STEVIA SWEETENERS: WHAT ARE THEY?
Stevia sweeteners are calorie-free sweeteners that can be used to reduce added sugar consumption while yet satisfying the desire for something sweet. They are collectively referred to as sugar substitutes, high-intensity sweeteners, non-nutritive sweeteners, or low-calorie sweeteners, even though some types of sweeteners in this category are low-calorie (like aspartame) and others are no-calorie (like stevia sweeteners, monk fruit sweeteners, and sucralose).
Stevia sweeteners are quite sweet, just as other calorie-free sweeteners. Because stevia sweeteners can be 200–350 times sweeter than sugar, very little of them are required to provide the same sweetness as sugar. Manufacturers of food and drink items can utilise stevia sweeteners as an ingredient in syrups, canned fruits, condiments, dairy products (including ice cream, flavoured milk, and yoghurt), and other foods (such as baked goods, cereals, chocolate, and other confections). Stevia sweeteners can be used in baked goods because they remain stable at high temperatures. A recipe that substitutes stevia sweeteners for sugar, however, might come out a little bit different because, in addition to sweetness, sugar also affects volume and texture in recipes differently depending on the type of recipe.
WHERE DO STEVIA SWEETENERS COME FROM?
The leaves of the South American herbal shrub Stevia rebaudiana (Bertoni) are used to make stevia sweeteners. For hundreds of years, the stevia plant has been utilised for food and medicine, and its leaves and unprocessed extracts have been offered for sale as dietary supplements. Steviol glycosides, which are extracted from the stevia plant’s leaves and purified to remove some of the bitter properties present in the crude extract, are used to make stevia sweeteners. All steviol glycosides share the steviol basic backbone. They consist of substances such as stevioside and a variety of rebaudioside, the most popular of which being rebaudioside A. (or reb A). 1 Additionally, some steviol glycosides can be generated on a bigger scale using procedures like bioconversion and fermentation that result in rebaudioside with superior flavour and less bitterness, like reb M.
AFTER CONSUMPTION, WHAT HAPPENS TO STEVIA SWEETENERS?
Steviol glycosides do not contain any calories and have no effect on blood sugar levels because they are not absorbed in the upper gastrointestinal tract. Gut microorganisms split off the glucose molecules as they get to the colon and consume them as fuel. Following this, the liver breaks down the residual steviol backbone, which is subsequently absorbed by the portal vein and eliminated in urine.
CAN PEOPLE CONSUME STEVIA SWEETENERS?
YES. The U.S. Food and Drug Administration uses the regulatory review procedure category known as “Generally Recognized As Safe” (GRAS) for high-purity steviol glycosides (FDA). GRAS demands professional agreement that a food ingredient is secure for usage as intended. Rebaudioside A, a stevia sweetener refined from Stevia rebaudiana, received the FDA’s first GRAS designation in 2008. (Bertoni). Because there is insufficient toxicological data available, the FDA has not approved the use of whole stevia leaves or crude stevia leaf extracts as food additives. 3 However, the FDA does not have any restrictions on the use of stevia leaves and unprocessed stevia leaf extracts in dietary supplements.
Leading international health organisations including the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the European Food Safety Authority (EFSA) have determined that high-purity steviol glycosides are safe to consume up to the recommended daily intake (ADI) level.
4,5,6 Food Standards Australia New Zealand, Health Canada, and the Ministry of Health, Labour, and Welfare of Japan have all endorsed the safety of stevia sweeteners. Stevia sugar sweeteners are currently legal to use in more than 60 nations based on the findings of these international authorities. See “What is GRAS?” below for further information on the FDA GRAS procedure.
The JECFA has defined a group ADI for stevia sweeteners of four milligrammes (mg) per kilogramme (kg) of body weight per day of steviol equivalents because of the fact that all steviol glycosides are metabolised to the same end product, steviol. This is the same as 12 mg/kg of rebaudioside A and 10 mg/kg of stevioside per day, respectively, of body weight. For certain high-purity steviol glycosides extracted from Stevia rebaudiana leaves, the FDA refers to the ADI set forth by the JECFA (Bertoni).
The ADI is equivalent to a number of stevia sweeteners 100 times lower than that required to achieve a NOAEL in toxicity investigations. The ADI is a conservative estimate that won’t be attained by the great majority of people. Although there is little data on stevia sweetener consumption in the United States, estimates of daily intake are below the ADIStevia sweetener consumption worldwide continues to be much below the ADI. According to a 2018 scientific assessment, studies did since 2008 suggest no issues with the general population surpassing the ADI of the main low- and no-calorie sweeteners, including stevia sweeteners. 8 See “What Is an ADI?” below for further information on how ADIs are set.
WHAT DOES ADIS DO?
The average daily dose over a lifetime that is thought to be safe for human consumption, or acceptable daily intake, is known as the ADI.
The no-observed-detrimental-effect level, or NOAEL, which is the greatest intake level that has been found to have no adverse effects in lifetime studies in animal models, is divided by 100 to arrive at this value. Setting the ADI 100 times below the maximum amount determined in toxicological tests to have no harmful effects adds a margin of safety that aids in guaranteeing the safety of human intake.
WHAT IS GRAS?
Food additives (which must be reviewed by the FDA before receiving permission) or generally recognised as safe (GRAS) ingredients are the two types of food ingredients that are allowed for usage in the United States. Food ingredients must be secure and must adhere to the same strict food safety standards whether they are GRAS or food additives. An ingredient must fulfil one of the following two requirements in order to be deemed GRAS:
1) A history of safe use has been established, and a significant number of people consumed the ingredient prior to the enactment of the Food Drug and Cosmetic Act of 1958.
2) Scientific data and information about the safety and use of the ingredient are widely known and publicly available in scientific articles, position papers, etc., with a consensus among scientific experts that the ingredient is safe for its intended use.
ARE STEVIA SWEETENERS SAFE FOR CHILDREN TO EAT?
YES. Healthy youngsters and healthy adults both have the same stevia metabolism. 11 Therefore, it has been determined by the FDA and JECFA that high-purity stevia sweeteners are safe for kids to eat within the ADI.
Stevia sweeteners can enhance the sweetness of a child’s meals and drinks without increasing their consumption of calories or added sweets. Stevia sweeteners do not raise the risk of dental cavities because they are non-cariogenic. In recent decades, efforts to reduce added sugar intake have led to an increase in the variety of food and beverage products that use low-calorie sweeteners. The present intake of low-calorie sweeteners is thought to be well below acceptable limits, despite observational research among children and adults showing an increase in the percentage of persons reporting daily usage of items containing low-calorie sweeteners. One modelling study predicted stevia sweetener intakes in kids with type 1 diabetes, who may be more likely to go over the ADI since they need to cut back on added sugars. The study’s authors came to the conclusion that there is little likelihood that kids with type 1 diabetes will go above the ADI for stevia sweeteners.
The American Heart Association (AHA) recommends water and other unsweetened beverages like plain milk for children instead of low-calorie sweetener-containing beverages.
Children with diabetes are one of the significant exceptions in the 2018 AHA science advisory, since their blood glucose management may be aided by consuming low-calorie sweetened beverages instead of sugar-sweetened ones. The 2019 policy statement from the American Academy of Pediatrics (AAP) does not recommend that children under the age of two consume foods or beverages that include low-calorie sweeteners, citing a lack of data as the reason. 15 The 2019 AAP policy statement does, however, acknowledge the potential advantages of low-calorie sweeteners for kids, including the potential to lower calorie intake, dental caries incidence, and glycemic response in kids with type 1 and type 2 diabetes. This is especially true for kids who are overweight. Dietary Guidelines for Americans (DGA) 2020–2025 states that children under the age of two should not consume added sugars or low-calorie sweeteners. 16 This DGA suggestion is meant to prevent infants and toddlers from developing a preference for extremely sweet foods at this formative stage rather than being related to body weight, diabetes, or the safety of added sugars or low-calorie sweeteners.
ARE STEVIA SWEETENERS SAFE FOR WOMEN WHO ARE PREGNANT OR NURSING?
YES. While there hasn’t been any published research on the potential effects of purified steviol glycosides on pregnant and lactating women, several important studies in animals have shown no harmful effects on mothers or their offspring in terms of reproduction or development, even when animals were exposed to levels that were more than 100 times the ADI every day for extended periods of time. Stevia sweeteners are safe for the general population, including pregnant and nursing women, when ingested within the limits of the ADI, according to regulatory authorities including the EFSA, FDA, and JECFA who have reviewed the safety evidence. While being careful not to exceed their needs, all women who are pregnant or breastfeeding need the proper nutrients and calories for their baby’s healthy growth and development.
ARE STEVIA SWEETENERS SAFE FOR PEOPLE WITH DIABETES TO CONSUME?
YES. People with diabetes are frequently advised to substitute stevia-sweetened foods and beverages for those that are sweetened with sugar in order to satisfy their sweet tooth while controlling their carbohydrate intake. Numerous studies have demonstrated that stevia sweeteners have no effect on human blood glucose control or levels. The use of low-calorie sweeteners in diabetes self-care may help with better glycemic control, according to recent consensus statements by experts in nutrition, medicine, physical activity, and public health. These statements point to the neutral effects of low-calorie sweeteners on haemoglobin A1C, fasting and postprandial glucose, and insulin levels.
The safety and function of low-calorie sweeteners for diabetics have been discussed by international organisations of health professionals. According to the American Diabetes Association’s 2022 Standards of Medical Care in Diabetes, “for some people with diabetes who are accustomed to regularly consuming sugar-sweetened products, nonnutritive sweeteners (containing few or no calories) may be an acceptable substitute for nutritive sweeteners” (those containing calories, such as sugar, honey, and agave syrup). As long as people are not making up for the reduced-calorie and carbohydrate intake with more calories from other foods, the use of nonnutritive sweeteners can lower overall calorie and carbohydrate intake. Diabetes Canada and Diabetes UK accept similar claims on the security and potential usage of low- and no-calorie sweeteners, such as stevia sweeteners, for diabetics.
Despite these findings, several research raises concerns about the management of blood sugar and low-calorie sweets. Although certain observational studies have shown a link between the use of low-calorie sweeteners and the likelihood of developing type 2 diabetes, observational studies cannot establish causation. Reverse causality and confounding can affect the conclusions drawn from observational study designs. For instance, many studies fail to account for obese status, which is a major risk factor for both type 2 diabetes and prediabetes. This is a crucial omission since overweight and obese people frequently drink more low-calorie sweetened beverages than lean people do.
STEVIA claims to support weight loss and weight maintenance.
Weight loss and/or weight maintenance may be aided by substituting stevia-sweetened foods and beverages for those that contain full-sugar sweeteners. The largest continuous study of people who have successfully maintained weight loss after losing at least 30 pounds and keeping it off for more than a year is the National Weight Control Registry (NWCR). Over 50% of the 434 NWCR members who responded to an online survey said they routinely drank low-calorie beverages, and 78% said doing so helped them keep their calorie intake under control. Data from randomised controlled trials frequently disagree with findings from observational research looking at the effect of low-calorie sweeteners on body weight. According to certain observational studies, using low-calorie sweeteners is linked to increased body weight and waist circumference in people. The consumption of low-calorie sweeteners was linked to increased rates of adult obesity and cardiometabolic disease, as well as increases in body mass index (BMI), according to a systematic review and meta-analysis of observational studies published in 2017. While data from randomised trials has not shown the relationship between intake of low-calorie sweetened beverages and increased body weight in children and adolescents, observational studies have. 36 Other more recent systematic reviews and meta-analyses came to the conclusion that low-calorie sweetener consumption had a marginally favourable association with higher BMI but no association with body weight. Observational studies have limits, which should be noted even though they might be useful for developing hypotheses. Observational studies cannot establish causation and effect by their very nature. Instead, observational studies look at the relationship between a factor (such as reported stevia sweetener consumption) and a result (such as body weight or a health condition). Observational study associations may be the consequence of reverse causality or may be complicated by other factors. A typical illustration of this is when someone modifies their eating and drinking habits after learning that they have a sickness: The disease caused them to make these adjustments; the changes they made did not cause the disease.
Furthermore, because observational studies do not use randomization, they are unable to account for all of the potential exposures or influences that might be contributing to or impacting results. For instance, one theory holds that consumers may make up for “calorie-free” choices by consuming more calories at subsequent meals or future snacks. Consider someone who might justifiably purchase dessert at a restaurant because they ordered a diet soda with their meal: The calories in the dessert will certainly outweigh the calories you would have saved by choosing the diet drink. These extra calories could result in weight gain or stop weight loss from progressing. The “licencing effect” or “self-licensing” refers to this conduct, in which a person justifies giving into indulgences by coming up with excuses to make behaviour that is incongruent with their aims more tolerable. Scientific studies have shown no evidence that people habitually and consciously overconsume calories as a result of consuming low-calorie sweeteners or foods and beverages that contain them, however, it may happen sometimes. Additionally, it has been proposed that individuals who are already overweight or obese can start selecting low-calorie sweetened foods and beverages as a means of decreasing weight.
This makes it challenging to conclude that using low-calorie sweeteners can lead to weight increase because reverse causality might play a role. The World Health Organization-funded systematic review and meta-analysis published in 2019 advised focusing on plausible confounding and reverse causality when interpreting data from observational research on low-calorie sweeteners and health outcomes.
The use of low-calorie sweeteners instead of high-calorie ones results in a little amount of weight loss, according to data from randomised clinical studies, which are regarded as the gold standard for determining causative effects.
There may be benefits to weight management from stevia sweeteners, according to some research. The effects of consuming stevia sweeteners every day for 12 weeks were investigated in a 2020 randomised controlled study of two groups of healthy, normal-weight, adult non-habitual consumers of non-nutritive sweeteners. One group was told to sweeten their usual drinks with a few drops of stevia. Stevia and usage instructions weren’t given to the other group. After weeks six and twelve, participants in the stevia group kept their weight steady, whereas those in the control group had a considerable gain in weight.
The majority of scientific studies exploring the connection between the use of low-calorie sweeteners and body weight evaluate a variety of low- and no-calorie sweeteners, including blends. As part of a programme that includes 12 weeks of weight loss followed by 40 weeks of weight-maintenance interventions, over 300 individuals were randomly assigned to drink either water or low-calorie sweetened beverages for a year in a 2016 randomised clinical trial. In comparison to the water group, which lost 2.45 kg, individuals allocated to the low-calorie sweetened beverage group lost an average of 6.21 kg.
Although a few systematic reviews came to the conclusion that using low-calorie sweeteners did not cause considerable weight loss or increase, these conclusions seem to be the outcome of how the research is compared.
According to Mela et al., some study designs permit comparison of results between caloric and non-caloric options, whereas others do not.
Consuming low-calorie sweeteners can aid in weight loss by reducing overall caloric intake, according to a 2020 systematic review and meta-analyses of intervention trials.
Researchers looked at 88 sustained intervention studies that included relevant comparators and objective body weight and BMI measures. Low-calorie sweetener use decreased body weight, BMI, and total calorie intake when compared to sugar usage. There was no difference in body weight, BMI, or total calorie intake when low-calorie sweeteners were consumed versus water or nothing at all. Furthermore, there was no difference between taking low-calorie sweetener capsules and placebo capsules, proving that the way low-calorie sweetener consumption affects energy balance is through calorie displacement.
A systematic review of 37 studies on the impact of low- and no-calorie sweetened beverages on adiposity that were published between January 2000 and June 2019 was included in the Scientific Report of the 2020 Dietary Guidelines Advisory Committee (DGAC). Six of these studies were randomised controlled trials. Low- and no-calorie sweeteners should be thought of as a possibility for controlling body weight, according to the DGAC report. 54
It’s crucial to remember that maintaining a healthy weight entails using several strategies at once. One strategy is to make a single adjustment, such as switching to low-calorie sweetened products instead of full-calorie, sugar-containing items. Achieving weight loss and weight maintenance goals requires adopting the lifestyle and behavioural practices like eating healthfully, exercising frequently, getting enough sleep, and preserving social support networks.
DO STEVIA SWEETENERS ADD TO MY HUNGER?
Foods that are very tasty stimulate the reward and pleasure centres of the brain. If left uncontrolled, the increase in food intake that results from this favourable correlation may increase hunger, which has been speculated to raise the risk of overweight and obesity. By stimulating sweet taste receptors, low-calorie sweeteners can also stimulate reward pathways even when they do not contain calories.
Some people worry that triggering reward pathways without also giving the body sugar can have unforeseen repercussions. Following the use of low-calorie sweeteners, certain animal studies have shown changes in food intake and hormones linked to appetite. But no such effects have been observed in people. There is currently no conclusive proof that low- and no-calorie sweeteners, such as stevia sweeteners, increase human hunger or cravings. And some randomised studies have shown the opposite result, such as a decrease in hunger and a reduction in dessert consumption among those who drank low-calorie sweetened beverages as opposed to those who drank water. Others have demonstrated that stevia sweeteners have no impact on fullness. Results that can be attributable to the lower calorie content of the stevia sweetener intervention and the fact that participants did not make up for the loss by consuming more calories later in the day include a reduction in overall daily calorie consumption compared to a full-sugar control.
The impact of sweetness (with or without calories) on hunger and food intake was studied in a 2020 randomised controlled study. Researchers discovered that when compared to those who drank plain water, those who drank water sweetened with stevia reported fewer pre-meal hunger pangs. Additionally, they discovered that drinking water sweetened with stevia led to less subsequent food consumption than drinking water that had been plain, sweetened with maltodextrin, or sweetened with glucose or sucrose in equal amounts. In addition, a 2018 randomised controlled experiment showed that eating stevia-sweetened cookies reduced hunger compared to eating control cookies.
A GUTS MICROBIOME, WHAT ABOUT IT?
The microbes that inhabit our intestinal system are now recognised as potentially important contributors to human health, despite the fact that research on the gut microbiome is still in its infancy. 2003 in vitro study found that the composition of the human gut microbiome itself was not significantly affected by the metabolism of steviol glycosides, which has been demonstrated to have a modest impact on studies. However, human randomised clinical trials have not yet been carried out, and there is currently no proof that stevia sweeteners have any appreciable effects on the structure or operation of the gut microbiome.
A healthy human microbiome is not currently defined by any standards.
The microbiome profiles of different individuals differ significantly, and studies have shown that the gut microbiome can react fast to common dietary changes. 68 International specialists have emphasised that due to the wide range of microbiome profiles, it might be challenging to distinguish between healthy variation and harmful consequences.
There is no concrete proof that low-calorie sweeteners harm gut flora, according to a review of the literature published in 2019.
A group of specialists on low-calorie sweeteners reached a similar result in 2020 and stated that there is now insufficient data to prove that low-calorie sweeteners have any negative impacts on gut health at dosages appropriate for human use.
FINALLY, WHAT SHOULD WE SAY?
All kinds of meals and drinks, including those sweetened with stevia, can fit into a number of healthy eating regimens. Since 2008, stevia sweeteners have been approved for general use in the United States, and other international health organisations have confirmed its safety. Low-calorie sweeteners have been examined for their effects on and links to long-term diseases like obesity and type 2 diabetes. Studies that relate low-calorie sweeteners to the risk of type 2 diabetes and weight gain are observational in nature, which makes it impossible to prove a cause-and-effect relationship. These studies also have problems with confounding and reverse causation. Contrarily, low-calorie sweeteners can be helpful in nutritional regimens to support weight loss and/or weight-maintenance objectives, according to numerous randomised controlled trials. In randomised controlled trials, stevia sweeteners had no detrimental effects on insulin or blood sugar levels. The available data does not indicate that low- and no-calorie sweeteners, such as stevia sweeteners, have a negative impact on the gut microbiome, even if the role of the gut microbiome in health is still being investigated.
To promote one’s wellbeing, it is essential to living a healthy, active lifestyle that is suited to individual objectives and priorities. One way to reduce consumption of added sugars and keep calories under control—important elements in maintaining health and lowering the risk for lifestyle-related diseases—is to choose foods and beverages sweetened with low- and no-calorie sweeteners like stevia sweeteners.
