Stevioside is a compound found in high concentration in the Stevia rebaudiana (Bertoni) plant and is responsible for the sweet taste of the leaves. This compound is now being used commercially to sweeten a variety of products and for medicinal purposes. The Stevia genus and its major constituent stevioside have undergone major reviews and are now generally regarded as safe.
Oral Toxicity Studies
Studies in mice, rats and hamsters indicated that stevioside bears a very low acute oral toxicity. Several groups of researchers demonstrated the safety of oral stevioside in terms of carcinogenic activity using rat studies. In 2004, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) requested more information be submitted on the effects of stevia in humans. Since then, several studies have been performed, including a study showing that consumption of as much as 1,000 mg/day of rebaudioside A, one compound responsible for the sweetness of stevia, did not affect blood pressure in healthy adults.
Fertility and Reproduction Studies
Numerous studies on fertility or reproduction in mice, rats and hamsters led to the conclusion that stevioside does not have any significant effect on spermatogenesis, or sperm cell formation, or on tumor formation in the testes when fed rations containing up to 1 percent stevioside for 22 months. Other studies, however, demonstrated that steviol, the compound resulting from the breakdown of stevioside, is toxic to pregnant hamsters and their fetuses when given doses of 0.5 to 1.0 g/kg body weight/day on day 6 through 10 of gestation. In humans, however, the Food and Drug Administration (FDA) has determined that consumption within the daily acceptable intake during pregnancy does not constitute a health hazard.
WHO Evaluation
In an evaluation of the experimental studies of stevia extract in animals and humans in 2006, the World Health Organization (WHO) concluded that the compounds responsible for the sweet taste of stevia are not toxic based on studies both in cells and in the human body. They concluded that no evidence existed to demonstrate carcinogenic activity of stevia but also recommended further investigation to determine proper dosage.
FDA Evaluation
In 2008, the FDA responded to a Substances Generally Recognized as Safe (GRAS) notice, which is designed to inform the FDA of the safety of various substances, from the Whole Earth Sweetener Company, a producer of stevia extracts. The notice established the safety of rebaudioside A, responsible for the sweet taste of stevia, as a sweetener in a variety of foods, such as cereals, fruit juice drinks and flavored waters, based on the scientific evidence provided. The FDA also agreed with the acceptability of its use as a tabletop sweetener based on Whole Earth's recommendation.
References
- Food and Drug Administration: Agency Response Letter GRAS Notice No. GRN 000252
- Archives Pharmacology Chemical Life Science: Stevioside and Related Compounds -- Molecules of Pharmaceutical Promise: A Critical Overview. Brahmachari G, Mandal LC, Roy R, Mondal S, Brahmachari AK. 2010, 000, 1--15
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