What are Erythritol and Sorbitol? An Overview
Erythritol and sorbitol are both sugar alcohols, also known as polyols, that are commonly used as low-calorie sweeteners and bulking agents in a wide variety of food products. Both provide a sweet taste without the high caloric load or blood sugar spike associated with regular table sugar. However, despite their similar classification, they have distinct chemical structures, metabolic pathways, and functional properties that affect their use in foods and their impact on the human body. Erythritol is a four-carbon polyol, while sorbitol has a six-carbon structure. This structural difference is the foundation for their divergent characteristics.
How Erythritol and Sorbitol Differ in Metabolism
One of the most critical distinctions between these two sugar alcohols is how the body processes them. Erythritol is unique among polyols because it is almost entirely absorbed into the bloodstream in the small intestine before it can reach the large intestine and be fermented by gut bacteria. Once absorbed, it is excreted unchanged in the urine within 24 hours, meaning it provides virtually zero calories. This metabolic path explains why it has a near-zero glycemic index and minimal digestive impact.
Conversely, a much smaller percentage of sorbitol is absorbed by the small intestine. The unabsorbed portion travels to the large intestine, where it is fermented by gut bacteria. This fermentation process is what can lead to common sugar alcohol side effects like gas, bloating, and diarrhea, especially when consumed in large quantities. Sorbitol's partial absorption and fermentation mean it still contributes a small number of calories and has a low, but not zero, glycemic index.
Comparison Table: Erythritol vs. Sorbitol
| Feature | Erythritol | Sorbitol |
|---|---|---|
| Caloric Content | Nearly zero (approx. 0.2 kcal/g) | About 60% of sugar (approx. 2.6 kcal/g) |
| Relative Sweetness | 60–80% as sweet as table sugar | Approximately 60% as sweet as table sugar |
| Glycemic Index (GI) | Zero, does not impact blood sugar | Low, but not zero (GI of 4) |
| Digestive Tolerance | Very high; less likely to cause digestive issues | Lower; larger amounts can cause bloating, gas, and laxative effects |
| Mouthfeel | Endothermic cooling effect (minty taste) | Cool, sweet taste without a strong cooling sensation |
| Culinary Uses | Baking, beverages, tabletop sweeteners | Sugar-free gums, candies, baked goods (humectant) |
| Best For | Keto diets, calorie-conscious, sensitive digestion | Maintaining moisture in food products, general sugar-free items |
Flavor Profile and Culinary Functionality
The sensory experience of erythritol and sorbitol also sets them apart. Erythritol is known for its distinct cooling sensation in the mouth, which is a result of it absorbing heat as it dissolves. While this can be refreshing in some applications, it may be undesirable in others. It has a clean, sugar-like taste but is less sweet than sugar, often requiring a blend with other high-intensity sweeteners to achieve a similar sweetness level. Erythritol is also not as soluble in liquids as table sugar.
Sorbitol, being about 60% as sweet as sugar, offers a more classic sweetness without the pronounced cooling effect. Its primary advantage in food manufacturing is its excellent humectant (moisture-retaining) property. This makes it a popular choice for maintaining the texture and freshness of products like candies, baked goods, and sugar-free chewing gums. However, when used as a bulk sugar replacer in baking, a study found it resulted in a softer muffin texture compared to sucrose.
Health Considerations: Blood Sugar and Dental Health
For individuals with diabetes or those following a low-carb diet like keto, erythritol is generally the superior choice. With a glycemic index of zero, it does not raise blood sugar or insulin levels. Sorbitol, while having a low GI, can still cause a small rise in blood sugar, making erythritol a safer bet for tight blood sugar control.
In terms of dental health, both sugar alcohols are considered non-cariogenic, meaning they don't contribute to tooth decay. Oral bacteria cannot ferment them into the acids that erode tooth enamel. Interestingly, research has suggested that erythritol may even offer better oral health benefits than sorbitol, potentially reducing dental plaque more effectively.
Conclusion
Ultimately, the choice between erythritol and sorbitol depends on your priorities and intended use. For those seeking minimal digestive side effects, virtually zero calories, and no impact on blood sugar, erythritol is the clear winner. Its use is ideal for keto and low-carb diets. Sorbitol, while still a low-calorie alternative to sugar, is best utilized for its specific functional properties in food products, such as moisture retention. However, its potential for gastrointestinal distress at higher doses must be taken into consideration. By understanding the key differences in their digestion, caloric impact, and culinary performance, consumers can make an informed choice that best suits their health goals.
