Does Xylitol Cause Tumors?

You've probably heard about the concerns about xylitol causing digestive upset, but have you heard about xylitol possiby causing tumors?

It's true–some have claimed this. Scary stuff for sure.

It's frightening when something you eat and enjoy (especially when you think it's healthy) gets demonized. It's enough to make you want to throw in the towel on healthy eating.

Like when I heard about stevia causing all sorts of issues and needed to dig in to find out about stevia safety.

Or when a study came out connecting erythritol and heart disease.

Well, here's another one.

Since switching our family over to low carb sweeteners, I've been concerned on and off about their safety.

I'm a natural-minded gal and really want my and my family's food to be as clean as possible, but when battling candida, you do what you have to do.

Now we don't use saccharin or Nutrasweet, but we do use stevia and xylitol and a few others, and since I have a bit of a sweet tooth, I started looking into the safety of those sweeteners to figure out what the truth is about them and their impact on our health.

There are many low carb sweeteners on the market, but many of them come with challenges, with quite a few of those being concerns about how safe they are.

Now, some of the concerns are valid.

But some, I think are not.

For this post, we'll mainly stick to the concerns about whether or not xylitol causes tumors, however, and hopefully we'll deal with other sweetener concerns later.

Sweeteners I Don't Use:

saccharin (however there is now evidence that it actually have some health benefits!)
sucralose (Splenda)
acesulfame potassium
Nutrasweet
agave
honey (except for as a natural allergy remedy)
refined sugar

Sweeteners I Use:

stevia
xylitol
erythritol (in lesser proportions)
allulose
coconut sugar (occasionally)
raw honey
jerusalem artichoke (haven't done much with this)
lo han guo (I don't use this often either)
sucanat (very occasionally)

Does Xylitol Cause Tumors?

One of the concerns I have heard several times is that xylitol has been found to cause tumors.

“There is some concern that extremely high doses for long periods of time (more than three years) can cause tumors.”

“Although some animal studies have shown tumor growth resulting from high doses of xylitol over long periods, more research is needed”

I spent literally hours on this. At first, I found very little information to back any of this up.

Just dead ends, lack of source citations, and articles missing from the internet.

Finally, however, I found some helpful information.

Before looking at the “evidence” that xylitol causes tumors, let's look at this first.

Evidence that Xylitol Does NOT Cause Tumors

In this study by Sato, Wang, and van Eys, lab rats with various pre-existing liver tumors received a 10% IV solution of Xylitol at the rate of 2 g per kg body weight. The researchers found that hepatocellular carcinoma was markedly deficient in the ability to synthesize acid-insoluble glycogen and glycoprotein from xylitol.

What this means is that researchers found that (on pre-existing tumors) the xylitol caused significantly less harm than ordinary table sugar. Note that the tumors were pre-existing ones. So they were not caused by xylitol. However, in comparison to sugar, the tumors didn't grow as fast.

Evidence that Xylitol Causes Tumors

The only sources that I have seen citing this issue of xylitol are the following:

1. The Natural Medicines Database

To quote this source, xylitol is

“POSSIBLY UNSAFE …when used orally in very high doses, long-term. There is some concern that very high doses for extended periods of use can induce tumor growth (6815,6820). However, this effect has not yet been demonstrated in humans.”

with the following references given.

6815: Lee B, Sue D. Xylitol for prevention of dental caries. DICP 1989;23:691-2.

6820: Crapo PA. Use of alternative sweeteners in diabetic diet. Diabetes Care 1988;11:174-82.”

I couldn't locate the source of the first reference.  There are references to it on the internet, but I can't find the publication (if it exists) itself.

The second one is a 1988 review by Phillis Crapo, RD entitled, “Use of Alternative Sweeteners in Diabetic Diet”

In 1988 a registered dietician (RD), Phillis Crapo, wrote a scholarly review of many-many articles titled, “Use of alternative sweeteners in diabetic diet”. In her review she made the following statement (that WebMD probably refers to):

“However, chronic intake of xylitol in animals has been shown to be associated with tumor induction and other pathology. Consequently, use of xylitol is currently curtailed in the United States, and no recommendation concerning its use can be made.” p. 177

There is, however, no source referred to that supports this statement.

Of course, looking at this claim, one really needs to ask the following questions about Ms. Crapo's statement:

What does “chronic” mean?

What amount of xylitol is being eaten?

What are the “other pathology(ies)” that she refers to?

What animals were involved in this?

I assume that this is the “source” the WebMD and RxList are referring to.

Also, it is important to keep in mind that WebMD and RxList cross-syndicate, so they may be using each other as a source.

However, this second source is interesting.

2.  Mice Bladder Tumors and Xylitol

In summary, male mice eating a diet consisting of 10-20% xylitol developed bladder stones.

“Some of the mice that developed bladder stones also had bladder inflammation and benign and malignant tumors. Female mice developed no unusual symptoms, and neither did male mice fed xylitol as 2% of their diet.”

Things to note about this study:

Only the male mice had issues with the xylitol.  Why is that?

No similar effects were seen in the 2, 10, and 20% females, 2%
xylitol males, or the 20% sucrose group.

Important to note here is that we are seeing a correlation about bladder stones.  And “some” of the mice had benign and malignant tumors.”

Also of note is the fact that female mice showed an increase in tumors when fed a diet comprised of 20% sucrose.

Questions I'm Asking:

How many is “some”?  Is that 1 or 2 mice?  or 3?  Is that really a correlation?

Why was this affect only on the male mice and not the female?

We are also not mice. Xylitol causes a lot of problems for dogs, but humans can eat it. Would xylitol have the same effect on humans as on mice?

How much xylitol were the mice being fed? If you translate the amounts of xylitol used in the study to a human diet, 200 – 400 calories out of a 2,000 calorie diet would need to be xylitol (that's 21 – 42  teaspoons, or 7 – 14 tablespoons).

That's a lot of xylitol, and it's being eaten for a long time.

So this is equivalent to an adult eating about 3/4 of a cup of xylitol, every day, for 16 weeks straight.

I know that I for sure don't do that — even with my sweet tooth.

Additionally, if you read all of the research, at 20% of diet, there did not appear to be an increase in tumors in rats, rabbits or dogs (this is an interesting study since dogs are not supposed to do well with xylitol at all), however other effects are noted in some cases.

So — as with many things, I think we have to make our own decisions about this.

Does xylitol cause tumors?

Or is it just a false scare tactic?

Conclusion

My stance on sweeteners is this.

Everything should be in moderation. It's not a good idea to eat too much meat, too much fruit, too many grain, too much salt…even too much water can damage your kidneys.

In our family, we primarily use pure stevia extract as our sweetener of choice. There is some concern in various articles about stevia (that it caused infertility, DNA damage, hypoglycemia, and more), but I did a bunch of research on the safety of stevia and think that it is, in fact, very safe.

If possible, we would use natural honey or coconut sugar perhaps as our main sweetener, but the glycemic load is too much for us, and since we suffer from candida or other carbohydrate intolerance issues, we simply can't.

We blend sweeteners.

For example, for any sweet recipe, I try to break it up into equivalent sweetness amounts of stevia, xylitol, and erythritol, or some combination of those.  In fact, doing this even helps those who don't like stevia to really like the taste of stevia.

If any one sweetener turns out to be a problem, then automatically we've diluted our exposure.

You can blend up your own mix, or you can buy the sweeteners pre-blended, like this brand.

Also, we try to move away from treats and towards more veggies and other whole foods — but I still have a sweet tooth I like having treats.

So–does xylitol cause tumors?

It seems to do so in male mice eating a 20% of diet fed for 16 weeks (that's a LOT of xylitol!), but in female mice it appears not to, and in other animals it appears not to.

But for me, I am still going to eat xylitol.

I'm not worried about it.

I do, however, recommend using xylitol derived from birch (if possible), as opposed to corn, or at least one that is derived from non-GMO corn.

This is one brand that I like and use.

How about you?  Do you use xylitol?