Stevia (also called sweetleaf, sweet leaf or sugarleaf) is a genus of about 150 species of herbs and shrubs belonging to the Asteraceae (sunflower) family, native to subtropical and tropical South America and Central America (north to Mexico). The species are found in the wild in semi-arid habitats ranging from grassland to mountain terrain. Stevia does produce seeds, but only a small percentage of them germinate. Planting cloned stevia is a much more effective way of reproduction.
Uses
For centuries, the Guarani Native Americans of Paraguay and Brazil used Stevia species, primarily S. rebaudiana which they called ka’a he’ê (”sweet herb”), as a sweetener in yerba mate and medicinal teas for treating such conditions as obesity, high blood pressure, and heartburn. It has recently seen greater attention with the rise in demand for low-carbohydrate, low-sugar food alternatives, and is widely used as a sweetener in Japan, and is available in the US and Canada as a health food supplement.

In 1931, French chemists isolated the glycosides that give stevia its sweet taste. These extracts were named steviosides and rebaudiosides. These compounds are 250–300 times sweeter than sucrose (ordinary table sugar). Stevia’s sweet taste has a slower onset and longer duration than sugar’s, and especially at high concentration, it has bitter and liquorice-like off-tastes. Stevia does not significantly alter blood glucose, and so is attractive as a sweetener to diabetics and others on carbohydrate controlled diets.

In the early 1970s, the Japanese began cultivating stevia as an alternative to artificial sweeteners such as cyclamate and saccharin, suspected carcinogens. The plant’s leaves, the aqueous extract of the leaves, and purified steviosides are used as sweeteners. Stevia sweeteners have been produced commercially in Japan since 1977 and are widely used in food products, soft drinks, and for table use. Japan currently consumes more stevia than any other country; there, stevia accounts for 40% of the sweetener market.

Today, stevia is cultivated and used in food elsewhere in east Asia, including in China (since 1984), Korea, Taiwan, Thailand, and Malaysia, it can also be found in Saint Kitts and Nevis, in part of South America (Brazil, Paraguay, and Uruguay) and in Israel. China is the world’s largest exporter of the stevia extract, stevioside.

Health Concerns and Limits On Use
A European health study found that stevioside depressed the virility of male mice. It has also been reported that steviol, one of the principal metabolites of stevioside, is a mutagen. Based on these findings, the European Commission banned stevia’s use in food in the European Union pending further research. It is also banned in Singapore and Hong Kong. Additional animal tests have shown mixed results in terms of toxicology and adverse effects of stevia extract.

Stevia has been used by millions of users in modern countries such as Japan for thirty years, with no reported or known harmful effects on humans.

Whole foods proponents draw a distinction between consuming (and safety testing) only parts, such as stevia extracts and isolated compounds like stevioside, versus the whole herb. In his book Healing With Whole Foods, Paul Pitchford cautions, “Obtain only the green or brown [whole] stevia extracts or powders; avoid the clear extracts and white powders, which, highly refined and lacking essential phyto-nutrients, cause imbalance”.

In 1991, at the request of an anonymous complainant, the United States Food and Drug Administration labelled stevia as an “unsafe food additive”, and restricted its import. The FDA’s stated reason was “toxicological information on stevia is inadequate to demonstrate its safety”. This ruling was controversial, as stevia proponents pointed out this designation goes against the FDA’s guidelines, under which any natural substance used prior to 1958 with no reported adverse effects should be recognized as safe.

In 1995, the FDA revised its stance to permit stevia to be used as a dietary supplement, although not as a food additive. Currently, it is legal to import, grow, sell and consume Stevia products in the United States if it is contained within or labelled for use as a dietary supplement. You can buy Stevia products at such U.S. outlets as Whole Foods, General Nutrition Center, Trader Joe’s and other stores that carry natural foods.

Similarly, in Australia and Canada, stevia has been approved only for dietary supplements. However stevia has been grown on an experimental basis in Ontario since 1987 for the purpose of determining the feasibility of growing the crop commercially.

The first commercially developed Cola-flavored Stevia supplement was developed in 2003 by Donald Thrasher and Bill Bluemer of the Thrasher Beverage Corporation of California U.S.A. Under the brand name Z (Cola) and Z (Orange) in the U.S. and Canada, the trade name in Mexico and South America is Diet Z. ZCola.com. Besides Stevia, it also contains Erythritol as a sweetener.

This is part of a series on natural sugar substitutes. Read more here:

• Sugar Substitutes – Brazzein – Natural Sweetener
• Sugar Substitutes – Curculin – Natural Sweetener
• Sugar Substitutes – Erythritol – Natural Sweetener
• Sugar Substitutes – Fructose – Natural Sweetener
• Sugar Substitutes – Glycerol – Natural Sweeteners
• Sugar Substitutes – Glycyrrhizin – Natural Sweeteners
• Sugar Substitutes – Hydrogenated Starch Hydrolysates – Natural Sweetener
• Sugar Substitutes – Isomalt – Natural Sweetener
• Sugar Substitutes – Lactitol – Natural Sweetener
• Sugar Substitutes – Mabinlin – Natural Sweetener
• Sugar Substitutes – Maltitol – Natural Sweetener
• Sugar Substitutes – Mannitol – Natural Sweetener
• Sugar Substitutes – Miraculin – Natural Sweetener
• Sugar Substitutes – Monellin – Natural Sweetener
• Sugar Substitutes – Pentadin – Natural Sweetener
• Sugar Substitutes – Sorbitol – Natural Sweetener
• Sugar Substitutes – Stevia – Natural Sweetener
• Sugar Substitutes – Tagatose – Natural Sweetener
• Sugar Substitutes – Thaumatin – Natural Sweetener
• Sugar Substitutes – Xylitol – Natural Sweetener

Information Provided by Wikipedia