3 Overview Stevia rebaudiana Common names include: stevia, sweet leaf, sweet herb of Paraguay, honey leaf, & sugar leafIncreasing popularity of artificial sweeteners over the past 20 yearsDemand for “natural” & “healthier” alternativesPerfect social, political, & economic climateWidespread use as a non-nutritive sweetener due to sweet leavesMuch debate over its use & health implications
4 Historical Perspective Stevia rebaudianaHistorical PerspectiveUsed extensively by native cultures of South America for centuriesFirst introduced to Europe by Spanish conquistadores in 16th centuryReintroduced in early 20th century to scientific community by Italian-Swiss botanist Dr. Moisés S. Bertoni1905 – Bertoni classified & described stevia16th century described how Paraguay’s natives used the leaves of the plant to sweeten their foods and chewed on the leaves throughout the day (The National Geographic Society 2008).
5 Historical Perspective cont. Stevia rebaudianaHistorical Perspective cont.Since 1905 – Stevia has been widely studiedThroughout 20th century sweet compounds in leaves have been isolated, purified, patented, & used in commercial products1970s – Japan began using stevia in replace of artificial sweeteners & sugarLargest consumers: Japan, South Korea, Brazil, & South AmericaNorth America and the European Union have traditionally only allowed purified extracts of S. rebaudiana to be sold in health food stores and pharmacies as dietary supplements, but recently the US Food and Drug Administration (FDA) has approved the use of highly refined stevia preparations as a sweetener in such products like soft drinks (US FDA 2011). Health Canada has recently permitted highly purified stevia extracts to be used to sweeten vitamin and mineral waters (Aquafina Plus Vitamins 10 Cal), soft drinks (Zevia), for use as a medicinal ingredient in natural health products, and for personal culinary use (Health Canada 2011).
6 Botany Stevia rebaudiana Tropical perennial & herbaceous shrub Native to Central & South AmericaMember of Asteraceae (Sunflower Family)Grows cm tallTypically found in semi-dry mountainous environments & grasslandsPrefers well-drained non-saline soil with pH
7 Botany cont. Stevia rebaudiana Simple, opposite green sessile leaves Stem, branches, & leaves are all green & are covered with short, fine whitish hairsAll green parts taste sweetInflorescences are tiny white & purple disk floretsDevelop achene fruitsCommercial cultivation of stevia began in 1964 in Paraguay, since then it has been cultivated in Brazil, Japan, China, Korea, Mexico, United States, Indonesia, Tanzania, and Canada (Madan 2010).
8 Commercial cultivation Stevia rebaudianaCommercial cultivationParaguay, Brazil, Japan, China, Korea, Mexico, USA, Indonesia, Tanzania, & Canada
9 Ethnobotany Stevia rebaudiana Guarani natives (Paraguay) credited with first using the dried leaves to sweeten yerba mate (Ilex paraguariensis) & chewed the fresh leavesNatives used orally delivered concoctions as a contraceptive, to manage diabetes, and to treat stomach achesCaá hê-é or Kaà heè, which in Guaraní, a local dialect, translates into “sweet herb”Lack of cultural & written records of steviaResearchers have postulated the following three explanations for the limited cultural record of stevia. First, the sweet-tasting properties of the plant have been known by indigenous cultures since the beginning of time and therefore were a closely guarded secret that they chose not to share with outsiders. Second, indigenous cultures shared the plant’s unique properties with the Spaniards, but the knowledge was either disregarded or overlooked by Europe at the time. Third, stevia’s potential as a sweetener was not discovered by natives until only a short time before it’s existence became known to scientists (Soejartob 2002; Lewis 1992).
10 Ethnobotany cont. Stevia rebaudiana 3 explanations for limited historical record 1. Sweet-tasting properties were known since the beginning of time, but kept a secret 2. Natives shared plant with Spaniards, but the knowledge was disregarded or overlooked 3. Stevia’s potential as a sweetener was not discovered by natives until only a short time before European contactFigure 4: Paraguayans harvest stevia.Second, indigenous cultures shared the plant’s unique properties with the Spaniards, but the knowledge was either disregarded or overlooked by Europe at the time. Third, stevia’s potential as a sweetener was not discovered by natives until only a short time before it’s existence became known to scientists (Soejartob 2002; Lewis 1992).
11 Chemistry Stevia rebaudiana Active compounds: group of diterpene (steviol) glycosidesdulcoside A, rebaudiosides A-E , steviolbioside, & steviosideRebaudioside A (3.8%) and stevioside (9.1%) are the sweetest, most abundant, & most important commerciallyHighest yield of these compounds in leaves just before the plant begins to flower,
12 Chemical structures Stevia rebaudiana Chemical structure of stevioside (left) and rebaudioside A (right)
13 Extraction & Commercial Uses Stevia rebaudianaExtraction & Commercial UsesProcessing of dried leaves from Stevia produces a powdery white substance (stevioside), which is three hundred times sweeter, by weight, than sucrose derived from sugar caneWater extraction process followed by crystallization techniques to isolate the steviol glycosidesNRC has patent on nanofiltration techniquescommercially available stevia products: stevioside and rebaudioside A include Truvia, Fructevia, Krisda, & PureVia.There are a variety of patented techniques used to extract the glycosides from the leaves that involve water extraction processes followed by crystallization techniques to isolate the steviol glycosides (Madan 2010). The National Research Council in Canada currently holds the patent on a technique that uses column extraction and purification, using nanofiltration, to isolate the desired compound (United States Patent and Trademark Office 1998). Examples of commercially available stevia products containing stevioside and rebaudioside A include Truvia, Fructevia, Krisda, and PureVia.
15 Nutrition Stevia rebaudiana The dried leaves are 30 to 45 times as sweet as sucroseNon-nutritive, three hundred times sweeter than sugar, heat stable, non-fermentable, as well as an anti-plaque and anti-carieMore studies must be conducted on bulking agents to make it easy to replace it for sugarTable from Goyal 2010,Stevia’s properties of being a natural food extract, non-nutritive, three hundred times sweeter than sugar, heat stable, non-fermentable, as well as an anti-plaque and anti-carie, has made it a popular non-caloric sweetener around the world (Goyal 2010). Another interesting characteristic of stevia is its potential to replace sugar in recipes without altering the visual acceptability and physical characteristics of the food product (Madan 2010). However, more studies must be conducted on combing stevia with various bulking agents to determine the most efficient way to substitute sugar with stevia in baked goods and confectionaries at a one-to-one ratio.Presently, Health Canada has set the acceptable daily intake guideline for steviol glycosides at 10 mg/kg(body weight)/day, which for a 75 kg person would be approximately 750 mg/day (Health Canada 2011). On average, a one-gram package of commercial stevia extract preparation contains less than a thousandth of a gram of rebaudioside A or stevioside. To illustrate the intense sweetening power of stevia, a one-gram packet of Krisda, a premium brand of stevia extract with a inulin bulking agent that is available in Canada, is equivalent to 2 teaspoons of sugar (8.4 grams) (Krisda 2011).
16 Regulation Stevia rebaudiana Traditionally, North America & EU have only permitted use of highly purified extracts for sale in health food stores & pharmaciesLeaves classified as a dietary supplement, but not as a sweetener (Health Canada 2011)FDA & Health Canada has approved use of stevia derivatives as a sweetener in some products (FDA 2011; Health Canada 2011)Marketed as medicinal, non-medicinal ingredients & for personal culinary use
17 Controversies Stevia rebaudiana Few conclusive results verifying negative health claimsInvestigated effect of stevia on energy & carbohydrate metabolism, on the cardiovascular & renal systems, & reproductionDiabetes mellitus: helps with proper blood glucose control, as antihyperglycemic by stimulating the release of insulin, & to help prevent insulin intolerance in diabetic patientsNeed for further clinical trials to ensure safety of stevia for widespread human consumptionThough indigenous cultures of Paraguay have been using stevia for centuries, its widespread use has been greatly restricted due to reports claiming that it cause harm to human health. Few studies have found conclusive results verifying this to be true, but several have investigated the effect stevia extracts have on energy and carbohydrate metabolism, on the cardiovascular and renal systems, and on reproduction (Huxtable 2002).No significant findings from these studies indicated that stevia extracts are harmful to human health (Wheeler 2008).In individuals with diabetes mellitus, stevia extracts are thought to help with proper blood glucose control, to act as antihyperglycemic by stimulating the release of insulin, and to help prevent insulin intolerance in diabetic patients (Jeppesen 2003).However, with the many controversies surrounding stevia’s use, there is clearly a need for further clinical trials to ensure extracts of S. rebaudiana are safe for human consumption.
19 References Stevia rebaudiana Goyal, S. K., Samsher, and Goyal, R.K Stevia (Stevia rebaudiana) a bio-sweetener: a review. Intl. J. Food Sci. and Nutr. 61(1): Guens, J. C Stevioside. Phytochemistry. 64(5): Health Canada Frequently Asked Questions "FAQs" on Stevia [online]. Available from [accessed 10 March 20111]. Huxtable, R. J Pharmacology and toxicology of stevioside, rebaudioside A, and steviol. In Stevia: The genus Stevia. Edited by A. Douglas Kinghorn. Taylor & Francis Inc, New York. pp Jeppesen, P. B., Gregersen, S., Rolfsen, S. E. D., Jepsen, M., Colombo, M., Agger, A., Xiaso, J., Kruh, M., and Hermansen K Antihyperglycemic and blood pressure-reducing effects of stevioside in the diabetic Goto-Kakizaki rat. Metabolism. 52: Kinghorn, A. D Overview. In Stevia: The genus Stevia. Edited by A. Douglas Kinghorn. Taylor & Francis Inc, New York. pp Krisda Canada. Product Information [online]. Available from [accessed 10 March 2011]. Lewis, W. H Early uses of Stevia rebaudiana (Asteraceae) leaves as a sweetener in Paraguay. Econ. Bot. 46: Madan, S., Ahmad, S., Singh, G. N., Kohli, K., Kumar, Y., Singh, R., and Gard, M Stevia rebaudiana (Bert.) Bertoni – A Review. Ind. J. Nat. Prod. 1(3): Rolfes, S. R., Pinna, K., and Whitney, E Understanding Normal and Clinical Nutrition (8th ed.). Wadsworth, Cengage Learning, CA, USA. pp Samuelsson, G Drugs of Natural origin. Swedish Pharmaceutical Press, Origin Stockholm Sweden. Shi Qiu, Z., Ashwani, K., and Oleh, K Membrane-based separation scheme for processing sweeteners from stevia leaves. Food Res. Int. 33: Soejartoa, D. D Botany of Stevia and Stevia rebaudiana. In Stevia: The genus Stevia. Edited by A. Douglas Kinghorn. Taylor & Francis Inc, New York. pp Soejartob, D. D Ethnobotany of Stevia and Stevia rebaudiana. In Stevia: The genus Stevia. Edited by A. Douglas Kinghorn. Taylor & Francis Inc, New York. pp Strauss, S The perfect sweetner? Technol. Rev. 98: Sumida, T Studies on Stevia rebaudiana Bertoni M, introduced from Brazil as a new sweetness resource in Japan. J. Cent. Agric. Exp. Stn. 31: The National Geographic Society Edible: An Illustrated Guide to the World’s Foods Plants. Global Book Publishing, Washington, DC. pp United States Food and Drug Administration (FDA) What refined Stevia preparations have been approved by FDA to be used as a sweetener? [online]. Available from [accessed 10 March 2011]. United States Patent and Trademark Office United States Patent: 5,972,120 Extraction of sweet compounds from Stevia rebaudiana Bertoni [online]. Available from [accessed 10 March, 2011] Wheeler, A., Boileau, A. C., Winkler, P. C., Compton, J. C., Prakash, I., Jiang, X., and Mandarino, D. A Pharmacokinetics of rebaudioside A and stevioside after single oral doses in healthy men. Food Chem. Toxi. 46: