Non-nutritive sugar substitutes are sweet tasting substances that have no food value or calories. Several non-nutritive substances found in nature are sweet. Stevia is the only natural high intensity sweetener in general use. Stevia is family of tropical herb in the sunflower family. Some of these contain a chemical know as steviol glycoside which is 300 times sweeter than sucrose. The leaves have been used for over a thousand years by indigenous people of South America. The dried leaves are about 40 times as sweet as sucrose.
The chemical structure of the steviol glycoside was discovered in 1955. It became popular in Japan in the 1970’s, and is now used across the world. In the U.S. stevia and its extracts are legal only as dietary supplements. But in 2008 Rebaudioside A (an purified isolate of stevia) became licenced as a food additive. It goes under various trade names including Truvia, SweetLeaf, NuStevia and Reb A. Other stevia extracts remain banned in the US as a food additive and are banned altogether in some European countries. This appears to be a result of political pressures from industry (the herb of course cannot be patented).
Many Stevia extracts have a bitter aftertaste. Rebaudioside A has the least bitterness of all the steviol glycosides in the stevia plant. Stevia has been shown to be safe in most studies. Several benefits have been reported that do no occur with the artificial sweeteners. It has been shown to improve insulin sensitivity in rats. And so may have some benefit in reversing diabetes and metabolic syndrome. It may also help reduce hypertension.
In my experience the herbal extracts (dietary supplements) do suffer from problems with bitterness. This depends on the brand and of course the foods being sweetened as well as personal taste. The purified stevia product, Truvia is available in stores and is definitely less bitter. I previously mentioned the stevia / erythritol blends that are available. I have used one called NuStevia No Carb Blend. It is twice as sweet as sucrose spoon for spoon and minimizes the bitterness by combining it with erythritol.
Stevia is generally considered safe. Stevia plants are available locally and can be grown outside during our summers or kept in a greenhouse over the winter.