After cutting back on sugar and carbs for a while, you understandably start to miss sweets. A common misconception is that you have to skip sweets to meet your goals, which isn’t the case at all. There are plenty of sugar alternatives that fit within the Primal and keto lifestyles, and stevia is one of them.
Stevia is widely used in the low carb community to satisfy sugar cravings or simply add a touch of sweetness to a hot beverage or dessert, but should it be? What is stevia? Is it safe? What is its effect on insulin, if any, and does it have a place in a Primal Blueprint eating strategy? Let’s investigate.
What Is Stevia?
A lot of people categorize stevia as an artificial sweetener, but it’s important to note that stevia is not an artificial sweetener at all – it’s a plant-derived natural alternative to sugar.
Stevia is an herbaceous family of plants, 240 species strong, that grows in sub-tropical and tropical America (mostly South and Central, but some North). Stevia the sweetener refers to stevia rebaudiana, the plant and its leaves, which you can grow and use as or with tea (it was traditionally paired with yerba mate in South America) or, dried and powdered, as a sugar substitute that you sprinkle on. It’s apparently quite easy to grow, according to the stevia seller who tries to get me to buy a plant or two whenever I’m at the Santa Monica farmers’ market, and the raw leaf is very sweet.
The Sweet Compounds in Stevia: Stevioside and Rebaudioside
Most stevia you’ll come across isn’t in its raw, unprocessed form, but in powdered or liquid extract form. The “sweet” lies in the steviol glycosides – stevioside and rebaudioside – which are the natural compounds isolated in these extracts. Some products use just one, while others use both stevioside and rebaudioside. Stevioside is the most prevalent glycoside in stevia, and some say it provides the bitter aftertaste that people sometimes complain about; rebaudioside is said to be the better tasting steviol glycoside, with far less bitterness.
Most of the “raw or natural” stevia products use the full range of glycosides, but the more processed brands will most likely isolate one or more of the steviol glycosides. The popular Truvia brand of stevia products uses only rebaudioside, as do both PureVia and Enliten. Different brands provide different conversion rates, but compared to sucrose, stevioside is generally about 250-300 times as sweet and rebaudioside is about 350-450 times as sweet.
Is Stevia Safe, or Bad for You?
The government has approved only isolated steviol glycosides as safe to use in food. Whole or crude stevia is not Generally Recognized as Safe (GRAS) according to government standards.1
And, there are limits. According to government standards, you should not exceed a daily intake for stevia glycosides of 4mg per kg of bodyweight.2 This is due to lack of safety information, not so much the presence of known harmful effects.
Does Stevia Affect Insulin?
I wrote an extensive piece on whether artificial sweeteners spike blood sugar a while back. There is one in vitro study that showed stevioside acts directly on pancreatic beta cells to stimulate insulin secretion and another which shows similarly insulinotropic (insulin-producing) effects of rebaudioside, which may give you pause.
Insulin secretion sounds like an insulin spike, no? And since we tend to be wary of unneeded insulin spikes, maybe we should avoid stevia. It’s not so simple, of course. For one, this was an in vitro study, performed in a super-controlled laboratory petri dish type setting; this was not an in vivo study of animals or people eating stevia in a natural, organic way. The results of in vitro studies do not always match results when you try to replicate them in vivo (in a person).
Secondly, insulin secretion isn’t necessarily a bad thing. I mean, we need it to shuttle nutrients into cells, and we’d die without it. As I mentioned in the dairy post a while back, insulin is millions upon millions of years old. It’s been preserved throughout history because it’s an essential hormone. It’s not always the bad guy, especially if your insulin sensitivity is where it should be.
In fact, the evidence is mounting that stevia actually is an insulin sensitizer that can aid in glucose tolerance and clearance after a meal. The Japanese have been using stevia for decades in the treatment of type 2 diabetics. Let’s look at a few recent studies. In fructose-fed rats, a single instance of oral stevioside increased insulin sensitivity and reduced postprandial blood glucose in a dose-dependent manner. The same study also found that diabetic rats given stevioside required less exogenous insulin for the same effect. Taken together, these results suggest that stevia may not just be a good sugar substitute for diabetics, but an effective supplement for treatment of their insulin resistance.3
Another study looked at the postprandial effects of stevia, sucrose, and aspartame in human subjects. Compared to sucrose eaters, stevia eaters showed lower postprandial (after eating) blood sugar levels. Compared to both sucrose and aspartame eaters, stevia eaters had far lower postprandial insulin levels. Furthermore, eating stevia did not induce increased appetite throughout the day, indicating stable blood sugar and satiety levels.4 Another strike in stevia’s favor.
Allergy to stevia has been reported, but it is rare.
Most people do not experience side effects when using stevia, but some people do experience effects like:
Most often these effects are from using stevia that is mixed with sugar alcohols, like erythritol or xylitol. If you can tolerate sugar alcohols, you will probably be okay using combination stevia and sugar alcohol products. To be sure, start slow, and watch for symptoms.
Stevia is considered safe for the diabetic population, but sometimes it is combined with ingredients that affect carb count, like dextrose and maltodextrin. If you’re diabetic, check your ingredients label and carb counts before adding it to food.
Historically, stevia has been used as a form of birth control, so use of stevia may contribute to fertility issues.5 That said, it is not a reliable form of birth control, so it’s not advisable to use it for that purpose.
Any Other Effects?
There are other potential benefits to using stevia unrelated to its apparent benefits on glycemic control. Here are a few studies I was able to dig up:
When combined with inulin, a soluble prebiotic fiber, low-dose stevia increased HDL while lowering overall lipids in male rats.6 Alone, low-dose stevia lowered cholesterol without the potentially beneficial effect on HDL. It’s also useful to note that high-dose stevia negatively affected some toxic parameters – so don’t eat spoonfuls of stevia (not that you would) – but long term low-dose stevia was deemed safe.
Lipid numbers are fun and all, but we’re really interested in avoiding atherosclerotic plaque buildup. In mice treated with stevioside, oxidized LDL was reduced, overall plaque volume was reduced, and insulin sensitivity increased. Overall, atherosclerosis was reduced in the stevioside-treated mice.7 I couldn’t dig up exactly how they were “treated,” however, but they were given doses of 10 mg/kg.
In another study, mice memory was impaired by administration of scopolamine, an anticholigernic found in the intensely hallucinogenic jimson weed (or devil’s weed) and datura. Impaired mice were given oral stevioside (250 mg/kg) and tested for memory retention. Memory deficit was largely reversed with administration of stevioside, which also reduced the brain oxidative damage caused by scopolamine.8 Clinically relevant? Perhaps not, but it’s interesting.
A two-year randomized, placebo-controlled study of Chinese patients with mild hypertension (which a rather large swath of society probably suffers from) found that oral stevioside intake significantly reduced systolic and diastolic blood pressure.9 Patients either took a 500 mg capsule of stevioside or a placebo three times a day for two years. The hypertension situation improved across the board and no downsides were reported or detected. Also of note is the fact that slightly more patients in the placebo group developed left ventricular hypertrophy, a pathological thickening of the heart muscle. Of course, another study using far lower doses (up to 15 mg/kg/day) found no anti-hypertensive effects,10 so it appears that the dose is key. Maybe somewhere in the middle works well, as one study in hypertensive dogs showed: they used 200 mg/kg to normalize blood pressure in the canine subjects.11
We can think about stevia as a Primal sugar alternative with some potentially beneficial effects. Kind of like cinnamon or turmeric, we don’t consume it for the calories or as literal fuel for our bodies, but for flavor, variety, and, possibly, the health benefits. It may induce insulin secretion, but it increases insulin sensitivity, reduces blood glucose (i.e., the insulin is doing its job), and does not increase appetite. It’s been used by humans for hundreds of years and by diabetic patients in Asia for decades. I’m a fan of the stuff and recommend it as a Primal way to satisfy a sweet tooth.
What do you guys think of stevia? Love it? Hate it? Have you ever used its potential therapeutic effects? Let me know in the comment section!
Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.