What Are Sugar Alcohols?
Erythritol and xylitol are both members of a family of carbohydrates known as polyols, or sugar alcohols. Despite the name, they contain no ethanol and are not alcoholic. They are naturally occurring in various fruits and vegetables but are commercially produced for use as low-calorie sweeteners.
Unlike table sugar, sugar alcohols are not completely absorbed by the body, which is why they contribute fewer calories and have a lesser impact on blood sugar. This makes them popular choices for individuals on low-carb diets, managing diabetes, or aiming for weight loss. However, the similarities largely end there, as their chemical structures, metabolism, and effects on the body differ significantly.
Erythritol: The Low-Calorie Choice
Erythritol is a sugar alcohol that is typically produced by fermenting glucose, often from cornstarch. It is known for its near-zero caloric content, providing only about 0.2 calories per gram because it is poorly absorbed by the digestive system. The majority of ingested erythritol (about 90%) passes into the bloodstream and is eventually excreted unchanged in the urine within 24 hours.
This unique absorption process is why erythritol is generally well-tolerated and less likely to cause the digestive distress commonly associated with other sugar alcohols, such as bloating and gas. While it is about 70% as sweet as sugar, it has a clean taste with a noticeable cooling sensation in the mouth. This cooling effect makes it a good fit for certain products like mints, but less desirable for others. Erythritol has a glycemic index of 0, meaning it has no effect on blood sugar or insulin levels.
Xylitol: The Sweetness Match for Sugar
Xylitol is a sugar alcohol that is commercially derived from corncobs or birch trees. It is roughly as sweet as table sugar, making it a convenient 1:1 replacement in many recipes. Xylitol contains 2.4 calories per gram, which is significantly higher than erythritol but still less than sugar.
In the body, a portion of xylitol is metabolized in the liver, while the remainder travels to the large intestine where it can cause fermentation. This can lead to digestive side effects like gas, bloating, and diarrhea, especially when consumed in larger quantities. Unlike erythritol, xylitol has a low but not zero glycemic index, with a GI value around 7-13.
One of the most important distinctions is xylitol's extreme toxicity to dogs. Even small amounts can cause a rapid and dangerous drop in blood sugar, so it is vital for pet owners to keep xylitol-containing products out of reach.
Erythritol vs. Xylitol Comparison Table
| Feature | Erythritol | Xylitol |
|---|---|---|
| Sourcing | Typically produced via glucose fermentation from cornstarch. | Extracted from corncobs, birch trees, or other plants. |
| Caloric Content | Nearly zero calories (~0.2 kcal/g). | Higher caloric content (~2.4 kcal/g). |
| Sweetness | ~70% as sweet as sugar. | Same sweetness as sugar (1:1 ratio). |
| Taste Profile | Clean taste with a distinct cooling sensation. | Very similar taste to sugar; no significant aftertaste. |
| Glycemic Impact | Glycemic index of 0; no effect on blood sugar. | Low glycemic index (7-13); minimal effect on blood sugar. |
| Digestive Tolerance | Highly tolerated with minimal digestive issues due to high absorption. | Can cause bloating, gas, and diarrhea in larger quantities due to gut fermentation. |
| Baking Performance | May not provide the same texture and moisture as sugar. | Performs well in baking, retaining moisture and texture. |
| Pet Safety | Not toxic to dogs. | Highly toxic to dogs; must be kept away from pets. |
Health Implications and Usage
Impact on Blood Sugar
Both erythritol and xylitol are far superior to table sugar for individuals with diabetes or insulin resistance. Erythritol, with its zero glycemic index, is the better option for those needing strict blood sugar control, as it causes no spike in blood glucose or insulin. Xylitol's low GI means it has a minimal impact, but it's not entirely zero.
Digestive Concerns
For people sensitive to sugar alcohols, erythritol is often the preferred choice due to its better digestive tolerance. A large portion of erythritol is absorbed before it can cause problems in the large intestine. In contrast, xylitol is more likely to cause gastrointestinal discomfort in sensitive individuals, especially if consumed in large amounts.
Dental Health Benefits
Both erythritol and xylitol are non-cariogenic, meaning they do not feed the oral bacteria that cause tooth decay. This is why they are often used in sugar-free gums, toothpastes, and mints. Some studies suggest that erythritol may be even more effective at inhibiting the growth of oral bacteria than xylitol, while xylitol is also known for reducing plaque and promoting remineralization.
Emerging Cardiovascular Risks
Recent observational studies have raised potential concerns about a link between high levels of erythritol and xylitol in the blood and an increased risk of cardiovascular events, such as heart attack and stroke. However, these studies have limitations, and more research is needed to fully understand any potential connection and the long-term safety of these sweeteners, especially in large doses. It is prudent to use all sugar alternatives in moderation as part of a balanced diet.
Making the Right Choice for Your Diet
The choice between erythritol and xylitol often depends on your specific health goals and personal preferences. For strict calorie and carbohydrate reduction, erythritol is the clear winner with its near-zero caloric content and glycemic index. For those prioritizing dental health and looking for a sweetener with a taste and sweetness level very similar to sugar, xylitol is an excellent option. However, those with pets must remember the serious risks associated with xylitol. Ultimately, both are considered better for blood sugar management and dental health than table sugar, and moderation is key regardless of which you choose.
Using Erythritol and Xylitol in Your Kitchen
- Erythritol: Best for low-calorie recipes and sweetening beverages where the cooling effect is acceptable. Often used in keto-friendly chocolates and some reduced-sugar foods. When baking, you may need to use more to achieve the desired sweetness.
- Xylitol: A great 1:1 sugar replacement in many baking recipes, as it retains moisture and texture better than erythritol. Excellent for making sauces and caramels.
To ensure optimal usage, always read recipes and adjust quantities accordingly, especially when substituting sweeteners, as their relative sweetness and bulk differ. For households with pets, double-checking labels for xylitol is essential to ensure safety.
Conclusion
While erythritol and xylitol are both effective sugar alcohols, they are not the same. They offer different benefits and drawbacks regarding calories, sweetness, digestion, and safety. Erythritol provides near-zero calories and a negligible glycemic impact, making it ideal for strict diets, but it is less sweet and has a cooling aftertaste. Xylitol matches sugar's sweetness and works well in baking but has more calories and is more likely to cause digestive issues in larger amounts. The crucial difference is xylitol's toxicity to dogs. By understanding these distinctions, consumers can make informed choices based on their nutritional needs and health priorities.
Center for Science in the Public Interest: Chemical Cuisine classifies erythritol as safe while advising limitations on xylitol.
