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Is Stevia good or bad?

I received a ton of stevia products recently to sample, and  one of my pals asked for my thoughts, since she considered stevia “MUCH closer to natural than the sucralose process.” I’ll admit, the NuNaturals products I have sampled taste great, clean and sweet like sugar and the liquid form I was testing was very concentrated and only needed a few drops to make a cup of coffee taste great. It’s much better than the bitter-aftertaste, licorice tasting stevia I tried ages ago. But I don’t plan to include stevia as a regular sweetener in my diet.

Below are my thoughts on stevia, which I share with caution because I know many bloggers and blog readers do choose stevia over other sweeteners.

First, natural doesn’t carry any weight as far as making me trust something. Natural does not equal benign. Manmade does not equal harmful. Nature invented some powerful toxins and carcinogens, and theoretically one could use the “it’s natural!” line to excuse tobacco and numerous other harmful drugs.

Second, everything is toxic at high enough dose. Water. Salt. Alcohol. Potassium. You name it. My concern with sweeteners is: Is the level at which I would use them (or my clients) likely to pose a health risk?

I’ve been reviewing safety data on stevia literally all week, in my spare time (haha, I know what you’re thinking! when is that?) I regularly troll the literature for aspartame, sucralose studies as well, since I do consume both of them regularly.

To start, none of the three (stevia, aspartame, or sucralose) have demonstrated carcinogenicity at any level. Not in animals, not in people. Despite what you read in your email.

When toxicity is determined for a food additive, the general idea (really simplified explanation here) is that studies are conducted in animals to determine the NOAEL. No Adverse Effects Level. This is the highest dose at which no bad things happen to the critter. Expressed in mg/kg bodyweight.

Usually, to have a margin of safety, the NOAEL is divided by 100, and that smaller number (1% of the NOAEL) is set as the ADI (Acceptable Daily Intake) for humans. This is the maximum amount that a person is advised to consume (on a daily basis). So if 100 mg/kg bodyweight was the lowest dose at which something harmful was witnessed in an animal, the ADI for humans would likely be assigned at 1 mg/kg bodyweight.

With me still?

Okay, so ADI’s for common sweeteners:
Aspartame: 50 mg/kg
Sucralose: 5 mg/kg
Stevia glycosides: 4 mg/kg

One of the problems with Stevia products is that there are so many various formulations sold, each company’s product has a different amount of stevia glycosides in it. They don’t even need to disclose how much is in it accurately because stevia extracts and glucosides are usually sold as dietary supplements, not subject to FDA regulations. Some branded versions are purified Rebaudioside A (Reb A), some are a literal soup of compounds extracted from the plant. Could this make some products safer than others? Absolutely.

Stevioside, one of the sweet-tasting compounds in stevia

I did find some additional research evidence that gave me pause with stevia:

1. The metabolism of stevia may or may not create an epoxide intermediate in the gut. One study found the presence of this epoxide, two others didn’t, but it needs to be further investigated because epoxides are reactive species that can damage DNA. Damaging DNA is generally not good.

2. In cell culture assays, stevioside was found to be mutagenic to bacterial cells – in other words, it caused an increased number of DNA mutations. Mutagenicity is suggestive of possible carcinogenesis. Needs further study. Please see pages 9 and 10 of the attached pdf at the end of this article for more detail if you’re interested, under the heading Genotoxic Effects.

3. Stevioside causes DNA breakage in blood, spleen, liver, and brain cells in rats (Nunes et al., 2007). This concerns me even more, as we’re talking mammalian cells now, not bacteria.

Now, to present a balanced argument, other studies have found NO effects when studying stevia and it’s components. A lot more studies have to be done to clarify the inconsistencies. In my opinion, there simply isn’t enough data, particularly long-term consumption data (there is none) for me to put my trust in stevia. It is simply too new, and I would trust it more if in ten or twenty years from now there is a greater library of safety research on stevia, involving multiple mammalian species, human trials and detailed metabolism of the compounds have been elucidated.

Now, should you be concerned if you are using stevia in your food or drinks? Probably not, unless you’re mainlining it. The doses at which these things are tested is quite high, so if you use it in one food item per day, I’d say the risk isn’t severe. I wouldn’t use it multiple foods per day though. Stay under 4 mg/kg.

Personally, I am most confident in the safety of aspartame, given that it has the longest clean track record of research, and every researcher and their mother has tried to find ill health effects of it. The composition of it makes biological sense to me: two amino acids and a methyl group. I can visualize the metabolism, breakdown and excretion of the components. It’s not a mystery to me, and I don’t get anywhere NEAR the ridiculously high ADI for it.

Splenda – I feel like it’s somewhere in the middle. It doesn’t have as much of a depth of safety studies as aspartame, but it’s got more than stevia. The molecular structure of sucralose ought to be minimally absorbed from the gut (since it isn’t recognized by glucose uptake mechanisms) which logically helps support that it is unlikely to cause systemic effects, since probably very little of it reaches the bloodstream, brain, etc. What does concern me (and lead me to limit my use of it) is the possible effects on gut flora and cells lining the intestine, as they are subjected to the highest concentration of the compound.

Okay this is already so long that no one else is reading I suppose……

Personally, I will continue my tasting of the free stevia samples I received just to check them all out, but I’m too cautious of it to buy it and use it long term. Just my personal choice. You do what feels (and tastes) good for you.

For more detailed research findings on what led me to my choice, see this toxicology report.

Before you send me hate mail … or an internet rumor that sucralose and aspartame cause lupus/baldness/cancer/scurvy/herpes/heart disease/ADD ….  or tell me how your Aunt Sophie stopped drinking diet soda and her poodle Elvis came back to life… realize that I have no problem with you eating whatever you want and avoiding whatever you want. Respectful disagreement and discussion is welcomed, factless anecdotes or emotionally charged diatribes are not. Don’t get into a tizzy.

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  • kerragh May 24, 2014, 6:57 am

    Thanks for the informative post, especially the final disclaimer. Sometimes it is best to “agree to disagree”. It is impossible to please everyone, but putting the information out there is always appreciated.

  • Georgie July 12, 2013, 1:15 pm

    Thank you Anna, that compliment was deeply appreciated. 🙂

  • Anna July 11, 2013, 10:59 pm

    Thanks so much for this info – I really love how you just simply lay everything out, all logical and organized, and it’s obvious that you’ve do e so much careful research. Your opinions and findings were extremely helpful!

  • Georgie June 5, 2013, 12:04 pm

    Linda, I wouldn’t be concerned about the stevia in your coffee, but finding ways to successfully pare out the sugary snack foods and ice cream would surely be a great step toward better health and wellbeing. Nobody likes feeling controlled by cravings!

  • Linda June 4, 2013, 6:00 pm

    George … I have a sweet tooth and I am Diabetic II. I use a heaping tablespoon of “Stevia in the Raw” for a 4 – 6 officially measured cups of coffee per day.

    Is this too much? Yes, it has a tendency to make we want sugar in ice cream and some snack foods, and that of course, is the demon I deal with daily,… and sometimes lose (not weight, I’m afraid)

    P.S. How can companies get away with false advertising on their packaging?
    All they bribing the FDA?!

  • Sara July 9, 2011, 2:29 pm

    Hi Georgie,

    This is an informative post with information I had not seen before. Thanks for sharing what you’ve learned! As I am an avid stevia user, it’s good for me to know what concerns are out there with it. I’ve sure paused as I’ve reached for the stevia in the past couple days since I first read this.

    Have you ever heard of or read the book Excitotoxins: The Taste that Kills by Russell Blaylock, MD? I’m wondering whether you think the issues it raises with MSG, nutrasweet, etc. are valid. When I read it a year or so ago, it convinced me to break my 22 year addiction to diet soft drinks.

    In the end, the truth is, we’re all better off eating whole foods with as few additives as possible. I sure do like a bit of sweet without the calories of sugar, though. 😉 Wish it didn’t seem so tricky to figure out the safest product.

  • Alyson @ Nourished Fitness July 4, 2011, 1:27 pm

    Oh great post, great info.. interesting, and a lot I didn’t know. Stevia has been my sweetener of choice for the last couple years, and although I always get the “pure” extract and not packets.. it really just feels like ‘pick your poison’ at this point. Thanks!

  • admin July 4, 2011, 10:44 am

    I quite like xylitol, and have been using it a bit as well. I like to mix it with Splenda in baked goods, seems to give a more sugar-like taste without any aftertaste than splenda alone. I like the “cooling” sensation of it as well, esp in cold/refrigerated things like cheesecake bars, smoothies, or in peppermint-flavored anything.

    I will have to do more research on the metabolism etc of it, but from what I know it’s pretty benign.

  • Phaedra July 4, 2011, 8:56 am

    Thanks for a great article Georgie. I use stevia in my coffee (1 packet) and then use Splenda when I’m baking (which is mostly your goodies, he he he). I don’t think I use enough stevia to worry but I’m definitely a bit more wary!
    What are your thoughts on xylitol? I found some at the grocery store and have yet to try it.

  • debby July 4, 2011, 7:47 am

    Great info as always, Georgie! I was just telling another blogger to check you out for your information on artificial sweeteners, and here you have a whole article on it!

    My favorite part was the last paragraph LOL!

  • Diana Johnson July 4, 2011, 5:19 am

    Hi Georgie! This is a great article, and you are awesome! I also LOVE your comment on the bottom! Have a great day!

  • danielle July 4, 2011, 5:01 am

    I think we all owe you a ‘thanks!’ for digging through so much research on a topic so many of us are curious about! Great post. I personally am much happier since giving up all artificial sweeteners, and am working on eliminating ‘real’ sugar now too. Real or fake, I just dont think our bodies were made to consume it in the high quantities that mark many american diets…well at least mine! Thanks for taking the time to write such an informative, balanced post.

  • MAD July 4, 2011, 3:20 am

    Solid compiling of research of what is knonw and NOT known Georgie – Thanks! So for the baking, which seem to do well for recipes or does it matter? BTW – I could not open the toxicology report. And I loved your disclaimers as well!

  • admin July 3, 2011, 9:12 pm

    Nicole, Thank you! That means so much to me. I think what’s critical for RDs and bloggers is to present one’s opinion, give some evidence to how you came to that conclusion, and leave it up to the reader. I don’t push my points, because I hate when I feel someone is coercing me to do as they do or I’m WRONG.

    I hear you on not wanting to argue. Surprisingly, I have been pretty spared from rude comments but that delete button is always there. 😉

  • admin July 3, 2011, 9:09 pm

    Thanks Monica! I appreciate you reading the whole thing haha! I’m still following your cooking and CSA adventures!

  • admin July 3, 2011, 9:09 pm

    Thanks so much Kalyn – I stand with your MD. And I agree with you that any of the above work better for me than sugar!

  • Nicole, RD July 3, 2011, 5:43 pm

    Hands down the best post I’ve read in a long time. And kudos to you for, like you said, sharing with caution. I have shied away from opposing popular opinion because, quite frankly, I don’t like to argue, and someone out there is always going to be smarter than me and know more about subject than me and in turn, blow up my email or leave a hateful, unnecessary comment. Like yourself, I use a little bit of them all. I do prefer the taste of stevia the best, so I’ve leaned towards that route. But as you discussed, I use about 1 serving a day, or less – a level I feel very safe consuming. The one other thing I really do enjoy about stevia products is the liquid format. It really does mix well in beverages and since that’s my primary use, it’s a perk for me. Excellent, excellent post! Especially that disclaimer at the bottom 😉

  • Monica July 3, 2011, 3:14 pm

    Hi Georgie! I just wanted to say I appreciate how you present both sides of an issue. It doesn’t change my personal opinion (I’ll continue to avoid artificial sweeteners) but it is refreshing to be given balanced information. Also, I did read all the way to the end, and I love your note at the bottom…

  • Kalyn July 3, 2011, 11:53 am

    I’m fascinated by this. I have asked my doctor several times about aspartame, since I am a diet soda drinker and been reassured over and over that it doesn’t cause cancer. I don’t use a lot of Splenda, but I do bake with it once in a while. For me, all these things are better than sugar, which sends me off on an eating binge if I’m not careful!