Is Xylitol Safe?

Is Xylitol SafeFor a very long time, I resisted using any type of sugar substitute. Even when I knew that I no longer wanted to use sugar (it’s highly-processed; raises blood sugar; it has no nutritional benefits so it’s empty calories; and it’s bad for teeth and gums), I opted to simply reduce the amount of white sugar I used in recipes, or to use more natural and nutritious substitutes such as honey and maple syrup.

I knew to stay away from artificial, laboratory-made sweeteners. Aspartame (brand names NutraSweet and Equal) contains phenylalanine, high levels of which can result in brain damage. Saccharine (brand name Sweet ‘n Low) has been shown, in animal studies, to cause cancer. And Sucralose (brand name Splenda) is too new to know for sure if it’s safe – it was only approved by the FDA in 1998.

But I was on the fence about stevia, xylitol and erythritol, sweeteners that are derived from natural sources (stevia leaf, birch tree, corn), although admittedly highly processed and never found in nature in the highly concentrated form we use for baking (much like processed sugar vs. a sugar cane).

I gave Stevia a try after Mark Sisson had convinced me, in a well-researched article, that Stevia is safe and perhaps even beneficial. But I couldn’t get past the unpleasant aftertaste. It was just not worth it.

Then I decided to look into xylitol. I saw it at Whole Foods Market, right next to stevia, and I know that Whole Foods as a general rule does not sell crap, so that was a good sign. I started researching the subject (Xylitol research has been conducted for the past 50 years, since the early 1970’s, so it’s not a new player and has been extensively researched), and this is what I came up with:

Xylitol is a sugar alcohol. Sugar alcohols are low-digestible carbohydrates, like fiber and resistant starch. They occur naturally in many fruits and are only partially absorbed by the body (50% of xylitol is absorbed), so they do provide some calories. The chemical structure of a sugar alcohol is a hybrid between a sugar molecule and an alcohol molecule, which is why they are called sugar alcohols.

Sugar alcohols have a low glycemic index. They do not cause changes in blood glucose or insulin in humans, and animal studies indicate that xylitol reduces body weight, blood glucose, and serum lipids, and increases glucose tolerance. Some studies show that sugar alcohols also have a prebiotic effect, positively influencing gut flora.

An advantage specific to xylitol is its ability to improve dental health and prevent tooth decay. In addition, some studies indicate it might be helpful in preventing age-related decline in bone and skin health and in treating or preventing osteoporosis.

The main disadvantage of sugar alcohols is that they can cause digestive distress. Similarly to other forms of indigestible carbohydrate (fiber and resistant starch), they can initially cause diarrhea, gas and bloating, so it’s best to start slowly and experiment to find your own tolerance level. If you suffer from Irritable Bowl Syndrome, sugar alcohols are probably not for you. Another drawback of xylitol is that it’s very toxic to some pets.

Xylitol has about half the calories of sugar, and about the same level of sweetness. It has minimal effect on blood glucose and does not affect insulin levels. It looks like sugar, tastes like sugar and acts like sugar in cooking and baking. It has no aftertaste, just a pleasant sweetness. While I still believe that honey is a much more natural choice, it does significantly raise my blood sugar levels, so I’ve been switching to sugar alcohols.

How do I calculate carbs from sugar alcohols? 50% of xylitol is absorbed, and a teaspoon contains 4 grams of carbs, so theoretically when calculating carbs in recipes that contain xylitol, each teaspoon should provide 2 grams net carbs. However, research shows that in most people xylitol does not raise blood sugar or insulin levels, so in my recipes I calculate xylitol az zero grams carbs.

As for erythritol, it has 70% the sweetness of sugar, less than 1 calorie per teaspoon, no effect on blood sugar or insulin levels, and no unpleasant digestive side effects when consumed in reasonable amounts. I’ve been using it more and more recently in baked goods and desserts, because one of us can’t really handle xylitol, but has no issues with erythritol. I generally use is as I would use sugar or xylitol, adding 25% more to the recipe, so 1 cup of sugar would be 1 1/4 cups of erythritol.

Is xylitol safe? It’s not as safe or as natural as honey, but for those of us who can’t handle honey in terms of blood sugar, I believe xylitol and erythritol are good, safe alternatives, and that’s why I use them in my recipes.

Mark’s Daily Apple
Chris Kresser
Dr. Mercola
US National Library of Medicine