Sugar alcohols are not the same as sugar. They’re a distinct category of sweeteners that share some structural similarities with sugar but behave differently in your body, particularly when it comes to blood sugar, calories, and dental health. The name is misleading on both counts: sugar alcohols aren’t sugar, and they don’t contain the type of alcohol found in drinks.
How Sugar Alcohols Differ From Sugar
At the molecular level, sugar alcohols look a lot like sugar. The difference comes down to a single chemical tweak: one part of the sugar molecule is swapped out for a different chemical group. That small change preserves enough of sugar’s structure that sugar alcohols still taste sweet and behave similarly in food products, but it fundamentally changes how your body processes them.
Regular sugar (sucrose, fructose, glucose) is fully absorbed in your small intestine, quickly converted to energy, and raises your blood sugar rapidly. Sugar alcohols, by contrast, are poorly absorbed. Much of what you eat passes through without being fully digested, which is why they deliver fewer calories and have a much smaller effect on blood sugar. It’s also why they can cause bloating, gas, or diarrhea when consumed in larger amounts.
Common sugar alcohols you’ll see on ingredient labels include erythritol, xylitol, sorbitol, maltitol, and mannitol. Each one has a slightly different sweetness level and digestive profile, but they all follow this same general pattern of partial absorption.
Blood Sugar and Calorie Differences
This is where the practical gap between sugar and sugar alcohols matters most. Table sugar has a glycemic index around 65, meaning it causes a significant spike in blood sugar. Sugar alcohols range dramatically lower. Xylitol has a glycemic index of 12, and mannitol sits at just 2. Erythritol has essentially no effect on blood sugar at all.
Calorie content also differs. Regular sugar provides about 4 calories per gram. Most sugar alcohols contain roughly 1.5 to 3 calories per gram, with erythritol at the low end near zero. This combination of lower calories and minimal blood sugar impact is why sugar alcohols are so common in products marketed as “sugar-free” or “no sugar added,” including candy, protein bars, ice cream, and baked goods.
For people managing diabetes or watching their carbohydrate intake, sugar alcohols can be a useful tool. But “lower impact” doesn’t mean “no impact.” Maltitol, for instance, still raises blood sugar more than other sugar alcohols, so the specific type matters.
Effects on Dental Health
Sugar feeds the bacteria in your mouth that produce acid, and that acid eats away at tooth enamel. Sugar alcohols don’t. The bacteria responsible for cavities simply can’t break down sugar alcohols the way they break down regular sugar, so the acid levels in your mouth stay low enough that your enamel isn’t damaged.
Xylitol goes a step further. Regular xylitol use appears to shift the bacterial environment in your mouth over time. Cavity-causing bacteria in habitual xylitol users produce weaker, less sticky plaque that doesn’t adhere to teeth as effectively. This is why xylitol is a standard ingredient in sugar-free gum and why dental organizations have studied it as a cavity-prevention strategy, particularly in children.
How Sugar Alcohols Appear on Labels
On a Nutrition Facts panel, sugar alcohols are excluded from both the “Total Sugars” and “Added Sugars” lines. They fall under total carbohydrates instead, and their listing is actually voluntary under current FDA rules. Many manufacturers do include them, especially on products marketed as low-sugar or keto-friendly, but they aren’t required to unless they make a specific health claim.
This means a product can contain significant sugar alcohols and still say “0g sugar” on the label. If you’re trying to assess the full carbohydrate picture, check the ingredient list. Sugar alcohols typically end in “-ol” (sorbitol, maltitol, erythritol), making them relatively easy to spot.
Digestive Side Effects
Because sugar alcohols aren’t fully absorbed in the small intestine, they travel to the large intestine where gut bacteria ferment them. This fermentation produces gas and draws water into the intestine, which can lead to bloating, cramping, and diarrhea. The threshold varies from person to person, but consuming more than 10 to 20 grams in a sitting causes noticeable symptoms for many people.
Erythritol is the exception here. About 90% of it is absorbed in the small intestine and excreted in urine before it ever reaches the colon, so it causes far less digestive distress than sorbitol or maltitol. This is one reason erythritol has become the most popular sugar alcohol in recent years.
Emerging Cardiovascular Concerns
Erythritol’s popularity has also drawn more scrutiny. A study published in JACC: Advances followed older adults over roughly eight years and found that higher blood levels of erythritol were significantly associated with heart failure hospitalization, cardiovascular death, and overall mortality, even after adjusting for traditional risk factors like high blood pressure and cholesterol.
An important caveat makes these findings hard to interpret cleanly: your body produces erythritol on its own as a byproduct of metabolism, and current studies can’t easily distinguish between erythritol you ate and erythritol your body made internally. People with metabolic problems may naturally produce more erythritol, which could explain the association without erythritol itself being the cause. The long-term safety picture is still coming into focus, but it’s worth being aware of if you consume erythritol-sweetened products daily in large quantities.
Xylitol and Dog Safety
If you have dogs, this is critical information. Xylitol is extremely dangerous for dogs, even in small amounts. In most mammals, xylitol has no notable effect on insulin, but in dogs it triggers a rapid, massive insulin release that can cause life-threatening drops in blood sugar. Doses as low as 100 milligrams per kilogram of body weight can cause dangerous low blood sugar, and doses above 500 milligrams per kilogram can lead to liver failure.
To put that in perspective, a single piece of xylitol-sweetened gum can contain enough to poison a small dog. Keep all xylitol-containing products, including gum, mints, peanut butter, and baked goods, completely out of reach. Some product labels now use the name “birch sugar” instead of xylitol, so check ingredient lists carefully.