The stevia herb provides a calorie-free sweetener that does not raise blood sugar levels in those who consume it (see Resource 3 below). Stevioside, a glucoside extracted from the herb, is up to 300 times sweeter than ordinary table sugar, and it is sold in concentrated form as a substitution for sugar and other artificial sweeteners. Stevia rebaudiana is the specific species grown as a crop and in home gardens for a natural substitute to sugar.
Stevia rebaudiana, which is one of 150 species of stevia, is a member of the Asteraceae family and is a relative of daisies and chrysanthemums (see Reference 3 below). This perennial herb reaches a height of 24 in. in its native of South America, and small white flowers decorate its foliage in late summer (see Resource 1 below). Stevia rebaudiana's leaves contain stevioside and rebaudioside A, which are glycosides that contribute to stevia's naturally sweet taste.
The history of stevia use traces back to the Paraguayans who used it as a sweetener in yerba maté tea. Dr. Moises Santiago Bertoni learned of this plant in 1887 and set out to discover the species during his study of herbs. He named stevia rebaudiana after the Paraguayan chemist who successfully extracted the plant's sweet-tasting component (see Reference 1 below). French chemists identified stevioside in 1931. Stevia then became a crop plant in other countries, according to Dr. T. Ombrello of the Union County College Biology Department. Although Japan has used it as a sweetener since the 1970s (see Reference 1 below), the Food and Drug Administration did not approve of its use in the U.S. until 2008.
Stevia has both culinary and medicinal uses. The leaves and extracts of stevia rebaudiana sweeten beverages, and the liquid or powdered extracts serve as substitutes for ordinary table sugar in some recipes. Clinical trials show that stevioside may reduce blood pressure in people with hypertension and that it may reduce blood glucose levels for diabetics, according to Georgetown University Medical Center (see Reference 2 below). Mayo Clinic nutritionist Katherine Zeratsky recommends that people with hypo-tension or hypoglycemia use stevia with caution and that women avoid it if pregnant or breastfeeding (see Resource 3 below).
People chew fresh stevia leaves for refreshment and use dried leaves for culinary purposes. The liquid extract and powdered forms of stevia are sold in health stores and some supermarkets as a dietary supplement. Now that the FDA has approved its use as a sweetener, consumers can purchase the powdered form in packets, though some brands blend the stevia with other sweeteners.
Gardeners in warmer climates can grow their own stevia rebaudiana plants. Ombrello notes that it requires no more care than a typical houseplant and that it can thrive as a potted plant in a sunny windowsill (see Reference 3 below). Stevia.net advises against growing stevia from seed because germination is difficult and the stevioside levels may vary too much between plants (see Resource 2 below). Contact your local nursery for information on planting or ordering stevia starter plants.