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3 Feb

Do Artificial Sweeteners Cause an Insulin Spike?

The notion that artificial sweeteners (and sweet tastes in general) might produce an insulin response is one of those murky memes that winds itself around the blogs, but it’s never stated one way or the other with any sort of confidence. I briefly mentioned the possibility of non-caloric sweeteners influencing satiety hormones in last week’s diet soda post, and a number of you guys mentioned the same thing. Still, I’ve never seen unequivocal evidence that this is the case.

This whole idea first came to my attention some time ago when my dog Buddha got into a bottle of “alternative sleep assists” which contained, among other things, 5 HTP (version of l-tryptophan) and xylitol (sugar alcohol). Long story short, dogs can’t take xylitol because it causes a spike in insulin, which then severely depletes blood glucose. Buddha got past this with a trip to the vet’s at 10:30 Sunday night (thanks, Dr. Dean). But it occurred to me that the same effect might be seen in humans, which is why I pose the question today…

Do artificial sweeteners induce insulin secretion (perhaps via cephalic phase insulin release, which is sort of the body’s preemptive strike against foods that will require insulin to deal with)?

One of the reasons a definitive answer is rarely given is that the question is improperly framed. Artificial sweeteners is not a monolithic entity. There are multiple types of sweeteners, all of them chemically distinct from each other. A more useful question would be “What effect does [specific artificial sweetener goes here] have on insulin?” So let’s go around the circle and ask.

Does aspartame (aka Equal and Nutrasweet) affect insulin?

Aspartame is pretty gross stuff, what with its awful taste and hordes of people who get terrible reactions from consuming it, but that’s not what we’re interested in today. Luckily, there is a good amount of research explaining what, if any, effect aspartame has on insulin secretion.

One study found that protein produced a significant insulin response, while aspartame had no effect on insulin levels.

Another also found that aspartame had no effect on the insulin response in humans, whether alone or combined with carbohydrates.

Another earlier study (full PDF) examined the effects of aspartame on prolactin, cortisol, growth hormone, insulin, and blood glucose levels and found it had none. The authors used the same amount of aspartame you’d find in a standard artificially-sweetened drink but were unable to record any significant hormonal alterations.

A study of forty-eight healthy volunteers found no evidence that aspartame has an effect on insulin levels.

Overall, the evidence seems to suggest little, if any, effect on insulin secretion as a result of tasting or consuming aspartame.

Does saccharin (aka Sweet’N Low) affect insulin?

Although saccharin has lingered in obscurity and consumer banishment (who ever really picks Sweet ‘n’ Low, anyway?) for most of the last couple decades (until recently when the EPA dubbed it safe for human consumption), there is some research on its effects on insulin.

In one study, fasted human subjects swished around eight different taste solutions for 45 seconds, and then spat them out. No swallowing. Only the sucrose and saccharin solutions activated a cephalic phase insulin release.

On the other hand, another study using humans found the opposite: swishing and spitting sweet solutions (even caloric ones using sucrose) did not elicit CPIR, while another study found that neither saccharin nor aspartame influenced insulin secretion in both fasted diabetics and non-diabetics (although aspartame-fed subjects had slightly higher insulin levels than the control and saccharin groups, this was physiologically irrelevant given the steady blood glucose levels).

The evidence for saccharin’s effect on insulin is mixed, but either way, it doesn’t appear to have too big of an impact in real world terms.

Does acesulfame K (aka Sunett and Sweet One) affect insulin?

In one study, researchers found that direct transfusions of acesulfame K increased insulin secretion in rats in a dose-dependent fashion. The same researchers performed an in vitro study, subjecting isolated rat pancreatic islets to acesulfame K solutions, and found that the artificial sweetener was an independent actor on insulin secretion. Both indicate that there is some effect, but it’s difficult to draw any conclusions from in vitro rat studies using isolated pancreatic cells or in vivo rat studies using direct transfusions of sweeteners (as opposed to oral dosing).

Another study using isolated pancreatic cells found that only those artificial sweeteners with a bitter aftertaste (acesulfame K, saccharin, stevia, and cyclamate) augmented the insulin response in the presence of glucose. Aspartame, which does not have a bitter aftertaste, did not affect insulin. Note, though, that this was an in vitro study using isolated cells and that the presence of glucose was a prerequisite for insulin secretion. Of course, dieters slurping down artificial sweeteners do it during meals, most of which tend to feature large amounts of glucose.

Acesulfame K appears to affect insulin levels, although this effect has only been shown in contrived settings – either in the presence of glucose in isolated cells (in vitro), in isolated cells in without glucose (in vitro), or by direct transfusions without the presence of glucose (in vivo). We haven’t seen people orally taking acesulfame K in a fasted state and having an insulin response. Yet.

Does sucralose (aka Splenda) affect insulin?

Sucralose activates the sweet receptors in taste buds, and some in vitro studies have shown that sucralose can stimulate the release of incretin hormones, which increase the secretion of insulin, via the sweet taste receptors in enteroendocrine cells (located in the gut). An in vivo study of sucralose infusions into the gut, however, showed that it does not stimulate the incretin hormones GLP-1 or GIP, does not release insulin, and does not slow gastric emptying.

Another in vivo study, this time using healthy human subjects, got similar results: oral dosing of sucralose did not induce a cephalic insulin response, nor did it affect GLP-1. Not even appetite was affected.

The commercial version of sucralose, Splenda, is cut with dextrose as a bulking agent. Dextrose is essentially glucose, which certainly elicits an insulin response, so there’s definitely the potential for a slight insulin response to Splenda, but there’s not much if any evidence that sucralose has an independent in vivo effect on insulin.

Recently, a review of in vivo studies concluded that “low-energy sweeteners” do not have any of the effects on insulin, appetite, or blood glucose predicted by “in vitro, in situ, or knockout studies in animals.” As far as the clinical studies go, I think I’d have to agree. Am I going to use the stuff? No; there are other potential negative effects to artificial sweetener usage, including gut flora disturbances, the promotion of psychological dependencies on sweets, and long term safety issues, but I think it’s important to be clear on where the science lies. So far as I can tell, according to the literature there isn’t an appreciable insulin effect from most sweeteners.

Still, some people anecdotally report an effect. As Jimmy Moore says, “The bottom line is to check your own blood sugar response and see how it impacts YOU.” Word. If you need to know (and most people don’t), testing yourself would be the way to do it.

Let me know if I’ve missed something, or come up short in my analysis. There’s a lot of stuff out there and it’s possible that I’ve overlooked something. And as always, I’d love to hear about your personal experiences with artificial sweeteners, especially regarding their effect on your weight loss/gain, insulin, appetite, and dietary success/failure. Let me know in the comment section!

P.S. If you’re new here and aren’t sure what all the fuss over insulin is about start here: The Definitive Guide to Insulin, Blood Sugar and Type 2 Diabetes (and you’ll understand it)

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Mark any comments on whey low? In their info they state it causes no insulin spikes.

    Milliann Johnson wrote on February 3rd, 2011
  2. Since I gave up artificial sweeteners my goiter has gotten much better.

    rob wrote on February 3rd, 2011
  3. I gave up artificial sweeteners almost 6 years ago in response to side effects-like headaches, dizziness, and even panic attacks- that they were causing me. Granted I was having a fairly large dose of them, along the lines of 4-5 20 oz diet sodas a day. All symptoms stopped within a week of cutting all artificial sweeteners.

    I am also suspicious of stevia, I wish there was more info on what that does to a body, or if the body anticipates something sweet and reacts as it does with articial ones.

    James wrote on February 3rd, 2011
  4. I use xylitol in the only sweetened food I have which is my daily coffee. 2 cups per day with a spoonful of xylitol in each. I don’t do primal baked goodies and find fruit (which I eat rarely) to be enough to settle any desire for sweet food.
    It doesn’t induce cravings and I have it in such small amounts that I really don’t worry about it.

    Emma wrote on February 3rd, 2011
  5. Hey Mark, I’m just wondering about the Purdue University study that came out a couple of years ago linking artificial sweeteners to weight gain. Where would that fit into all of this? Are you thinking that it’s not insulin secretion, and rather another mechanism that could be behind this weight gain, such as psychological dependence/lessened insulin response to other sugars/??? Just curious as to your thoughts. :)

    Matthew Myers wrote on February 3rd, 2011
    • As Dr. Eades states time and again, correlation is not causation, and there was no hard evidence presented, only weasel words such as “suggests,” “suspect,” “might,” etc. And the study was done on rats. Another one using a few fat people relied on self-reporting. More than likely, they were consuming loads of refined carbs along with the diet soda.

      Katy wrote on February 4th, 2011
  6. Seems to be a lot of Primal folks out there who still dable in artificial sweeteners. I can understand the appeal as well as the intense cravings, however I would like to offer encouragement, as others have, to just try to cut out all of the sweet stuff. Give it a few weeks and see what happens.

    The only sweetened food I consume, now that I am Primal, is 85% cocoa or higher dark chocolate. Chocolate has always been my weakness. Just out of curiosity, I helped myself to a Hershey’s milk chocolate kiss at work. I almost had to spit it out it tasted so disgusting to me. My taste for sweet has become so sensitive after only about 5 months of living Primal that I not only don’t crave sweet, I don’t like it.

    And as a few others have pointed out, I can taste and appreciate other flavors more now.

    I know I’ve never had as strong as sweet tooth as some but I’ve never been disgusted by sweets before now. I have to think that with a little hard work and a system of alternative rewards in place, most people could experience a similar effect.

    fritzy wrote on February 3rd, 2011
    • @fritzy. Agreed. I no longer like the taste of those sweet things I used to like. The only sweetener I have is stevia, and I only have that in my morning coffee and in my whey protein shakes (and even then in only very small quantities). I tried a piece of milk chocolate a few months back and had the same sensation, not only because of the sweetness but also because of the milk.

      Kitty wrote on February 3rd, 2011
  7. I had a feeling it was going to turn out this way and I’m ashamed I didn’t do my own homework on the subject.

    I had been saying for a while that if they *have* found an association between artificial sweeteners and insulin spikes, either it was going to be that cephalic response thing, or it was going to be from the bulking agent, which is usually either dextrose or maltodextrin or both–and both are sugars. Nice to know someone bothered conducting studies that controlled for the bulking agents.

    Dana wrote on February 3rd, 2011
  8. By the way, I don’t have trouble with artificial sweeteners in the sense of them making me eat badly. (I don’t think aspartame agrees with me, and I hate the taste of saccharin, though.) But I usually favor savory snacks over sweet, and only want a sweet treat every now and again. I do want my coffee sweetened, but I have maybe two cups a day. (Kicking caffeine is on the agenda, I just haven’t gotten around to it yet. Kind of nervous at the prospect, actually, as I suffer from various types of headaches.)

    For the record, I am disgusted by sugar-sweetened foods now. They are too sweet for me *even though I am still using Splenda.* Although Splenda does taste very close to sugar because it’s really nothing more than a chlorinated sucrose molecule, it apparently doesn’t taste close enough. So it’s not a sure thing that you won’t lose your taste for sugar just because you are still tasting things that are sweet.

    Also, I have long had an appreciation for herbs and spices, and I was eating brown rice before it became cool and trendy, because I liked that taste better than the white rice as well. I have a fairly sharp sense of taste, unblunted by my liking for sweetened coffee.

    So it’s not a sure thing that X behavior will produce Y result or that everybody who likes sweet stuff has some kind of eating disorder. I don’t believe *all* things are OK in moderation, but occasional sweetness *is* part of our evolutionary experience. So unless it’s really messing you up to taste something sweet now and again, don’t guilt-trip yourself to death about it.

    Dana wrote on February 3rd, 2011
  9. Exactly the kind of thing I’ve been wanting to read! Thank You!

    Scott wrote on February 3rd, 2011
  10. Back when I was drinking huge amounts of iced tea and sweetening it with Sweet N Low, I noticed that I got hungry all over again after drinking it, even if I’d just eaten half a chicken for dinner.

    I am not sure if other artificial sweeteners did this to me, because I don’t remember testing them this way.

    I have at times gotten a headache when using Equal, so I don’t use anything else but either saccharin or stevia.

    I can get away with a little bit of iced tea and pure saccharin (Necta-Sweet tablets) but note that Sweet N Low (and lots of the others) are “cut” with maltodextrin, dextrose, and other “nutritive” sweeteners etc.

    Sugar alcohols can give humans diarrhea. I once bought and ate some Girl Scout cookies with xylitol in them, and it was just like using Ex-Lax and about as prompt.

    I like stevia. I like the taste of the white powder better than green powder, but I just ordered some green powder to get used to, and also some tablets for iced tea when I’m out and about.

    I think that for some people, caffeine can affect blood sugar and insulin levels also.

    The problem for me, and for other people, is that if you use enough of any kind of sweetener, you risk stirring up sweet cravings again.

    Pam wrote on February 3rd, 2011
    • If you buy high quality xylitol, it does not induce diarrhea. I had the same problem with the cheap xylitol, ie Now Brand at $9 a bag, but then I was introduced to The Ultimate Sweetener Brand, $18, and it never bothers me.

      I use Stevia as well.

      Gena wrote on February 4th, 2011
  11. I think in general artificial food is non-beneficial and artificial sweeteners are linked to cancer. that said, I do chew sugarless gum. I am VERY sensitive to sugars and carbs but I have no apparent and immediate impacts from gum.

    DThalman wrote on February 3rd, 2011
  12. I love coffee and don’t use sugar but I can’t go so far as to drink it black. I always choose sweet and low because saccharine passes through your body unchanged while Equal breaks down into 3 different compounds. There is no evidence that these 3 compounds hurt you but not enough study has been done yet.

    John wrote on February 4th, 2011
  13. In light of how most research is conducted today, you have faith in a VA/Nutrasweet sponsored study? Really? I’d bet dollars to artificially sweetened donuts that a real researcher with no conflict of interest would prove otherwise.

    Brett wrote on February 4th, 2011
  14. This was a great article.

    I bet the first few days without artificial sweetness are tough, but once you’re over that first hump it gets easier.

    I might give it a try. BUT, I really like protein shakes. I know I know, Grok never had access to shakes. But they’re really convenient for an on-the-go gym junkie. Maybe this could be my ONLY source of sweetness.

    Danielle wrote on February 4th, 2011
  15. if it tastes sweet, I will overeat.

    I’ve tried them all, and my belief is that if you have hyperinsulinemia, meaning reactive insulin, sweets from any source will trigger insulin.

    digby wrote on February 4th, 2011
  16. I’ve been interested in this question so thank you for this article.

    It seems to me, however, that in the big picture, whether or not we get even a small insulin response from artificial sweeteners doesn’t really matter. That is because protein intake has shown to cause insulin response, sometimes a very large response in the case of whey for example. So whether or not you cut out all sources of sugar or sweeteners you still are getting ample insulin response on a paleo diet.

    Is this line of thinking correct? If not, please correct me, as this has always been a point of confusion for me regarding avoiding sugars because of the insulin response. Thanks.

    Dave wrote on February 4th, 2011
    • dave…i’m with you on that. i don’t think insulin is a bad guy at all. an insulin spike isn’t a dangerous thing either (in healthy people) …therefore…insulin isn’t dangerous…we actually need it of course (diabetics). what we don’t want to do…is damage our metabolism so that the insulin doesn’t do its job. that’s the danger. you’re right, protein and dairy have considerable insulin responses…but that doesn’t make them unhealthy. just like it seems some primative cultures could eat a lot of stachy tubers (glucose) and avoid western disease. they would obviously have had an insulin response but a healthy one. the things that damage this are fructose, n-6 veg/seed oils, wheat. i’ve read some evidence that insulin is more than just for shuttling glucose into cells, that it also acts as a brake to stop your liver from producing ketones or releasing stored glycogen in the presence of glucose. this makes sense if you think about ketoacidosis and can even help explain hyperglycemia in type 2 diabetics. (blood sugar is high and not only is it not being lowered by absorption to cells but your own body is keeping it higher by still releasing glycogen as it hasn’t gotten the message). i’m like mark…i don’t eat fake sugars…but that would be the case regardless of what the insulin response is. i’m curious to hear what others have to say on this…as i’ve been trying to piece this theory together in my mind for some time. i believe mark has touched on some of these aspects before (like the insulin response to dairy).

      brandon keatley wrote on February 4th, 2011
      • the healthy skeptic has just written a good piece suggesting that avoiding disease is about more than just keeping one macronutrient low etc. that it’s certain types of each macronutrient that damage your metabolism (and insulin response). similar information can be found in various places here on mda of course.

        that said…there are probably still benefits to low carb for your daily life than just whether or not “safe” carbs can lead you to disease…at least in my mind.

        brandon keatley wrote on February 4th, 2011
  17. In her book Kiss Your Dentist Goodbye Dr. Ellie Phillips discusses the research supporting protective effect of xylitol against caries.

    Cayte wrote on February 4th, 2011
    • I managed to reverse a cavity using Dr. Ellie’s simple, inexpensive protocol – my dentist called it “magic”!

      happy1 wrote on February 5th, 2011
  18. I simply cannot eat sweets of any kind; they tend to trigger a binge. Except for those small amount of carbs found in raw foods such as vegetables, I simply must avoid all carbs with emphasis on sweet flavors. I even avoid fruit.

    Phocion Timon wrote on February 5th, 2011
  19. In 2009, I was on an extended backpacking trip with my husband. I brought some of those electrolyte hydration tablets that you add to water. They are sweetened with sorbitol and acesulfame K. After drinking part of my water with the tablet, my blood sugar crashed horribly. My legs were so shaky that I had to sit down.

    My husband, who isn’t afraid of artificial sweeteners, took the rest of my water and the same thing happened to him.

    Never again.

    Naomi wrote on February 5th, 2011
  20. I have a very serious Coke Zero addiction. I drink about 7 a day. I know it’s bad for me to have that much and the caffiene is probably just as bad for me as the chemicals. But whatevs, I am cool with the risks for the enjoyment of drinking Coke Zero.

    I switched to a lowcarb diet four months ago and have lost 30 pounds effortlessly. I have only 10 more pounds to go and I’ll be back to my size 4 high school weight.

    I would say that if I can drink 7 Coke Zeros a day and still loose weight it’s probably not a big deal insulin wise.

    Also I tried to give it up fearly it was causing an insulin response and I gained 3 pounds during the time I was not drinking Coke Zero and lost the three pounds immediately after starting to drink it again. This may be related to the stress of withdrawal though.

    Katie wrote on February 5th, 2011
  21. After seeing the ‘Sweet Misery’ documentary, no need to even consider aspartame anymore.

    What would be interesting is, to compare these 0 calorie sweeteners:

    Stevia (SweetLeaf, Skoopz, etc)

    Chicory Root / Vitamin C
    ( )

    Whey Sugar (

    Monk Fruit / luo han guo extract ( )

    Sugar Alcohols ( Xylitol, Erythritol , etc) (, etc)

    and maybe even fructose, honey, and agave, all of which have calories, but are said to not have much an effect on blood sugar.

    ben wrote on February 5th, 2011
  22. I was invited to a lunch meeting with few professors from Sweden and Iceland the other day. They showed me results from studies they had done on artificial sweeteners and even though you keep reading blogs from people saying they are going to spike your insulin, give you cancer and what not their results could not confirm any of this. They even told me about a German study on aspartame where they tried to induce cancer in rats over 12 months with dosage so high that a person could never consume the same amount in 9 months the results… cancer, no problems, nothing!

    I’m just one of those people that I don’t believe the hype, show me the studies and I’ll change my mind until then, artificial sweeteners are not going to kill anyone 😉

    Lee Christmas wrote on February 6th, 2011
  23. ugh… if it’s “artificial”, simulated or whatever, I just don’t eat it. If I want sugar, I use sucanat. I put some in my coffee. I use honey, molasses, or maple syrup in some cooking applications. Once in a while stevia in a beverage. That’s all. I’ve used tom’s toothpast for years, so I know how sweetened all the others are (yuk!)

    Peggy wrote on February 6th, 2011
  24. Mark would having one diet coke can a day be a problem? if this was the only soft drink i had…

    Im thinking about going Primal but im still not sure if i can do it. I have everything low caloric, including yogurt, cordial, butter etc.. im worried this is my problem with staying a big girl.. i have always been a big girl since i was little. im looking into my hormones and have always been insomniac, I seem to do well if i count calories but its a lot of work to concentrate on. But the weight comes back as i do like my chocolate and abit of a drink. i know i sound like i want something without doing it properly. i believe you only live once so you should enjoy it.. however i do want to be healthy. Im so confused on what is wrong & right … between carbs, low calories, sweeteners & proper fat.. im LOST

    Sharn wrote on February 9th, 2011
  25. I read once that just thinking about food would bring a response.I use equal and see no effects from it.I think people just have to listen to their body and adjust.I think all the posts about sodas,well i think cokes and such encourage cancer by being acidic.I still have a diet coke once in a while as a treat.(you must remember the old leaving a penny in coke and see it slowly disolve with time thing)soda pop just isnt good for you.regular non diet soda has just an incredible amount of sugar in it.

    Ron wrote on February 9th, 2011
  26. The responses here could make a very nice study on why people believe anecdotal research vs real studies when it suits their belief structure. Thanks for trying Mark!

    Lovelessk wrote on August 20th, 2011
  27. So I’m going to have to give up my diet coke-a-day addiction (and crystal light addiction)… Ok, but what is the best choice to add to my morning coffee and afternoon tea as I try to cut it down to less and less until I acquire a taste for no sweetener at all?

    Cindi wrote on September 13th, 2011
  28. I didn’t see alot, if any, DIABETICS posting here.
    I am a Diabetic, Insulin-dependent, and I use SPLENDA daily. I can tell you that it does not effect my Insulin levels and I do glucose finger-sticks daily also……
    For me, SPLENDA, is he best sweetner on the market!

    Patrick wrote on December 31st, 2011

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