Can you imagine a sugar that is actually healthy and not containing any calories? That’s what they say stevia is, a healthy alternative to sucrose or other artificial sweeteners such as saccharin. But is it as healthy and non-artificial as it has been reported to be in the media? Find in this blog post everything you need to understand stevia!
Stevia rebaudiana is a small perennial growing up to 65−80 cm tall, with sessile, oppositely arranged leaves. Different species of Stevia contain several potential sweetening compounds, with S. rebaudiana being the sweetest of all. This plant was first brought to the attention of the rest of the world by the botanist Moises Santiago Bertoni in 1887, who learned of its properties from the Paraguayan Indians. The chemical characterization of the natural constituents of the plant known as steviol glycosides, which are responsible for its distinct sweet taste, was not identified until 1931 when stevioside, a primary steviol glycoside, was first isolated from stevia leaves.
But how these renowned plant-based glycosides got into our dishes? According to literature, Japan was the first country to commercialize and use crude, unpurified extracts of S. rebaudiana in the 1970s on a large scale. Its use eventually spread to several countries in Asia and Latin America. But when stevia made it into the US as a dietary supplement in health food stores, it was reported to have a liquorice flavour with a sweet or bitter aftertaste, limiting their widespread commercial development. This was due to the presence of essential oils, tannins, and flavonoids in the crude extracts. In consequence, the food industry made efforts to purify extracts and chemically characterize steviol glycosides.
After the isolation of stevioside, several other steviol glycosides, such as rebaudiosides (Reb) A, B, C, D, and E and dulcoside A, were identified and isolated from stevia leaves. Generally, the most abundant steviol glycosides in stevia leaves are stevioside (4–13%), Reb A (2–4%), and Reb C (1–2%).
At present, high-purity steviol glycosides are approved as sweeteners by all major regulatory authorities across the globe, and >150 countries have approved or adopted its use in foods and beverages. Reb A was the first commercial steviol glycoside launched in the marketplace.
But are our guts actually capable of degrading these highly-purified stevia compounds? It seems they are! The absorption, metabolism, and excretion of steviol glycosides have been extensively reviewed by multiple scientific authorities and experts, including the European Food Safety Authority (EFSA). Steviol glycosides are undigested in the upper gastrointestinal tract. They are hydrolyzed or degraded only when they come into contact with microbiota in the colon that cleave the glycosidic linkages, removing the sugar moieties, leaving behind the steviol backbone that is absorbed systemically, glucuronidated in the liver, and excreted via urine in humans.
The safety of steviol glycosides from numerous toxicological, biological, and clinical studies has been reviewed in several publications, and in fact, all major global scientific and regulatory bodies have determined high-purity steviol glycosides to be safe for consumption by
the general population.
It is well-known that several global and country-level authoritative dietary guidelines recommend a reduction in added-sugar intake due to the growing prevalence of overweight, obesity, and diabetes around the world. These guidelines include recommendations to keep added-sugar intake to <10% of total calorie intake, and as low as 5% for additional health benefits. Consequently, the replacement of caloric sweeteners in foods and beverages with high-purity stevia leaf extract sweeteners (i.e., steviol glycosides) is a useful and cost-effective tool in reducing added sugar intake.