What are sugar alcohols?
Despite their name, sugar alcohols (also known as polyols) are neither sugar nor do they contain ethanol, the alcohol found in alcoholic beverages. Instead, they are a class of carbohydrates that possess a chemical structure resembling both. They are used as low-calorie sweeteners and bulking agents in many processed foods, particularly those labeled 'sugar-free' or 'no sugar added,' such as chewing gum, hard candies, and baked goods.
Unlike table sugar, which provides about 4 calories per gram, sugar alcohols contain fewer calories because they are not completely absorbed by the small intestine. This incomplete digestion means they have a less significant impact on blood sugar, which is why they are often popular among people with diabetes or those following low-carb and ketogenic diets.
Common sugar alcohols you might find on an ingredients list include erythritol, xylitol, maltitol, sorbitol, and lactitol.
The crucial difference between total and net carbs
For many dieting plans, especially low-carb and keto, the concept of 'net carbs' is fundamental. Net carbs are the carbohydrates that are actually digested and absorbed by the body, thus impacting blood sugar. The simple equation for calculating net carbs is to subtract fiber and sugar alcohols from total carbohydrates. However, this is where the nuance comes in, and a blanket subtraction is not appropriate for all sugar alcohols.
While the term 'net carbs' is widely used by consumers and food manufacturers, it is not officially defined or recognized by regulatory bodies like the FDA or the American Diabetes Association. This is because not all sugar alcohols are created equal, and their digestion and caloric contribution can vary significantly. Relying solely on the 'net carb' claim on a package can be misleading, and doing your own calculation based on the specific type of polyol is the more accurate approach.
A guide to counting specific sugar alcohols
To correctly incorporate sugar alcohols into your diet, you need to know how each type affects your body. The general rule for most is to count half of their grams toward your total carb count, but erythritol is a notable exception.
Here is a breakdown of how to count common polyols:
- Erythritol: This polyol is unique because it is largely absorbed into the bloodstream before being excreted unchanged in the urine, meaning it has virtually no effect on blood sugar and provides nearly zero calories. For this reason, the full amount of erythritol can be subtracted when calculating net carbs.
- Maltitol, Sorbitol, and Isomalt: These sugar alcohols are less easily digested and have a more moderate impact on blood glucose. The standard recommendation is to subtract only half of their grams from the total carbohydrate count.
- Xylitol: With a sweetness similar to sugar, xylitol is well-absorbed but still contains fewer calories. It is generally advised to count half of its grams as well, but some people can tolerate larger amounts with fewer digestive issues.
The right way to calculate net carbs
To practice, let's look at an example using a food label from a hypothetical protein bar with 25g Total Carbohydrates, 5g Dietary Fiber, and 10g Sugar Alcohol (Maltitol). The formula is:
- Start with Total Carbohydrates: 25g
- Subtract Dietary Fiber: 25g - 5g = 20g
- Subtract half of the Sugar Alcohols (Maltitol): 20g - (10g / 2) = 15g
This means you would count 15g of net carbs for this serving. This method is more precise than a simple subtraction and is especially important for those managing blood sugar, such as individuals with diabetes.
Potential drawbacks of sugar alcohol consumption
While sugar alcohols offer clear benefits over traditional sugar, they are not without potential downsides. The incomplete absorption process that makes them low-calorie is also the cause of their most common negative side effects.
- Gastrointestinal Issues: Excessive consumption of polyols can lead to bloating, gas, stomach cramping, and diarrhea. This happens because the unabsorbed sugar alcohols ferment in the large intestine. Sensitivity varies, and some people may experience symptoms with relatively small amounts.
- Laxative Effect: Some polyols, notably sorbitol and mannitol, can have a strong laxative effect, especially in high doses, due to their ability to draw water into the large intestine.
- Emerging Health Concerns: Recent observational studies have raised potential concerns, associating high circulating levels of erythritol and xylitol with an increased risk of major cardiovascular events like heart attack and stroke in at-risk individuals. While more research is needed to confirm a causal link, experts recommend caution and moderation.
Sugar alcohol comparison table
| Sugar Alcohol | Relative Sweetness (vs. Sugar) | Calories (per gram) | Common Uses | Digestibility & GI Impact | Notes |
|---|---|---|---|---|---|
| Erythritol | ~60-80% | ~0.24 | Keto baked goods, beverages, tabletop sweeteners | Minimal | Very low impact on blood sugar; easily tolerated. |
| Xylitol | ~100% | ~2.4 | Gum, mints, oral care products, candies | Partially | Similar sweetness to sugar; highly toxic to dogs. |
| Maltitol | ~75% | ~2.1 | Sugar-free chocolate, hard candies, baked goods | Partially | Creamy texture; higher caloric and GI impact than some polyols. |
| Sorbitol | ~50% | ~2.6 | Sugar-free foods, jams, soft candies | Partially | Cooling effect; known for laxative properties in higher doses. |
| Isomalt | ~45-65% | ~2.0 | Hard candies, toffee | Partially | Good for baking as it doesn't brown or caramelize easily. |
| Lactitol | ~30-40% | ~2.0 | Sugar-free ice cream, chocolate, baked goods | Partially | Mild sweetness; lower GI impact. |
A measured approach to sugar alcohols
Incorporating sugar alcohols into your diet requires a thoughtful, measured approach rather than a simple rule of avoidance or unlimited consumption. Moderation is essential, as the threshold for potential GI side effects varies significantly between individuals and across different polyols. It is important to treat foods labeled 'sugar-free' not as 'free foods,' but as items that require careful carbohydrate counting and consideration.
For those managing specific health conditions, such as diabetes or a low-FODMAP diet, individual responses to sugar alcohols must be monitored. The American Diabetes Association recommends using total carbs and closely monitoring blood glucose when consuming foods with sugar alcohols to determine their effect on your body. Pairing foods containing sugar alcohols with fiber, protein, and fats can also help slow digestion and stabilize blood glucose levels.
Conclusion: Navigating sugar alcohols in your diet
In summary, the answer to should you count sugar alcohol? is a definitive yes, but the method matters greatly. A simple approach is to use the 'net carb' calculation of subtracting all fiber and half the grams of most sugar alcohols, with the notable exception of erythritol, which can be fully subtracted due to its minimal impact. Be mindful of potential gastrointestinal issues and emerging research on other health effects, especially with higher consumption levels. Ultimately, a balanced, whole-foods-focused diet remains the foundation of good nutrition, with sugar alcohols best reserved for occasional treats in moderation. For more information on navigating sweeteners, consider resources like the American Diabetes Association's guidance on the topic.
