Since ancient times, the South American native plant stevia has been used as a sweetener. Zero-calorie stevia, in the form of high-purity stevia leaf extract, is now utilized on a global scale to lessen the number of calories and added sugar in meals and beverages. In this introduction to stevia, we’ll cover its sustainable manufacturing, how it works in the body, how safe it is, and how it may be used in foods and beverages to help people consume less energy. The data supporting the contribution of nonnutritive sweeteners to energy reduction is also summarized in the article. Overall, stevia looks promising as a novel strategy for aiding in weight loss.
WHAT NATIONALITY IS STEVIA?
For hundreds of years, people have used stevia, a naturally occurring, calorie-free sweetener, as a natural sugar substitute and flavoring agent. The stevia plant is indigenous to South America, where it was initially consumed more than 200 years ago by locals who chewed the leaves for their sweetness or used them to sweeten drinks. The dried plant leaves, sometimes known as “sweet herb,” were consumed as a pleasant treat or used to sweeten beverages and medications.
In Paraguay, Moises Santiago de Bertoni identified the stevia plant for the first time as Eupatorium rebaudianum in 1899. It was later identified as Stevia rebaudiana, a sunflower (Asteraceae) family member, in 1905.
Stevia was originally used commercially as a sweetener in Japan in the 1970s, and it is still a well-liked component there today. Most countries in the world, including Vietnam, Brazil, India, Argentina, and Colombia, as well as Kenya, China, and the United States, farm stevia.
Definitions of stevia
The general term “stevia” is used to describe to several types of sweetener, including the entire Stevia plant (S rebaudiana Bertoni) and the leaves that contain the sweet chemicals. The term “stevia extract” refers to a preparation that is created by steeping Stevia plant leaves to draw out the plant’s sweet-tasting components.
On the other hand, steviol glycosides make up at least 95% of high-purity stevia leaf extract. Major regulatory bodies, such as the Joint Food and Agriculture Organization/World Health Organization (WHO) Expert Committee on Food Additives and Codex Alimentarius (Codex), have only approved high-purity stevia extracts satisfying this criterion for use in foods and beverages.
High-purity stevia leaf extract is referred to as “earthomaya stevia” in this article.
Since more than 200 years ago, people have been using the natural plant extract stevia as a sweetener. But today’s market has high-purity stevia leaf extract.
Steviol glycosides are the naturally occurring substances in the stevia leaf that give stevia its sweet flavor. Rebaudioside A and stevioside are the two most prevalent of the 11 primary steviol glycosides
- The fundamental chemical makeup of all steviol glycosides is depicted in Figure 22. One or more steviol glycosides, which can be up to 250–300 times sweeter than sucrose, may be present in purified stevia leaf extracts.
PRODUCTION OF STEVIA
Steviol glycosides are extracted from the stevia leaf using a procedure depicted, along with their filtration and purification.
2. Comparable to how other plant-based components, like cane sugar or natural vanilla extract, are created through a series of procedures starting with the harvested, raw plant material and ending with the finished product, the process of purifying stevia into high-purity stevia leaf extract is similar. The procedure starts with the leaves being dried before they are steeped in hot water. Next, water is used to filter and purify the liquid extract, often in conjunction with food-grade alcohol. If food-grade alcohol is used, it is subsequently eliminated, leaving virtually no alcohol in the finished product. Occasionally, different procedures might be applied. The cited article by Prakash et al. has additional technical information.
3. The original leaf-found compounds, known as steviol glycosides, are present in the purified form. To satisfy US and European regulatory approvals and safety standards for usage in foods and beverages, high-purity stevia leaf extracts (>95 percent steviol glycosides) are needed.
In comparison to other natural sweeteners, stevia uses less energy, water, and land to create the same sweetness. According to a carbon and water footprint analysis from one of the biggest stevia manufacturers, which used sweetness equivalence as a benchmark, stevia has an 82 percent lower carbon footprint than beet sugar and a 64 percent lower carbon footprint than cane sugar. Stevia had a 95 percent lower water footprint than cane sugar and a 92 percent lower water impact than beet sugar. The Publicly Available Standard 2050 (PAS 2050), the most widely used approach for product lifecycle analysis of carbon emissions that contribute to greenhouse gases, was used to determine the carbon footprint. This method included all direct emissions from operations and the transportation of goods, emissions from purchased electricity, and emissions from sources not owned or controlled by the company, but only directly related to the supply chain. It also included embedded carbon in the agricultural inputs and ingredients used in the processes. The Water Footprint Network’s Water Footprint Assessment Methodology was used to calculate the water footprint, which included the irrigation and process water used to grow stevia.
Additionally, stevia is giving farmers in nations like Kenya, Paraguay, and Brazil the chance to develop lucrative crops that advance public health objectives.
EXTRACT OF PURIFIED STEVIA LEAF
High-purity stevia extract, also known as stevia, steviol glycosides, stevia extracts, purified stevia leaf extract, high-purity stevia, or rebiana, has a steviol glycoside level of at least 95%. Major regulatory organizations, such as the Joint Food and Agriculture Organization/WHO Expert Committee on Food Additives4 and Codex, only authorize high-purity stevia extracts satisfying this standard for use in foods and beverages. Purified steviol glycosides are referred to as “stevia” throughout this article for the sake of simplicity.
Foods and beverages with stevia
Food experts are still looking for new applications for stevia-based sweeteners. Soft drinks, canned fruit and jams, ice cream and other dairy products, cakes and desserts, and alcoholic beverages are among the suggested uses for high-purity stevia leaf extracts.
Metabolism of stevia
Steviol serves as the building block for all steviol glycosides, and different glycoside (glucose) groups link to it to create the range of sweet chemicals in stevia.
Steviol glycosides are completely unharmed as they transit through the upper gastrointestinal tract. By chopping off their glucose units, gut bacteria in the colon hydrolyze steviol glycosides into steviol. The liver is then predominantly responsible for metabolizing steviol, which results in steviol glucuronide, which is primarily eliminated in the urine. Steviol is then absorbed via the portal vein. According to research, stevia (or any of its components or by-products) flows through the body during metabolism rather than accumulating there. Since the energy produced by the fermentation of glucose units is typically only 2 kcal/g, stevia can be considered to have no caloric value.
High-purity stevia leaf extract has no calories because it is not digested.
Safety of Stevia
The quantity of a drug that people can regularly eat in food or beverages over their entire lives without posing a significant risk to their health is known as the Acceptable Daily Intake (ADI). More than 200 peer-reviewed research on humans and animals looking at the safety of high-purity steviol glycosides have undergone thorough evaluation by a number of regulatory bodies. JECFA has produced an ADI that is applicable to both adults and children based on this evidence. The ADI is defined as 4 mg/kg of body weight of steviol equivalents per day. 7 Using a conversion factor of 0.33, this translates to roughly 12 mg of high-purity stevia extracts per kg of body weight each day. This ADI was created using a safety factor of 100, which includes a 10-fold factor to take into account potential differences between people and the animal species used in toxicological testing as well as a 10-fold factor to take into account potential variations within the human population, such as between children and adults. Therefore, any potential difference in steviol glycoside sensitivity between children and adults has been taken into account in the development of the ADI. For instance, to maximize, the current ADI for high purity steviol glycosides, a 150 lb (70 kg) individual would need to consume roughly 40 packets of a tabletop stevia sweetener daily for a lifetime. Each packet contains 21 mg of steviol glycosides. The math is as follows: A 70-kg person would ingest 70 12 = 840 mg of steviol glycosides per day if they followed the ADI (12 mg/kg per day). To optimize the current ADI, this person would have to take 840 / 21 = 40 tiny tabletop packets per day, which is around 21 mg of steviol glycosides each tabletop packet.
More than 200 research have demonstrated the safety of stevia, and JECFA has set an ADI of 4 mg/kg body weight per day, expressed as steviol equivalents, to assure consumers of its safety.
Stevia’s use in reducing energy intake and managing weight
There are 4 specific questions that must be addressed in order to adequately explore this matter:
- Does sugar increase energy consumption, leading to weight gain and obesity?
- Do sugar-sweetened drinks (SSBs) encourage people to consume more calories and become overweight or obese?
- Does substituting nonnutritive sweeteners (NNS) for caloric sweeteners promote weight loss or weight maintenance by assisting in lowering energy intake?
- Does switching to stevia from caloric sweeteners aid in weight loss or weight maintenance by lowering calorie intake?
Does Sugar Increase Energy Intake and Increase Risk of Overweight and Obesity?
One of the reasons a favorable European Food Safety Authority opinion was not issued in 2011 for NNS lowering obesity was the statement that “epidemiological studies do not reveal a positive link between total sugar intake and obesity.”
8 In the years since, a significant systematic review and meta-analysis,9 commissioned by WHO, came to the following conclusion: “Altering intakes of sugars, or SSB, is associated with changes in body weight (more consistently in adults than in children), which seem to be mediated via changes in energy intake because the isoenergetic exchange of sugars with other carbohydrates is not associated with weight change.” Consequently, sugar does appear to contribute to consuming more calories, but it cannot be proven that sugar directly causes obesity.
Do SSBs Affect Overweight and Obesity and Increase Energy Intake?
Interesting perspectives have been offered on all sides of this issue throughout the current heated debate (see Kaiser et al10 and Hu11). The argument centers on which types of evidence—randomized controlled trials [RCTs] and cohort studies, or only RCTs—should be taken into account and how the data should be interpreted for policymaking.
15 prospective studies, 5 RCTs, and 7 cohort studies in children, as well as 5 trials in adults, were included in the most recent systematic review to answer issue 2. It came to the conclusion that SSB use encourages weight growth in both kids and adults. 12 The 15 RCTs on children demonstrated that using NNS in place of SSBs reduced body mass index increase and that these advantages were more prominent in overweight children than in normal-weight children. The results were much better than those obtained with education initiatives that were based on schools. The two most recent experiments, where great care was taken to hide the identification of the NNS sweetened drinks, showed the biggest impacts. 13,14 In one trial13, sucralose and acesulfame potassium were used in place of sugar, whereas “diet drinks” containing an unidentified sweetener were used in place of sugar in the other SSBs. 14 However, it should be emphasized that the latter experiment did not find an effect at 2 years, which was the primary outcome determined. Instead, it did find an effect at 1 year. In reality, only the most obese boys showed an effect in a previous study by these investigators. 15
Does Switching to NNS from Caloric Sweeteners Facilitate Weight Loss or Weight Maintenance by Aiding in Energy Intake Reduction?
We published a systematic review and meta-analysis in 2006 to examine the evidence regarding the impact of NNS, primarily aspartame, on adult energy intakes, weight loss, and weight maintenance. It discussed how much energy is made up of and whether consuming sweetened foods and beverages is a useful strategy for weight loss. 16 We showed that substituting NNS for sucrose in foods and beverages significantly reduces energy intake (by about 10%) and body weight, with an estimated weight loss rate of roughly 0.2 kg/week. There is some energy compensation, but it only amounts to around one-third of the energy restored, and it is probably less when soft drinks are used since liquids typically have less energy compensation than foods do. These findings and the compensation values, however, came from short-term research, and longer-term data were required to ascertain whether tolerance to the effects of NNS may be developed.
Separating studies on overweight people from those on normal-weight subjects resulted in some success.
17 The six relevant studies that were considered in this case collectively revealed no overall benefit. However, when the three experiments conducted on overweight participants were examined separately, these authors noted a sizable reduction in body mass index when sugar was replaced with NNS.
To explicitly answer question 3, “Does replacement of caloric sweeteners with NNS facilitate weight loss or weight maintenance by helping reduce energy intake,” we still urgently needed a systematic review and meta-analysis of high-quality longer-term current research. This was given in the middle of 2014. 18 Data from 15 RCTs, which offer the best quality of evidence for examining the potentially causal effects of NNS intake, showed, according to these authors, that substituting NNS options for their regular-calorie counterparts results in a modest loss of weight and may be a helpful dietary tool to increase compliance with weight loss or weight maintenance plans.
Does Stevia’s ability to replace caloric sweeteners help people lose weight or maintain their weight by lowering their energy intake?
No long-term research has been reported that examines the efficacy of stevia in weight control, despite the fact that there have been several studies on stevia that have yielded data confirming its safety and that there is evidence that stevia does not impact satiety19. As stated above, numerous studies and overviews have, however, been released that detail trials conducted with various NNS, primarily aspartame. We have no reason to think that the success of stevia in replacing sugar in foods and beverages will result in a different outcome. Clarifying the function of stevia in long-term energy reduction will require additional human study.
Studies are required to verify the function of stevia in long-term weight loss and maintenance.
There are now more options for meals and beverages with less sugar and fewer energy thanks to the natural sweetener stevia. Stevia has the potential to help people consume fewer calories, which could help prevent and treat obesity.