Stevia rebaudiana is a South American plant of the Asteraceae family, which also includes sunflowers and chrysanthemums.
Native to Paraguay, stevia has traditionally been used to sweeten beverages and make tea. The term "stevia" refers to the entire plant and its components, only some of which are sweet.1
While the word "stevia" refers to the entire plant, for the purposes of this article, the term "stevia" will be used interchangeably to also refer to "steviol glycosides" - the sweet components isolated and purified from the stevia leaves.
This article looks at what stevia is, how it is extracted, its health benefits, how it is used, whether it is safe and its current regulatory status. You will also see introductions at the end of some sections to any recent developments that have been covered by MNT's news stories. Also look out for links to information about related conditions.
Fast facts on stevia
Here are some key points about stevia. More detail and supporting information is in the main article.
- Stevia is a plant naturally grown in Brazil and Paraguay.
- Stevia is much sweeter than sugar - the extract can taste 250-300 times sweeter than table sugar.
- The extract is contained in a number of food items in the US such as energy bars, candies, protein drinks and some teas.
- Since stevia is so much sweeter than sugar, recipes require less of it.
- Stevia does not brown and caramelize the same way sugar does.
- Stevia is calorie-free, but that does not necessarily mean you will lose weight if you swap sugar for stevia.
- The stevia leaves contain potassium, zinc, magnesium and vitamin B3.
- Based on the stevia nutrition facts, it is the 10.77% fiber which helps in curing constipation and promotes proper digestion.
- One of the benefits of stevia is that it contains a 702 ppm level of iron which can stimulate the production of hemoglobin.
- Stevia and other artificial sweeteners that have been approved for use in the US do not appear to pose any health risks when used in moderation.
What is stevia?
Stevia plants grow and are harvested in many countries around the world, predominantly in China and Brazil. The plants grow 2-4 feet in height with slim, branched stems, and thrive in temperate and some tropical regions. Stevia is grown by natural, conventional plant breeding methods such as cross-pollination and other non-genetically modified processes.
Stevia is an intensely sweet natural sweetener that is harvested around the world from the stevia rebaudiana plant.
The plant is cultivated as a commercial crop in Japan, China, Kenya, Vietnam, India, Argentina, Colombia, Thailand, Paraguay, and Brazil. Currently, China is the leading exporter of stevia products.8,19
Stevia provides an important role in biodiversity due to how little land is required to grow it, allowing farmers to diversify their crops. Unlike commodity crops, stevia is grown on smaller plots of land and provides supplemental income to more commonplace crops.
As stevia is intensely sweet and an extract, it typically requires only a fifth of the land and much less water to provide the same amount of sweetness as other mainstream sweeteners. For example, in Kenya, stevia is typically grown on only a third of the land, with the rest of the land being devoted to other crops.
In a 2013 study, the carbon footprint of stevia was shown to be 79% lower than high fructose corn syrup (HFCS), 55% lower than beet sugar, and 29% lower than cane sugar, based on industry production standards.
There are 150 species of stevia, all native to South and North America. The sweetness of the stevia leaves is caused by eight glycosides contained within them. These glycosides are stevioside, rebaudioside A, C, D, E and F, steviolbioside, and dulcoside A. Stevioside is the most abundant of these components; the leaves of some cultures contain up to 18% stevioside.
Although it was not until the 19th century that scientists began seriously investigating stevia, the indigenous people of Paraguay were using the plant as early as the 16th century to sweeten drinks and medicines.
During his studies of herbs used as sweeteners by native people, Dr Moises Santiago Bertoni, a Swiss botanist of Italian descent, is credited with having notified the world of stevia's existence.
French chemists identified stevioside in 1931 and its use expanded. In the 1950s, Japan began growing the stevia plant as a crop.
Countries with a history of using stevioside as a no calorie sweetener include Japan, China, South Korea, Taiwan, Israel, Brazil, Uruguay, Paraguay, Columbia, Thailand, Germany and Malaysia.
Some of the common and trade names for stevia sweeteners are Enliten, PureVia, Rebaudioside A/Reb A, Rebaudioside B, Rebaudioside C, Rebaudioside D, Rebiana, Stevia, Steviacane, Steviol Glycosides, Stevioside, Stevia Extract In The Raw, and SweetLeaf.
Health benefits of stevia
Steviol glycosides have zero calories. Stevia-based tabletop sweeteners can have zero or minimal calories per serving, depending upon the other food ingredients with which they are combined. These factors could have a positive effect on those looking to control weight or manage diabetes.
Stevia also contains certain vitamins (A, B, C), minerals (iron, zinc, calcium), electrolytes (sodium, potassium), proteins, and other elements.21
Below, we take a look at the possible health benefits of stevia.8
Research indicates that stevia sweeteners do not contribute calories or carbohydrates to the diet and do not affect blood glucose or insulin response.
Research has shown that stevia sweeteners do not contribute calories or carbohydrates to the diet and do not affect blood glucose or insulin response, which allows people with diabetes to consume a wider variety of foods and comply with a healthful meal plan.
A randomized controlled trial over 16 weeks had 122 participants take four doses of approximately 330 mg of steviol equivalents over the course of a day. Compared to placebo, there was no impact on blood sugar levels. For this study, >97% rebaudioside A was used.
Additionally, a position paper on nutritive and non-nutritive sweeteners from the Academy of Nutrition and Dietetics reviewed five randomized controlled trials examining the effects of stevia compared with placebos on metabolic outcomes.
The studies reported minimal to no effects on blood glucose, insulin levels, hypertension and body weight. In one study showing minimal effects, subjects with type 2 diabetes reported reduced postprandial blood glucose and glucagon response after a test meal of stevia versus placebo.
2) Weight control
The causes of overweight and obesity around the globe are quite complex and include factors such as an increase in physical inactivity due to increased sedentary time and increased intake of energy-dense foods that are high in fat and added sugars.
The intake of added sugars has been shown to contribute an average of 16% of the total calories in the American diet, and has been linked to weight gain and adverse effects on glycemic control.11
Plant-based, zero calorie stevia can be part of a well-balanced diet to help reduce energy intake without sacrificing taste.
Replacing just 25g (about 6 teaspoons) of nutritive sweeteners in foods and beverages can provide a 100-kilocalorie reduction.
Steviol glycosides are poorly absorbed in the body and pass through the upper gastrointestinal tract, including the stomach and small intestines, fully intact.
Once steviol glycosides reach the colon, gut bacteria hydrolyze steviol glycosides into steviol by snipping off their glucose units. Steviol is then absorbed via the portal vein and primarily metabolized by the liver, forming steviol glucuronide, before being excreted in the urine.
Research has shown that there is no accumulation of stevia (or any byproduct of stevia) in the body during metabolism. It is a result of this essentially poor absorption in the digestive tract which ultimately contributes to the fact that stevia has zero calories and does not raise blood glucose or insulin levels when digested.
4) Pancreatic cancer
Stevia plant has many sterols and antioxidant compounds like triterpenes, flavonoids, and tannins. Some of flavonoid polyphenolic anti-oxidant phytochemicals present in stevia are kaempferol, quercetin, chlorogenic acid, caffeic acid, isoquercitrin, and isosteviol. Studies have found that kaempferol can reduce the risk of pancreatic cancer by 23% (American Journal of Epidemiology).
5) Blood pressure
Certain glycosides in stevia extract have been found to dilate blood vessels, increase sodium excretion, and urine output. In effect at slightly higher doses than as a sweetener, stevia can potentially help lower blood pressure.
The plant may have cardiotonic actions, which normalize blood pressure and regulate heartbeat. The plant displayed vasodilatory actions in both normotensive and hypertensive animals.
6) Special populations
Regulatory health agencies around the world have approved high purity stevia leaf extract for safe use. This includes special populations such as pregnant and nursing women, children and people with allergies or diabetes.
Foods and beverages containing stevia can play an important role in decreasing calories from unwanted sweeteners in children's diets. There are now thousands of products containing naturally-sourced stevia on the market, ranging from salad dressing to snack bars, that allow children to consume foods and beverages that taste great without added calories.
Multiple global regulatory organizations, including the Food and Agriculture Organization of the UN (FAO) and World Health Organization's (WHO) Joint Expert Committee on Food Additives (JECFA), European Food Safety Authority (EFSA), and the Food & Drug Administration (FDA) have determined that high purity stevia extract is safe for consumption by the general population including children, when consumed within the recommended levels.
In 2010, the EFSA reviewed literature to determine if there was any cause for concern regarding the potential for allergenicity of the stevia plant. The reviewers concluded that "steviol glycosides are not reactive and are not metabolized to reactive compounds, therefore, it is unlikely that the steviol glycosides under evaluation should cause by themselves allergic reactions when consumed in foods."
Additionally, while there is no scientific reason to suggest genetically modified crops or "GMOs" cause allergies, it is worth pointing out that stevia plants are not genetically modified, and therefore there should be no concerns regarding potential for allergenicity.
Stevia extract has exhibited strong bactericidal activity against a wide range of pathogenic bacteria, including certain Escherichia coli strains. Steviol was observed to be mutagenic toward Salmonella and other bacterial strains under various conditions and toward certain cell lines.
Stevia may also be effective against Candida albicans and has shown some anti rotavirus activity. Stevioside has shown promising immunomodulating effects in rats and cell lines. In addition, stevia may have antiproliferative/antimutagenic/antioxidant properties. One report addresses stevia's role in reducing dental plaque.
On the next page we look at how stevia is extracted and how it is used. On the final page we discuss how safe stevia is.