The legal status of stevia extracts as food additives and supplements varies from country to country. In Japan, for example, stevia has been widely used for decades as a sweetener. In some other countries, health concerns and political controversies have led to various restrictions, or outright prohibition. The United States, for example, banned stevia in the early 1990s and only approved some specific glycoside extracts for use as food additives in 2008. The European Union only approved stevia additives in 2011.
The plant Stevia rebaudiana has been used for more than 1,500 years by the Guaraní peoples of South America, who called it ka'a he'ê ("sweet herb"). The leaves have been traditionally used for hundreds of years in both Brazil and Paraguay to sweeten local teas and medicines, and as a "sweet treat". The genus was named for Spanish botanist and physician Petrus Jacobus Stevus (Pedro Jaime Esteve 1500–1556) a professor of botany at the University of Valencia.
In 1899 Swiss botanist Moisés Santiago Bertoni, while conducting research in eastern Paraguay, first described the plant and the sweet taste in detail. Only limited research was conducted on the topic until in 1931 two French chemists isolated the glycosides that give stevia its sweet taste.
In the early 1970s, sweeteners such as cyclamate and saccharin were suspected of being carcinogens. Consequently, Japan began cultivating stevia as an alternative. The plant's leaves, as well as the aqueous extract of the leaves and purified steviosides, were developed as sweeteners.
The first commercial stevia sweetener in Japan was produced by the Japanese firm Morita Kagaku Kogyo Co., Ltd. in 1971. The Japanese have been using stevia in food products and soft drinks, (including Coca Cola), and for table use. Japan currently consumes more stevia than any other country, with stevia accounting for 40% of the sweetener market.
In the mid 1980s, stevia began to become popular in U.S. natural foods and health food industries, as a non-caloric natural sweetener for teas and weight-loss blends. The makers of the synthetic sweetener NutraSweet asked the FDA to require testing of the herb.
In 2007 The Coca-Cola Company announced plans to obtain approval for their stevia-derived sweetener, Rebiana, for use as a food additive within the United States by 2009, as well as plans to market Rebiana-sweetened products in 12 countries that allow stevia's use as a food additive.
In May 2008 Coca Cola and Cargill announced the availability of Truvia, a consumer brand stevia sweetener containing erythritol and Rebiana, which the FDA permitted as a food additive in December 2008. Coca-Cola announced intentions to release stevia-sweetened beverages in late December 2008.
Shortly afterward, PepsiCo and Pure Circle announced PureVia, their brand of stevia-based sweetener, but withheld release of beverages sweetened with rebaudioside A until receipt of FDA confirmation. Since the FDA permitted Truvia and PureVia, both Coca Cola and PepsiCo have introduced products that contain their new sweeteners.
As of 2006, China was the world's largest exporter of stevioside products.
Industrial extracts and derivatives
Stevia extracts and derivatives are produced industrially by many companies, and marketed under many trade names. Some of them are
Erylite Stevia: trade name for Jungbunzlauer's sweetener with rebaudioside A.
Mechanism of action
Glycosides are molecules that contain glucose and other non-sugar substances called aglycones (molecules with other sugars are polysaccharides). The tongue's taste receptors react to the glucose in the glycosides: those with more glucose (rebaudioside) taste sweeter than those with less (stevioside). Some of the tongue's bitter receptors react to the aglycones.
In the digestive tract, rebaudiosides are metabolised into stevioside. Then stevioside is broken down into glucose and steviol. The glucose released in this process is used by bacteria in the colon and not absorbed into the bloodstream. Steviol cannot be further digested and is excreted.
Potential health effects
A 2009 review summarized the basic research in which steviosides and related compounds are being tested for possible anti-disease actions, with no effect yet demonstrated in humans. A 2011 review found that the use of stevia sweeteners as replacements for sugar might benefit diabetic patients because it is a non-caloric additive.
Safety and regulations
Steviol and rebaudioside A are not mutagenic at doses and routes of administration at which humans are exposed to them. Two 2010 review studies found no health concerns with stevia or its sweetening extracts.
The plant may be grown legally in most countries, although some countries restrict its use as a sweetener. The legally allowed uses and maximum dosage of the extracts and derived products vary widely from country to country.
Stevia tablets as widely sold in health food stores in Germany
Argentina: available as of 2008, regulatory status uncertain.
Stevia rebaudiana leaf and extracts are available as dietary supplements since 1995, but the 2008 FDA authorization does not extend to them, and they do not have GRAS status.
Vietnam: available as of 2008, regulatory status uncertain.
Rebaudioside A has the least bitterness of all the steviol glycosides in the Stevia rebaudiana plant. To produce rebaudioside A commercially, stevia plants are dried and subjected to a water extraction process. This crude extract contains about 50% rebaudioside A. The various glycosides are separated and purified via crystallization techniques, typically using ethanol or methanol as solvent.
The National Research Council of Canada has patented a process for extracting sweet compounds from stevia by column extraction at temperatures from 0 to 25 °C, followed by purification by nanofiltration. A microfiltration pretreatment step is used to clarify the extract. Purification is by ultrafiltration followed by nanofiltration.
In 1991, after receiving an anonymous industry complaint, the United States Food and Drug Administration (FDA) labeled 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."
Since the import ban in 1991, marketers and consumers of stevia have shared a belief that the FDA acted in response to industry pressure.Arizona congressman Jon Kyl, for example, called the FDA action against stevia "a restraint of trade to benefit the artificial sweetener industry". To protect the complainant, the FDA deleted names in the original complaint in its responses to requests filed under the Freedom of Information Act.
Stevia remained banned until after the Dietary Supplement Health and Education Act of 1994 forced the FDA in 1995 to revise its stance to permit stevia to be used as a dietary supplement, although not as a food additive – a position that stevia proponents regarded as contradictory because it simultaneously labeled stevia as safe and unsafe, depending on how it was sold.
Early studies prompted the European Commission in 1999 to ban stevia's use in food in the European Union pending further research. In 2006, research data compiled in the safety evaluation released by the World Health Organization found no adverse effects. Since 2008, the Russian Federation has allowed stevioside as a food additive "in the minimal dosage required".
In December 2008, the FDA gave a "no objection" approval for GRAS status to Truvia (developed by Cargill and The Coca-Cola Company) and PureVia (developed by PepsiCo and the Whole Earth Sweetener Company, a subsidiary of Merisant), both of which use rebaudioside A derived from the Stevia plant. However, FDA said that these products are not Stevia, but a highly purified product. In 2012, FDA posted a note on their website regarding crude Stevia plant: "FDA has not permitted the use of whole-leaf Stevia or crude Stevia extracts because these substances have not been approved for use as a food additive. FDA does not consider their use in food to be GRAS in light of reports in the literature that raise concerns about the use of these substances. Among these concerns are control of blood sugar and effects on the reproductive, cardiovascular, and renal systems."
Thaumatin, a natural sweetener, derived from an African fruit
Miraculin, a substance that modifies the perception of sour foods into sweet.
^"Stevia". Merriam-webster.com. 31 August 2012. Retrieved 13 February 2013.
^"Stevia". British & World English. Oxforddictionaries.com. 7 February 2013. Retrieved 13 February 2013.
^"Stevia". US English. Oxforddictionaries.com. 7 February 2013. Retrieved 13 February 2013.
^Both /ˈstiːvɪə/ and /ˈstɛvɪə/ are recorded by at least some US and UK dictionaries, but the former is more common in US English (listed first or exclusively) and the latter is more common in UK English.
^Koyama, E., et al. "In vitro metabolism of the glycosidic sweeteners, stevia mixture and enzymatically modified stevia in human intestinal microflora." Food and Chemical Toxicology 41.3 (2003) 359–374.
^Ulbricht, C.; Isaac, R.; Milkin, T.; Poole, E. A.; Rusie, E. et al. (April 2010). "An evidence-based systematic review of stevia by the Natural Standard Research Collaboration". Cardiovasc Hematol Agents Med Chem8 (2): 113–27. PMID20370653.
^"Commission Regulation (EU) No 1131/2011" (PDF). Official Journal of the European Union: 7. 11 November 2011. Retrieved 15 November 2011. The CE regulation establishes steviol glycosides as food additive, and establishes maximum content levels in foodstuff and beverages.