Stevia

.Botanical Name : Stevia rebaudiana

Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Asterales
Tribe: Eupatorieae
Genus: Stevia

Family: Asteraceae

Stevia is a genus of about 150 species of herbs and shrubs in the sunflower family (Asteraceae), native to subtropical and tropical South America and Central America. The species Stevia rebaudiana Bertoni, commonly known as sweetleaf, sweet leaf, sugarleaf, or simply stevia, is widely grown for its sweet leaves. As a sugar substitute, stevia’s taste has a slower onset and longer duration than that of sugar, although some of its extracts may have a bitter or liquorice-like aftertaste at high concentrations.

With its extracts having up to 300 times the sweetness of sugar, stevia has garnered attention with the rise in demand for low-carbohydrate, low-sugar food alternatives. Stevia also has shown promise in medical research for treating such conditions as obesity and high blood pressure. Stevia has a negligible effect on blood glucose, even enhancing glucose tolerance; therefore, it is attractive as a natural sweetener to diabetics and others on carbohydrate-controlled diets.However, health and political controversies have limited stevia’s availability in many countries; for example, the United States banned it in the early 1990s unless labeled as a supplement. Stevia is widely used as a sweetener in Japan, and it is now available in the US and Canada as a dietary supplement, although not as a food additive. Rebiana is the trade name for a stevia-derived sweetener being developed jointly by The Coca-Cola Company and Cargill with the intent of marketing in several countries and gaining regulatory approval in the US and EU.

Description:Stevia rebaudiana is member of Compositae. Stevia rebaudiana is a tender perennial plant. Stem is weak and leaves are arranged alternately. Flowers are small and white and arranged in indeterminate heads. Seeds are minute.

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History and use:
For centuries, the Guaraní tribes 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 heartburn and other ailments.

In 1931, two French chemists isolated the glycosides that give stevia its sweet taste.[6] These compounds were named stevioside and rebaudioside, and are 250–300 times sweeter than sucrose (ordinary table sugar), heat stable, pH stable, and non-fermentable.

In the early 1970s, Japan 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 (including Coca Cola), and for table use. Japan currently consumes more stevia than any other country; it accounts for 40% of the sweetener market.

The Chinese American herbalist, Dr. Tei-Fu Chen, perfected a non-chemical method to extract the sweet chemicals from stevia; this method remains the primary technique used today. Dr. Chen’s company, Sunrider, processes, manufactures, and markets stevia products.

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 parts of South America (Brazil, Colombia, Peru, Paraguay, and Uruguay) and in Israel. China is the world’s largest exporter of stevioside.

Stevia 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 more effective method of reproduction.

Availability:
Stevia has been grown on an experimental basis in Ontario, Canada since 1987 for the purpose of determining the feasibility of growing the crop commercially. In the United States, it is legal to import, grow, sell, and consume stevia products if contained within or labeled for use as a dietary supplement, but not as a food additive. Stevia has also been approved as a dietary supplement in Australia, New Zealand[10] and Canada. In Japan and South American countries, stevia may also be used as a food additive. Stevia is currently banned for use in food in the European Union It is also banned in Singapore and Hong Kong.

Rebiana is the tradename for a patent-pending, calorie-free, food and beverage sweetener derived from stevia and developed jointly by The Coca-Cola Company and Cargill. In May 2007, Coca-Cola announced plans to obtain approval for its use as a food additive within the United States by 2009. Coca-Cola has also announced plans to market rebiana-sweetened products in 12 countries that allow stevia’s use as a food additive. The two companies are conducting their own studies in an effort to gain regulatory approval in the United States and the European Union.

Health controversy:
A 1985 study reported that steviol, a breakdown product from stevioside and rebaudioside (two of the sweet steviol glycosides in the stevia leaf) is a mutagen in the presence of a liver extract of pre-treated rats — but this finding has been criticized on procedural grounds that the data were mishandled in such a way that even distilled water would appear mutagenic. More recent animal tests have shown mixed results in terms of toxicology and adverse effects of stevia extract, with some tests finding steviol to be a weak mutagen while newer studies find no safety issues.

Other studies have shown stevia improves insulin sensitivity in rats and may even promote additional insulin production,[ helping to reverse diabetes and metabolic syndrome. Preliminary human studies show stevia can help reduce hypertension although another study has shown it has no effect on hypertension. Despite these more recent studies establishing the safety of stevia, government agencies have expressed concerns over toxicity, citing a lack of sufficient conclusive research.

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”. However, this statement is not backed by published scientific evidence, other than the general findings about refined foods being less beneficial.

In 2006, the World Health Organization (WHO) performed a thorough evaluation of recent experimental studies of stevioside and steviols conducted on animals and humans, and concluded that “stevioside and rebaudioside A are not genotoxic in vitro or in vivo and that the genotoxicity of steviol and some of its oxidative derivatives in vitro is not expressed in vivo.” The report also found no evidence of carcinogenic activity. Furthermore, the report noted that “stevioside has shown some evidence of pharmacological effects in patients with hypertension or with type-2 diabetes” but concluded that further study was required to determine proper dosage.

Indeed, millions of Japanese people have been using stevia for over thirty years with no reported or known harmful effects. Similarly, stevia leaves have been used for centuries in South America spanning multiple generations in ethnomedical tradition as a treatment of type II diabetes.

The FDA & Stevia

Use & Medicinal Valueof Stevia: Stevia – The Sweet Herb Stevia rebaudiana is popularly known as Sweet Herb. It is native to North Eastern Paraguay where it is used in folk medicine. Dr.Moises Santiago Bertoni (1887) reported about new species of stevia. He named Stevia rebaudiana in the honor of Paraguay chemist Rebaudi. In 1908, it was Rasenack who reported to the scientific community about presence of sweeteners in the plant. In 1931, Briedel and Lavieille continued the work of Rasenack and succeeded in isolating Stevioside.

In 1970, use of chemical sweeteners was prohibited in Japan. Stevia ahs been used as sweetener in Japan for over 25 years. It is estimated that 50 tones of Steviosides are consumed annually in Japan. Further stevia holds 50% of the sweeteners market in Japan. China is not lagging behind. Her stevia is widely used in food stuffs, beverages and pickles.

Food and Drug Administration (FDA) in late eighties banned stevia for it use as dietary supplement or sweetener. In 1991 after so much argument, FDA lifted ban on stevia and allowed the import and sale in United Stats of America. Today stevia and Steviosides are sold as dietary supplements. Experts are of the view that status of stevia as dietary supplement is appropriate and more scientific studies are required to give it status of a drug

In 1908 crop of stevia was raised for the first time. In 1918, a botanist (name not confirmed) from America introduced the people with amazing properties of the stevia. In 1932 G.S. Brady, American Trade Commissioner discussed the commercial viability of the plant. It can be said with certainty that stevia was brought in the limelight by work of Bertoni. During World War II, stevia was grown in England as a sugar substitute.

As far as traditional medicinal use of Stevia is concerned, it is has been used in Brazil and Paraguay. The Guarani community used stevia for imparting sweetness to teas.

In addition, Stevia was used for cardiac edema, obesity, high blood pressure and gastritis. Herbalists in Brazil describe stevia as hypoglycemic, antihypertensive, diuretic and cardiac tonic. They use the plant for the treatment of obesity, fatigue, dental caries and high blood pressure

Nutritional and Medicinal Uses of Stevia

The Bittersweet Story of the Stevia Herb

Guide to Using Stevia in Cooking and Natural Medicines
Stevia, The Sweet Herb

Learn More About Stevia

Stevia: The ‘Holy Grail’ of Sweeteners?

Disclaimer:
The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplements, it is always advisable to consult with your own health care provider.

Source:http://en.wikipedia.org/wiki/Stevia

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