The stevia plant has been used for more than 1,500 years by the Guaraní people of Brazil and Paraguay, who refer to stevia as ka’a he’ê, which means “sweet herb.” These native South Americans love using this non-caloric natural sweetener in their yerba mate tea, as medicine and a sweet treat. (1) In these South American countries, stevia has also been used specifically as a traditional medicine for burns, stomach problems, colic and even as a form of contraception. So, if it’s such a sweet treat, are there stevia side effects that may make it bad for you?
Stevia extract averages about 200 times sweeter than sugar, depending on the specific stevia compound discussed. When it comes to using stevia, you only need a tiny bit at a time to sweeten your morning tea or next batch of healthy baked goods. Stevia side effects are typically not common, especially if you choose the right stevia product.
Several articles and other sources online claim that there may be some negative stevia side effects. This can be confusing, as many of my readers ask why this could be, if stevia is an herb and touted as one of the healthiest natural sweeteners around. I’m going to lay out for you both the good and the bad about how stevia side effects may affect your health, as well as the distinctions between the many types of stevia.
What Is Stevia?
There are approximately 200+ species of stevia that grow in South America. What is stevia? It’s an herbal plant that belongs to the Asteraceae family, which means it’s related to ragweed, chrysanthemums and marigolds. Stevia rebaudiana is the most prized variety of stevia, and the cultivar used for production of edible stevia products.
In 1931, chemists M. Bridel and R. Lavielle isolated the two glycosides that make stevia leaves sweet: stevioside and rebaudioside (with five variations: A, C, D, E and F). Stevioside is sweet, but also has a bitter aftertaste that many complain about when using stevia, while isolated rebaudioside is sweet without the bitterness.
Many raw or less processed stevia products contain both types of stevia compounds, whereas most highly processed forms of stevia only contain the rebaudiosides, the sweetest part of the stevia leaf. Rebiana, or high-purity rebaudioside A, is generally recognized as safe by the Food and Drug Administration (FDA) and may be used as an artificial sweetener in foods and beverages. (2)
As you’re about to see in the research, using the whole stevia leaf or purified rebaudioside A has some great health benefits, but the same benefits may not hold true for altered stevia blends that actually contain very little of the plant itself.
Is Stevia Safe? Are There Stevia Side Effects?
Most people do well with stevia, but listen to your body: Stevia is an herb, and everyone’s body may react differently to it. The benefits and possible stevia side effects really depend upon what stevia you choose to consume. A study to test the long-term side effects of stevia reported that none of the 76 subjects (some of whom had type 1 or type 2 diabetes) experienced any significant side effects. (3)
Highly refined and purified glycosides of stevia are considered by the FDA to be generally recognized as safe (GRAS) as sweeteners in food. The FDA has not approved whole-leaf stevia or crude stevia extracts as GRAS for food because they don’t feel the safety of these unprocessed extracts has been proven; however, they may be used in dietary supplements. (4, 5)
A 1999 study indicates stevia may decrease the fertility of male animal subjects. The amount of stevia was not specified in the study abstract, but stevia was administered for 60 days. The concern is that stevia extracts could affect hormones because its glycosides have a similar structure to plant hormones like gibberellin. (6) However, many herbs, including ginkgo biloba, also have this natural component, and if consumed in moderation, it seems to be safe.
In fact, as I discuss further in the “Precautions” section below, these 1999 study results have never been replicated, although many researchers have performed similar trials.
In theory, stevia could cause allergic reactions in people with an allergy to ragweed (since they belong to the same plant family). But this has never been reported nor studied in structured research.
Other general side effects that are warned of with stevia are bloating, nausea, dizziness, numbness and muscle pain. These are reported by WebMD but haven’t been observed in scientific study.
Three Types of Stevia
When it comes to the stevia options available today, it’s vital to know that not all stevia is created equal. In fact, there has been concern in recent years about counterfeit stevia, or stevia products laced with unwanted ingredients, which is one likely reason the FDA has been slow to approve all stevia as GRAS. (7)
For our purposes, I want to explain the three main categories of stevia, including green leaf stevia, stevia extracts and altered stevia blends.
Green leaf stevia is the least processed of the stevia types. The leaves are dried and ground into powder form. This is the type of stevia that’s been used in South America and Japan for centuries as a natural sweetener and health remedy. Green leaf stevia is only about 10-15 times sweeter than sugar. (8) This unprocessed version more than likely contains a combination of steviosides and rebaudiosides.
Second, you have purified stevia extracts. If you’re eating stevia in the US (available in the food section of your grocery store), you are consuming rebaudioside A in either a pure extract or our third type of stevia (altered stevia blends). Per FDA standards set forth in 2008, these extracts must contain over 95% or more pure rebaudioside A glycosides and may not contain other forms of rebaudiosides or steviosides in order to be legally marketed as food. (8) While purified stevia extracts are more processed than green leaf stevia, their health benefits seem to be on par with its unprocessed counterpart.
From what I have seen, the least healthy option is altered stevia blends. By the time a product like this is placed on a shelf, very little of the stevia plant remains. Some companies use processes to create these blends that include chemical solvents, including acetonitrile, which is toxic to the central nervous system, and a GMO corn derivative called erythritol. (9) The small amount of remaining stevia contains rebaudioside A only in the US.
Many purified stevia extracts and altered stevia blends are reported to be 200-400 times sweeter than sugar. (10)
This point cannot be stressed enough: Not all stevia products are created equal. I consider there to be a huge difference between consuming real stevia and chemically altered stevia blends (some of which contain as little as 1 percent of stevia in their final form!).
5 Health Benefits of Stevia
Now, on to the good stuff! There are several studies (589 stevia studies as of this writing to be exact, and that number is ever-increasing) available on PubMed, by the National Institute of Health, evaluating stevia’s features, growth and impact on health. There are medicinal properties in the plant itself that lend to its incredible health benefits.
1. Anticancer Abilities
In 2012, Nutrition and Cancer highlighted a groundbreaking laboratory study that, for the first time ever, connected stevia consumption to breast cancer reduction. It was observed that stevioside enhances cancer apoptosis (cell death) and decreases certain stress pathways in the body that contribute to cancer growth. (11)
The journal Food Chemistry published a study out of Croatia showing that when stevia is added to natural colon cancer-fighting mixtures, such as blackberry leaf, antioxidant levels soar (when tested in a lab). (12) Together, these studies suggest stevia’s potential as a natural cancer treatment.
2. Sweet News for Diabetics
Using stevia instead of white sugar can be extremely helpful to diabetics who need to avoid conventional sugar as much as possible on a diabetic diet plan — but, they also shouldn’t have chemical-laden, unhealthy sweeteners. Human and animal studies have demonstrated that some non-nutritive sweeteners (containing no calories) can raise your blood sugar levels even more than if you consumed the real stuff (table sugar). (13) That should make you think twice before picking up another diet soda.
Enter: stevia. An article published in Journal of Dietary Supplements evaluated how stevia affects diabetic rats. It was discovered that rats treated with 250 and 500 milligrams every day “significantly” reduced fasting blood sugar levels and balanced insulin resistance, triglycerides and alkaline phosphatase (which can be raised in cancer patients). (14, 15)
Another study of male and female human subjects found that having stevia before a meal reduced after-meal blood glucose and insulin levels, and was unaffected by other reductions in the calories consumed. This research demonstrates how stevia may aid in glucose regulation. (16)
3. Supports Weight Loss
Consuming added sugars has been shown to contribute an average of more than 13 percent of the total calories each day in the American diet. (17) This high sugar intake has been linked to weight gain and adverse effects on blood sugar, two things that can have serious negative impacts on health.
Stevia is a plant-based, zero-calorie sweetener. If you choose to replace health-hazardous table sugar with a high-quality stevia extract and use it in moderation, it can help you decrease not only your overall daily sugar intake, but also your caloric intake. By keeping your sugar and calorie intake in a healthy range, you can help fend off obesity as well as many health problems linked with obesity, like diabetes and metabolic syndrome.
4. Improves Cholesterol Levels
Results of a 2009 study showed that stevia extract had “positive and encouraging effects” on overall cholesterol profiles. It’s important to note that researchers also found that there were no adverse stevia side effects on the health status of the subjects involved in this stevia study. Researchers concluded that stevia extract effectively decreased elevated serum cholesterol levels, including triglycerides and LDL (“bad cholesterol”), while increasing good HDL cholesterol. (18)
5. Lowers High Blood Pressure
“Available research is promising for the use of stevia in hypertension,” says Catherine Ulbricht, senior pharmacist at Massachusetts General Hospital in Boston and co-founder of Natural Standard Research Collaboration, which reviews scientific evidence on herbs and supplements. Ulbricht’s research company gave stevia a “grade B for efficacy” in reducing blood pressure. (19)
Certain glycosides in stevia extract have been found to dilate blood vessels and increase sodium excretion, two things that are very helpful to keeping blood pressure at a healthy level. Evaluation of two long-term studies (one and two years in length, respectively) gives hope that stevia may be effective in lowering blood pressure in hypertensive patients. However, data from shorter studies (one to three months) did not support these findings. (20, 21)
Organic Stevia vs. Non-Organic Stevia
- Made from organically grown stevia
- No glycemic impact
- Naturally gluten-free
Unfortunately, even some organic stevia contains fillers. Some aren’t truly pure stevia, so you should always read labels if you’re looking for a 100 percent stevia product. For example, one brand of organic stevia is actually a blend of organic stevia and organic blue agave inulin. Agave inulin is a processed fiber derivative from the blue agave plant. While this filler is not as concerning as a GMO ingredient, it’s still a filler.
- Does not have to be made from organically grown stevia, meaning it may be laced with pesticides or other chemicals
- Non-GMO (there are currently no genetically modified cultivars of stevia in the world)
- No glycemic impact
- Naturally gluten-free
With non-organic brands of stevia, it’s very important to look for additional ingredients, like erythritol, inulin or any other ingredient besides stevia. Although stevia itself is always non-GMO, many non-organic stevia products are combined with erythritol or other dangerous non-nutritive sweeteners, many of which are made from GMO ingredients like corn.
Stevia vs. Sugar and Other Sweeteners
Why replace sugar with anything? Is sugar bad for you? Yes, it absolutely is! Heavy sugar consumption is linked to heart disease, non-alcoholic fatty liver disease, leaky gut, type 2 diabetes and even cancer. Just one teaspoon of conventional table sugar contains 16 calories and 4.2 grams of sugar. (22)
Unfortunately, many people turn to any number of unhealthy non-nutritive (no-calorie) artificial sweeteners to beat sugar addiction. Some of these are downright dangerous, which is why I stick to stevia.
Unlike stevia, most artificial sweeteners are linked to concerning health effects, similar to sugar. For example, aspartame (found in most diet sodas and many “sugar-free” foods) is associated with a higher risk of heart disease, larger body mass index (BMI), higher cancer risk, a potential to induce or worsen diabetes, central nervous system disruption, mood disorders, fibromyalgia, premature menstruation, autism rates and kidney disease. (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
Another popular artificial sweetener, sucralose, has been presented to many people as a healthy alternative to aspartame since its approval in the 1990s. However, there are reports that sucralose may also be problematic, particularly because the body metabolizes it differently than most artificial sweeteners. It is also a mutagenic substance, which means it can interfere with DNA at certain concentrations. Sucralose has been thought to be safe in high-heat cooking, but a 2013 report reviewing the safety of this substance found that it generates chloropropanols when cooked at high heat, which are considered probably environmental contaminants and toxins. In addition, sucralose interacts with insulin levels, which non-nutritive sweeteners aren’t supposed to do. (38)
One 2016 research study studied the carcinogenic potential of sucralose, finding a significant enough instance of cancer in sucralose-exposed subjects that researchers concluded: “Considering that millions of people are likely exposed, follow-up studies are urgent.” (39)
To avoid artificial sweeteners, many people choose items sweetened with sugar alcohols, such as erythritol, xylitol, mannitol and sorbitol). While these aren’t exactly the same as artificial sweeteners in their composition and, indeed, don’t cause spikes in blood sugar like table sugar does, they are associated with side effects like bloating, diarrhea, gas and may even impact blood sugar for people with type 1 diabetes. (40) In addition, these are often extracted from GMO corn, which comes with its own list of problematic effects.
While I still recommend any sweetener in moderation, it’s clear at this point why I don’t recommend conventional sugar, sucralose, aspartame or sugar alcohols as worthwhile sweeteners. For a no-calorie sweetener that benefits my body, I stick to stevia.
Other natural sweeteners I enjoy include raw honey, dates, coconut sugar, maple syrup, blackstrap molasses, balsamic glaze, banana puree, brown rice syrup and real fruit jam. Keep in mind that these do impact caloric intake and blood sugar; however, they have healthful benefits to consider, rather than significant dangers to avoid.
Best Place to Find + How to Use Stevia
Stevia is available online or at most local grocery stores, both in powdered and liquid form. Keep in mind: The best stevia will have no additives, including other sweeteners, and is USDA certified organic and non-GMO certified.
For green stevia leaf (technically considered a supplement in the US, not a food), I stick to Organic Traditions Organic Green Leaf Stevia Powder®. When I eat purified stevia extract (the only food-approved stevia in the US), I like SweetLeaf® Stevia, which is available in liquid and white powder forms.
You may also buy whole dried leaves and grind them at home, although it’s recommended you don’t use homegrown stevia for baking or cooking because of the chemical reactions that may occur.
Stevia is available in both powders and liquid forms. The liquid varieties are useful for sweetening coffee, teas or healthy smoothies. Powders work best for cooking and baking — and a little goes a long way.
Try these basic conversions the next time you replace sugar with stevia: (41)
- 1 teaspoon sugar = 1/2 packet or 1/8 teaspoon powdered stevia = 5 drops liquid
- 1 tablespoon sugar = 1.5 packets or 1/3 teaspoon powdered stevia = 15 drops liquid stevia
- 1 cup of sugar = 24 packets or 2 tablespoons powdered stevia = 2 teaspoons liquid stevia
The only substitution that won’t work is caramelization in desserts, as stevia doesn’t brown like conventional sugar.
How Much Stevia Can I Have Every Day?
The acceptable daily intake (ADI) of steviosides is 5 milligrams per kilogram of body weight each day, and 4 milligrams per kilogram of body weight of rebaudiosides. When using stevia, it’s best to stay at or under this amount. Stevia rebaudiosides make up about 1/3 of the total weight of final, purified stevia product (not altered or combined with other ingredients).
Using this math, the ADI of FDA-approved purified stevia extract each day comes to 12 milligrams per kilograms of body weight.
- 100 pounds — up to 540 mg/day — up to 3 ½ tsp/day — up to 14 drops
- 150 pounds — up to 340 mg/day — up to 5 ½ tsp/day — up to 22 drops
- 200 pounds — up to 454 mg/day — up to 7 ½ tsp/day — up to 30 drops
- 250 pounds — up to 567 mg/day — up to 9 tsp/day — up to 36 drops
For comparison, one packet of stevia is equal to one teaspoon. This is about the same amount as four drops of liquid stevia.
If you’re using green leaf stevia powder, the numbers are slightly higher, but the ADI for green leaf stevia comes from other countries, as the US has not approved it for use in food.
Scientifically, these numbers are established by scientists using a safety factor of 100. This means that stevia has been tested in studies at a level 100 times higher than the final ADI without problematic results. (42)
Stevia Side Effects and Precautions
There are few side effects generally noted with stevia, although it theoretically could cause an oral allergic reaction in people with ragweed allergy because they are from the same family and have similar molecular structures. No reported cases of an allergic reaction like this has ever been reported to the best of my knowledge and research, and no research study has been performed to test this potential issue.
Signs of an oral allergic reaction include swelling and itching of the lips, mouth, tongue and throat, hives, abdominal pain, nausea, vomiting and a tingling sensation in the mouth and throat. Discontinue use if this occurs, and seek medical attention if symptoms are serious.
According to the extensive research available, stevia is not mutagenic or carcinogenic (like other artificial sweeteners tend to be). (44)
In the past, stevia has been approached with caution for pregnant and breastfeeding moms. However, many studies have been done in animals to observe whether fertility or birth outcomes change with stevia doses. The conclusion? A dose of stevia even several times higher than the ADI doesn’t seem to have any effect on fertility or birth outcomes (meaning live birth rates, birth defects and malformations, etc.). (45, 44)
As I stated above, long-term studies have reported no side effects from any study participants consuming stevia at normal ADI or therapeutic levels, which are higher doses intended to treat a condition. (3)
A popular cited study regarding precautions for non-nutritive sweeteners (including stevia as well as aspartame, sucralose, acesulfame-K and others) states that these have been shown to alter the gut microbiome and could potentially interact with immunity or any of the other important functions housed in the gut. Interestingly, the only negative gut effects have been observed in studies about other non-nutritive sweeteners, but not stevia. (46)
Some people find that stevia can have a metallic aftertaste.
In general, it’s a good idea to seek medical advice before using stevia if you have an ongoing medical condition or take other medications. There aren’t any contraindications (interactions) with medications at present, but your healthcare provider will help to give you advice to make sure you don’t use it in excess.
Final Thoughts on Stevia and Stevia Side Effects
Stevia is a no-calorie sweetener which, unlike many other non-nutritive sweeteners, is associated with several health benefits and negligible, if any, side effects.
The researched health benefits of stevia are:
- Anticancer abilities
- Sweet news for diabetics
- Supports weight loss
- Improves cholesterol levels
- Lowers high blood pressure
Depending on your body weight, you can have up to 3.5-9 teaspoons of stevia each day to stay within the FDA’s acceptable daily intake (ADI) of purified stevia. Amounts 100 times higher have been tested with no negative results in animals.
Stevia may have a slightly metallic aftertaste for some people. In long-term studies, stevia has been reported to cause no reportable side effects in humans, although WebMD warns of potential symptoms, including bloating, nausea, dizziness, numbness and muscle pain. These have not been duplicated in long-term studies in humans, however.
It’s possible stevia side effects may be pronounced in people with ragweed allergy, but this has not been reported or studied.
Stevia is my number one (and only) pick for non-nutritive (no-calorie) sweeteners, and on the top of my list overall for healthy natural sweeteners. As with all sweet things, it’s best to use stevia in moderation.
Read Next: 5 Best Sugar Substitutes
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