Sugar alcohols are a type of carbohydrate used as sweeteners in sugar-free and reduced-sugar foods. Despite the name, they contain no ethanol and won’t make you intoxicated. Their chemical structure simply resembles both sugar and alcohol at the molecular level, which is where the confusing name comes from. You’ll find them in sugar-free gum, protein bars, candy, ice cream, and many “keto-friendly” or “diabetic-friendly” products.
How Sugar Alcohols Differ From Sugar
Regular table sugar delivers about 4 calories per gram and is fully absorbed in your small intestine. Sugar alcohols provide fewer calories, typically ranging from about 0.2 to 3 calories per gram depending on the type. They also raise blood sugar more slowly and to a lesser degree than regular sugar, which is why they’re popular in products marketed to people managing diabetes or watching carbohydrate intake.
The sweetness varies by type. Xylitol tastes about as sweet as sugar. Erythritol is roughly 60 to 70 percent as sweet. Sorbitol lands around 60 percent. Maltitol comes closest to sugar’s sweetness at about 75 to 90 percent, which is why it shows up in so many sugar-free chocolates and baked goods. None of them deliver quite the same flavor profile as sugar, and some leave a mild cooling sensation on the tongue.
Common Types and Where They Come From
Sugar alcohols occur naturally in many fruits and vegetables, though commercial versions are manufactured from starches and sugars. The most common ones you’ll encounter on ingredient labels include:
- Sorbitol: Found naturally in many fruits and vegetables. Widely used in sugar-free candies, cough syrups, and toothpaste.
- Xylitol: Sometimes called “wood sugar” because it occurs naturally in straw, corncobs, and certain cereals, as well as fruits and mushrooms. Most commonly associated with sugar-free gum.
- Erythritol: Naturally present in some fermented foods. Has the fewest calories of any sugar alcohol (about 0.2 per gram) and causes the least digestive trouble at moderate doses.
- Maltitol: Commonly used in sugar-free chocolate and baked goods because its sweetness and texture closely mimic sugar.
- Mannitol: Occurs naturally in pineapples, olives, asparagus, sweet potatoes, and carrots.
Why They Cause Digestive Problems
The most well-known downside of sugar alcohols is their effect on your gut. Because your small intestine can only partially absorb most sugar alcohols, the unabsorbed portion travels to your large intestine, where bacteria ferment it and produce gas. At the same time, the unabsorbed sugar alcohol draws water into the intestine through osmosis, softening stool and increasing intestinal pressure. This is the same mechanism used in osmotic laxatives.
The result: bloating, gas, cramping, and diarrhea, especially when you eat too much at once. Sorbitol and maltitol are the worst offenders. As little as 10 grams of sorbitol can trigger symptoms in sensitive individuals, and many sugar-free products contain more than that per serving. Erythritol is better tolerated because roughly 90 percent of it gets absorbed in the small intestine before reaching the colon, but large doses can still cause nausea.
If you’ve ever eaten a whole bag of sugar-free gummy bears and spent the next few hours in serious distress, this is why. Your tolerance tends to improve gradually with regular small exposures, but the threshold varies widely from person to person.
How to Read Sugar Alcohols on Labels
Sugar alcohols appear on nutrition labels under “Total Carbohydrate,” listed separately from regular sugars. If you’re counting carbohydrates for blood sugar management, the UCSF Diabetes Teaching Center recommends subtracting half the grams of sugar alcohol from total carbohydrates to estimate your effective carb count. So a product with 29 grams of total carbohydrate and 18 grams of sugar alcohol would count as about 20 grams of carbohydrate (29 minus 9).
This half-credit approach reflects the fact that sugar alcohols are partially absorbed and do raise blood sugar to some degree. Erythritol is an exception since it has almost no impact on blood sugar, but the half-subtraction rule serves as a reasonable general guideline across all types.
Dental Benefits of Xylitol
Unlike sugar, most sugar alcohols don’t feed the bacteria that cause tooth decay. Xylitol goes a step further and actively fights cavities. The primary cavity-causing bacterium, Streptococcus mutans, absorbs xylitol the way it would absorb regular sugar, but it can’t extract energy from it. The bacterium spends energy pulling xylitol in, processing it, and expelling it, gaining nothing in return. Over time, this essentially starves the bacteria and reduces their population in your mouth.
Research suggests a daily dose of 6 to 10 grams of xylitol, spread across multiple exposures (like chewing gum several times a day), provides meaningful cavity prevention. This is why xylitol gum is recommended by many dental professionals.
Erythritol and Heart Health Concerns
Erythritol has been the subject of growing concern after research published in the American Heart Association’s journal linked it to increased clotting risk. In a study of healthy volunteers, consuming 30 grams of erythritol (a typical amount found in a keto-sweetened beverage or baked good) caused plasma erythritol levels to spike more than 1,000-fold. This spike enhanced platelet reactivity across every measure tested, meaning blood cells became significantly more prone to clumping together. The same dose of glucose produced no such effect.
Separate observational studies found that elevated fasting levels of erythritol in the blood were associated with higher three-year risk of heart attack, stroke, or death, independent of traditional risk factors like cholesterol or blood pressure. These findings held up in both U.S. and European cohorts. Researchers have called for a reevaluation of erythritol’s “Generally Recognized as Safe” status.
This doesn’t mean erythritol definitively causes heart attacks. The observational studies can’t prove causation, and the interventional study was small (10 people per group). But if you have existing cardiovascular risk factors or consume erythritol-sweetened products daily, it’s worth paying attention as more research develops.
Xylitol Is Toxic to Dogs
One critical safety issue: xylitol is extremely dangerous for dogs. Dogs that ingest more than 0.1 grams per kilogram of body weight risk severe hypoglycemia, because xylitol triggers a massive insulin release in dogs that it doesn’t cause in humans. At doses above 0.5 grams per kilogram, acute liver failure can occur. For a 20-pound dog, just a couple of pieces of xylitol-sweetened gum could be life-threatening.
Xylitol appears in gum, candy, peanut butter, baked goods, toothpaste, and some medications. If your dog gets into any product containing xylitol, it’s a veterinary emergency. Some products now list xylitol under the alternate name “birch sugar,” so check ingredient lists carefully if you have pets in the house.