What Are Sugar Alcohols?
Sugar alcohols, also known as polyols, are a type of carbohydrate used as low-calorie sweeteners and bulking agents in many foods labeled "sugar-free" or "no added sugar". Despite their name, they contain no ethanol and will not cause intoxication. They are found naturally in small amounts in some fruits and vegetables but are most often manufactured for commercial use.
Unlike table sugar, sugar alcohols are only partially absorbed by the small intestine. The unabsorbed portion travels to the large intestine, where it is fermented by gut bacteria. This process is what gives them fewer calories than sugar and a lower impact on blood glucose levels, making them popular for people with diabetes or those following low-carb diets. However, this same slow absorption is responsible for their most common side effects: gas, bloating, and diarrhea, especially when consumed in large amounts.
Erythritol: The Popular Choice with Recent Concerns
For a long time, erythritol was considered one of the most promising sugar alcohols. Its benefits made it a favorite among manufacturers and consumers alike.
Benefits of Erythritol
- Superior Digestive Tolerance: About 90% of ingested erythritol is absorbed in the small intestine before reaching the large intestine, leading to significantly fewer gastrointestinal side effects compared to other polyols.
- Zero Glycemic Impact: Since the body does not metabolize it for energy, erythritol has a glycemic index of zero, meaning it does not raise blood sugar or insulin levels.
- Dental Health: Like xylitol, erythritol does not feed the oral bacteria responsible for plaque and cavities and may even help protect against tooth decay.
- Clean Taste: It has a pleasant, sugar-like taste with no significant aftertaste, though some may notice a cooling sensation.
Emerging Cardiovascular Risks
Despite its strong safety profile, recent research has raised concerns. In 2023, observational studies found a link between higher circulating levels of erythritol and an increased risk of major cardiovascular events, such as heart attack and stroke, in at-risk individuals. A subsequent human intervention study showed that ingesting a typical amount (30g) of erythritol led to a thousand-fold increase in blood levels, enhancing platelet reactivity and thrombosis potential for days. This is particularly concerning as foods with sugar alcohols are often targeted at people with diabetes, who already face a higher risk of heart issues. Further research is needed, but this information complicates the long-held view of erythritol as the safest sugar alcohol.
Xylitol: Great for Teeth, Harmful to Pets
Another common sugar alcohol, xylitol, is as sweet as sugar and well-regarded for its dental benefits. It is a frequent ingredient in sugar-free gum, toothpaste, and mints.
Considerations with Xylitol
- Digestive Side Effects: While generally well-tolerated in moderate amounts, high doses can cause gastrointestinal distress, including bloating, gas, and diarrhea, as it is fermented by gut bacteria.
- Extreme Toxicity to Dogs: This is a critical safety point. Xylitol is highly toxic to dogs, causing a rapid and dangerous release of insulin that can lead to hypoglycemia and liver failure. Pet owners must exercise extreme caution.
Other Common Sugar Alcohols
Sorbitol: Found naturally in fruits, sorbitol is about 60% as sweet as sugar and has a higher laxative effect than erythritol. Foods containing it are required by the FDA to carry a laxative warning if consumed excessively.
Maltitol: With a glycemic index of 35-60, maltitol impacts blood sugar more than other polyols. It has a very similar taste and texture to sugar but is also known to cause significant digestive distress in higher quantities.
Comparing Common Sugar Alcohols
| Feature | Erythritol | Xylitol | Sorbitol | Maltitol |
|---|---|---|---|---|
| Calories/gram | 0.24 | 2.4 | 2.6 | 2.1 |
| Relative Sweetness | ~70% of sugar | ~100% of sugar | ~60% of sugar | ~90% of sugar |
| Digestive Impact | Very low, highly tolerated | Moderate, higher doses cause issues | High, common laxative effect | High, common laxative effect |
| Glycemic Index | 0 | Very low | Low (4–9) | Moderate (35–60) |
| Cardiovascular Concerns | Emerging concerns from studies | Emerging concerns from studies | Not specified | Not specified |
Making the Safest Choice for Your Diet
Determining the absolute safest sugar alcohol is challenging and depends on individual health factors.
Prioritizing Digestive Health
If your primary concern is avoiding gastrointestinal discomfort, erythritol has historically been the best choice due to its high absorbability and low fermentability. However, the newer cardiovascular findings require serious consideration.
Prioritizing Cardiovascular Health
Given the recent studies, individuals with existing heart disease or risk factors like diabetes or hypertension may want to be cautious with erythritol and xylitol. For these individuals, exploring other natural, zero-calorie sweeteners like stevia or monk fruit extract could be a safer path. The World Health Organization (WHO) also recommends reducing the overall intake of all added sweeteners rather than relying heavily on substitutes.
A Balanced Perspective
The safest strategy often involves the principle of moderation. Introduce sugar alcohols slowly to assess your individual tolerance. The American Diabetes Association notes that sugar alcohols can be acceptable in moderation but should not be eaten in excess. For many people, a balanced approach means relying less on processed foods with any type of sweetener and focusing on whole, nutrient-dense foods. When you do use them, check labels for total carbohydrates, as foods containing sugar alcohols are not necessarily calorie-free.
Conclusion
Historically, erythritol was considered the safest sugar alcohol primarily due to its superior digestive tolerance. However, recent research linking erythritol to potential cardiovascular risks—particularly at the elevated blood levels seen after typical consumption—introduces a new level of caution. Other polyols like xylitol and sorbitol are more prone to causing digestive upset. Ultimately, the "safest" option is not a single product but a mindful approach to consumption. Moderation remains key, and exploring alternatives like stevia or monk fruit may be a prudent choice, especially for those at risk for heart disease. By paying close attention to both your body's tolerance and emerging scientific data, you can make an informed decision about the role of sugar alcohols in your nutrition plan.
For more detailed information on sugar alcohols and their health effects, visit Healthline's comprehensive guide.
