extract: Cargill Inc and Whole Earth Sweetener.
These GRAS notices informed the FDA that their ingredients were safe and didn't need pre-market approval... leading to, according to a review prepared for the Center for Science in the Public Interest (CSPI), the following products being rushed to market too early:

Truvia- from Coca-Cola and Cargill- a tabletop sweetener. Moreover, Sprite Green (from Coca-Cola) is out on the market already and Coca Cola plans to use it in Coke soft drinks and plan to release new Odwalla juice drinks with the sweetener.

PureVia- from Pepsi-Cola and Whole Earth Sweetener- a tabletop sweetener. Pepsi Co has released Trop50 (Tropicana) containing the sweetener and will launch at least 3 new flavours of SoBe Lifewater.

SweetLeaf- Wisdom Natural Brands started selling SweetLeaf sweetener.

Why the concern?

Firstly, the research was industry-sponsored raising questions about the objecticity of the science - authors of the studies are scientists from Cargill and Coca-Cola (or paid by Cargill). The FDA did not follow-up.

Some independent studies have found that the stevia extracts caused mutations, chromosome damage or DNA breakage. Although in 2 studies in which one of the extracts, stevioside, was added to drinking water and fed to rats for 2 years, there was no increase in tumors. However, the most popular extract, rebaudioside A (TruVia and PureVia are 95% rebaudioside A), wasn't tested!
Furthemore, Stevia was only tested on one animal and usually, it should be 2.
Other reports found ill effects to the rats' reproductive systems: male rats fed high doses of the stevia exract for 22 months had lower sperm production and femal hamsters had fewer and smaller babies. However, a Cargill-sponsored study found no evidence of reproductive problems through 2 generations of rats fed very large doses of the stevia extract.
Evidently, more research is waranted but, according to a senior nutritionist at CSPI, there was probably a lot of pressure put on the FDA to approve the new sweetener.

The Stevia products are being marketed as natural because they come from a plant. To underline their natural claims, the stevia products are packaged in green. However, be aware that stevia is also being blended with other sweeteners: the makers of Splenda just introduced Sun Crystals, a mix of sugar and stevia. Stevia is also being added to some soft drinks containing aspartame.

Japanese manufacturers have been using stevia since the 70s but they don't consume nearly as much soda as North Americans.

Bottom Line:
According to the CSPI, the occasional use of a stevia product to sweeten your tea or coffee is probably safe (although taste is another matter as it has been said that there is a bitter aftertaste). However, until more reserach is done, there's no way to tell whether larger amounts will increase the risk of cancer (If Coke and Pepsi add stevia to their diet drinks, millions of people will be exposed to large amounts...) .
The general recommendation when it comes to sweeteners is to limit your intake to 2-3 sweetener-sweetened products a day.
For more general information on sweeteners, click here.