(More Plant Freak News, by request. Still knitting, still spinning, still in denial about move. Blah blah.)
Stevia is the new big-deal ooh-ah in industrial agriculture. It is a sweetener; not quite artificial, but not quite sugar either. Cargill is marketing it under the name "Truvia" and that's probably the state most of us have encountered it in (except for you wild people growing it).
Stevia is a shrubby little group of plants in the Aster family, meaning they are related not only to asters, but sunflowers, safflower, lettuce, artichokes, and, well, asters are one of the largest families of flowering plants, so there's a hell of a lot of them. Stevia in particular is native to central America, and has been used as a sweetener, medicine, and food, by the people in the area for time out of mind. It has been known in the west/European-settled world since 1899.
I was told in hort class that one of the things that really slowed the industrialization and widespread use of Stevia was the domestication of it. Supposedly, the plant is very sensitive to daily light cycles and won't grow well in areas with markedly different cycles. However, I can't find any mention of that quirk on the internet in articles I'm looking at, and all my botany books are in boxes in Ohio, so take it as you will.
The big, huge, raging controversy over Stevia is the same one that rages around all the 'artificial' sweeteners: safety. Rather, whether the sugar lobbyists are having the other sweeteners declared unsafe to cover their own asses. Stevia has been used for over thirty years in Japan with no ill effect, yet in 1985 (at that point Japan had been using it for fourteen years), the FDA declared it unsafe in the US. This prompted people to accuse the FDA of taking sugar industry money, and the snarling went back and forth until in 2008 they 'reviewed' the studies and decided that, no, Stevia was safe, after all.
Which makes a person wonder if the government cares more about our safety or corporate dollars, but that's a rant for another post.
WARNING: CHEMISTRY AHEAD
The sweetness in Stevia is due to a glycoside called, originally enough, "Steviol glycoside". (Those silly chemists. When will they name something 'Fred'?) Glycosides are a big group of organic molecules that break down into a sugar and something else. For instance, cyanogenic glycosides break down into sugar and cyanide (these are the toxic chemicals in unroasted almonds and apple seeds and peach pits and the like). Get it? The steviol glycoside breaks down into glucose (the sugar) and steviol (the something else). Everyone is arguing over the safety of the steviol. I'll ease back on the chemistry, but steviol is a member of ANOTHER group of chemicals named diterpenes which are not the healthiest things in the world (diterpenes are the chemicals in coffee that make doctors tell you to cut back on it).
On the other hand, Stevia doesn't trigger the insulin whiplash that regular cane sugar does, is low-carb, and may help reduce blood pressure. So, as with so many things, I suspect the good and bad mostly balance each other out, and you should do that tiresome old grown-up thing and exercise moderation with the stuff, just like you would with 'real' sugar.
There's no such thing as a free lunch. Or a perfect sweetener.
For those who were asking, Stevia is heat-stable, meaning you can bake with it. And it doesn't ferment; I assume yeasts can't break down the glycosides to get at the sugar, and they just sit there.
On a personal note, I've used Truvia to sweeten my morning tea (my mother-in-law uses it and I just finished drinking a big whack of it while staying at her house in Ohio) and it's kinda weird. There are mentions of it in the literature. Since there has to be a chemical reaction to break down the glycoside, the actual taste of the sweetness is kind of delayed. When I use it in my tea, I swallow the tea and THEN get a zing of 'sweet' in my mouth. Not unpleasant, but kinda strange. I'm thinking I need to try this stuff in cookies and see what happens. I'll keep you posted.