Question About Xylitol

Dear Dr. Phillips,

As a chemist, I have long questioned the basis for putting fluoride into public water supplies.  On the other hand, I think that there is ample evidence to support topical applications of fluoride directly on the teeth. I am wondering if the same dichotomy would apply to the use of xylitol.  If I understand the mechanism by which xylitol does its magic, it is that a rinse with a xylitol solution lowers the concentration of most sugars in the mouth while increasing the concentration of xylitol.  

The harmful mouth bacteria can not metabolize xylitol and therefore their population decreases.  Does this same effect take place when xylitol is ingested?  For example, I started out to achieve your published goal of consuming 6-10 gm/day of xylitol by adding a teaspoon to my morning cereal.  For the remainder, I used a pair of Spry mints after each meal or encounter with sucrose.  As has been published back in the ’70’s when xylitol first appeared on the scene, loose bowels followed.

The looseness of bowels must be the result of xylitol having an effect on the bacteria in the intestines that is similar to its effect on harmful mouth bacteria.  Harmful mouth bacteria break down tooth structure causing cavities which is a bad thing.  Intestinal bacteria break down food particles causing it to adsorb through the intestinal wall which is a good thing.  So does ingested xylitol interfere with nutrition?

To minimize the impact of xylitol on the intestines, it would seem to follow that a smaller amount  used as a mouth wash periodically throughout the day would have the same positive effect on the teeth while minimizing the negative effect on the bowels.  On the other hand, if ingested xylitol makes its way to the saliva, and the changes to intestinal flora has no deleterious impact on nutrition, then a large dose followed by smaller additions makes more sense.

I would appreciate any information you have that would clarify this situation.

Thank you,


Dear Mr. B,

Thank you for your interesting question. I understand your approach from a logical perspective, but I think the
deductions that apply to fluoride, should not be applied to xylitol.

My experience is that it is important to trust your manufacturer particularly when buying granular xylitol (All xylitol is not created equal try another brand). Not to toot my own horn, but I have often heard how superior Zellies granular xylitol tastes!

First and foremost, xylitol is found in the human body about 15 g is produce daily. Second, xylitol is part of some programs to help restore health in terminally sick patients. Assuming you have high quality xylitol the effect on the G.I. will be influenced by the fact that xylitol behaves as fiber.

In the 70s, some oral care companies were afraid of the advent of xylitol. I believe it was these companies who created confusion between artificial sweeteners, sorbitol, and xylitol. (The tactic was effective and put xylitol on the back burner for 30 years! )

Even today, most health professionals incorrectly view xylitol as an artificial sweetener that causes G.I. problems. I argue it is a health sugar, has many general health benefits , provides fiber, has a low glycemic index, and stabilizes blood sugars. (Not to mention its oral health benefits!!!)

There are studies showing xylitol tolerance at quite high dosages. Children and infants are able to tolerate 10 to 20 g with ease. I suggest it balances G.I. health.

Xylitol is not a probiotic, but I suggest it is a prebiotic preparing the mouth and the G.I. tract for healthy bacteria. I suggest the use of a probiotic with regular small amounts of xylitol. In those who have made this a routine, particularly the elderly, they have prevented problems with E. coli infections and other gastric disturbances. Acid reflux appears to be improved with xylitol, and this seems connected.

From an oral health standpoint, you certainly can rinse with xylitol 3 to 5 times a day after meals and achieve oral health benefits. Personally, I suggest 1 g amounts, five or more times a day.

I hope this helps alleviate your concern. I believe intestinal health is critical for our immune system and xylitol is on your side!! I believe the problems for our GI are: ingestion of mercury from poor quality or failing mercury fillings, products (like anti-acids or coffee creamers) that contain aluminum, certain preservatives, and of course antibiotics all of which create unhealthy G.I. environments.

Please keep in touch and I hope I have answered your questions.
Best wishes

26 Corporate Woods
Rochester, NY 14623

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