Stevia is a natural sweetener and sugar substitute derived from the leaves of the plant species Stevia rebaudiana, native to Paraguay and Brazil.
The active compounds are steviol glycosides which have about 50 to 300 times the sweetness of sugar, are heat-stable, pH-stable, and not fermentable.
The human body does not metabolize the glycosides in stevia, so it contains zero calories as a non-nutritive sweetener.
Stevia’s taste has a slower onset and longer duration than that of sugar.
At high concentrations, stevia, it may have an aftertaste described as licorice-like or bitter.
Stevia is used in sugar- and calorie-reduced food and beverage products as an alternative for variants with sugar.
High-purity stevia glycoside extracts have been generally recognized as safe (GRAS) and may be lawfully marketed and added to food products, but stevia leaf and crude extracts do not have GRAS or Food and Drug Administration (FDA) approval for use in food.
Steviol, is the basic building block of stevia’s sweet glycosides.
Glycosides are molecules that contain glucose residues bound to other non-sugar substances called aglycones, while molecules with other sugars are polysaccharides.
The tongue’s taste receptors react to the glycosides and transduce the sweet taste sensation and the lingering bitter aftertaste by direct activation of sweet and bitter receptors.
Steviol glycosides and steviol interact with a protein channel potentiating the signal from the sweet or bitter receptors, amplifying the taste of other sweet, bitter and umami tastants.
The synergetic effect of the glycosides on the sweet receptor explains the sweetness sensation.
Steviol is processed by intestinal microflora and is also taken up into the bloodstream.
Steviol is metabolized by the liver to steviol glucuronide and several other metabolites, and excreted in the urine.
A review found that the use of Stevia sweeteners as replacements for sugar might benefit children, people with diabetes, and those wishing to lower their intake of calories.
Mutagenic effects have not been demonstrated for the doses and routes of administration to which humans are exposed.
The acceptable daily intake of steviol glycoside of up to 4 mg/kg of body weight.
A Memorial Sloan Kettering Cancer Center warns that steviol at high dosages may have weak mutagenic activity.