Stevia
Stevia rebaudiana

Location
Stevia can be found in the Wildflower plot.

Description
Native to high altitude regions of Paraguay and Brazil, Stevia grows well in warm climates and is cultivated in Brazil, Israel, Japan, Korea, and China (Fugh-Berman 2003).

History
Called “sweet herb” in Paraguay, Stevia rebaudiana is reported to be the sweetest of the nearly 200 species of stevia that grow in the Central and South American region (Duke 2000). Used as a sugar substitute, herbalists recommend stevia to help prevent tooth decay by replacing other cavity-causing sweeteners (Duke 1997).

Current medicinal uses
A popular sweetener, the dried leaf is 250 times sweeter than sugar. Rebaudioside A (reb A), a glycoside found in the leaves of Stevia rebaudiana, was recently approved for use by the Food and Drug Administration (Associated Press 2008). Research into the safety of reb A indicates that chronic consumption of 1000 mg has no clinical effect on blood pressure or blood sugar in healthy patients or those with type 2 diabetes mellitus (Barriocanal 2008, Maki 2008).

Stevioside, another glycoside isolated from Stevia rebaudiana, has potential as a treatment for type 2 diabetes. In one study, 12 patients with type 2 diabetes mellitus were given a meal supplemented with either 1 g of stevioside or 1 g of a maize starch control and their blood glucose levels were monitored. Stevioside significantly reduced the blood glucose response in the treatment group, suggesting that further research into its effectiveness in treatment of diabetes is warranted (Gregersen 2004). Research also indicates the anti-hypertensive potential of stevia extract. A clinical trial of 106 hypertensive patients found that oral stevioside lowered blood pressure more than placebo (Chan 2000). As stevioside has been used as a commercial sweetener in Japan for over 20 years, it is likely a safe supplement for those suffering from hypertension or diabetes.

Adverse effects
No serious adverse events have been reported, although limited research suggests that stevia may have mild contraceptive effects, so women trying to get pregnant should watch their stevia intake (Duke 2000).

References
Associated Press. “FDA approves 2 new sweeteners.” The New York Times. 17 Dec 2008. http://www.nytimes.com/2008/12/18/business/18sweet.html.

Barriocanal LA et al. Apparent lack of pharmacological effect of steviol glycosides used as sweeteners in humans. A pilot study of repeated exposures in some normotensive and hypotensive individuals and in Type 1 and Type 2 diabetics. Regul Toxicol Pharmacol. 2008; 51(1): 37-41.

Chan P et al. A double-blind placebo-controlled study of the effectiveness and tolerability of oral stevioside in human hypertension. Br J Clin Pharmacol. 2000; 50: 215-220.

Duke JA. The Green Pharmacy. St. Martin’s Press, 1997.

Duke JA. The Green Pharmacy Herbal Handbook: Your Comprehensive Reference to the Best Herbs for Healing. Rodale Inc. 2000.

Fugh-Berman A. The 5-Minute Herb and Dietary Supplement Consult. Lippincott, Williams, and Wilkins, Baltimore, 2003: 298-299.

Gregersen S et al. Antihyperglycemic effects of stevioside in type 2 diabetic subjects. Metabolism. 2004; 53(1): 73-6.

Maki KC et al. The hemodynamic effects of rebaudioside A in healthy adults with normal and low-normal blood pressure. Food Chem Toxicol. 2008; 46 Suppl 7: S40-6.

Maki KC et al. Chronic consumption of rebaudioside A, a steviol glycoside, in men and women with type 2 diabetes mellitus. Food Chem Toxicol. 2008; 46 Suppl 7: S47-53.