Stevia rebaudiana Bertoni is a small shrub belonging to the Asteraceae family, native to South America. The leaves of the stevia plant have 30 – 45 times the sweetness of sucrose and can be eaten fresh, or put in teas and foods, as done for centuries by the Guarani people.
The glycosides that give stevia its sweet taste are stevioside and rebaudioside. The two are 250 – 300 times as sweet as sucrose and are heat-stable, pH-stable, and not fermentable.
The most abundant of these sweet molecules in the wild-type plant is stevioside, but rebaudiosideA (reb A) is widely held to be the better tasting. Stevia is widely cultivated in South America, but much of the world's commercial supply currently originates in Asia.
To commercially produce rebaudioside A, stevia plants are dried and subjected to a water extraction process. This crude extract contains about 50% rebaudioside A; its various glycoside molecules are separated via crystallization techniques, which allow isolating pure rebaudioside A.
Stevia has been the subject of biological and toxicological investigations for more than 60 years. Today, the scientific literature is awash with a large number of studies on stevia confirming its safety and benefits. In 2008, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) established a permanent Acceptable Daily Intake (ADI) for purified steviol glycosides of 4 mg/kg bodyweight/day (expressed as steviol) and validated the safety of purified steviol glycosides for use as a food and beverage sweetener. The WHO also found no evidence of carcinogenic activity, earlier claimed. Furthermore, the report noted "stevioside has shown some evidence of pharmacological effects in patients with hypertension or with diabetes mellitus type 2”.
After its approval in the United States by the Food and Drug Administration (FDA), in 2010, also the European Food Safety Authority (EFSA) concluded that steviol glycosides are safe. By 2011, European legislation was published with permitted addition rates, expressed as steviol equivalence, for defined categories of foodstuffs.
What makes Stevia the best option for dieters watching their carbohydrate or caloric intake, is the fact that it is both carb- and calorie-free. This makes it possible for them to satisfy sweet cravings without wrecking their eating plans.
Moreover, some studies has shown how Stevia helps lower blood pressure. This makes it an ideal sweetener for people with high blood pressure.
More simply, people with high blood sugar levels can take advantage from Stevia as its use will lower sugar levels. This makes it a possibly acceptable substitute for anyone with blood sugar or insulin problems, including diabetics.
The oral use of Stevia has shown antibacterial effects. These evidences have proven how Stevia can be used as an ingredient in toothpaste and mouthwashes, helping anyone fight cavities and gingivitis. Stevia has shown the same properties when used topically, and has been used in the treatment of eczema and acne.
However, for many people, the overwhelming benefit of Stevia remains the fact that it offers a healthy and natural alternative to cane sugar, corn syrup, aspartame, or saccharine.