By Sherri Shafer

Sugar alcohol is a modified form of carbohydrate. Many products that claim to be sugar free are sweetened with a substance known as sugar alcohol (or polyol). Despite the name, sugar alcohol does not have any sugar, and it does not have any alcohol. Hydrogen is added to various forms of carbohydrate and chemical bonds are shifted, and then voilá — you have a new form of carbohydrate known as sugar alcohol.

Many candies, cookies, ice creams, puddings, and syrups claim to be “sugar free.” That doesn’t mean they are carbohydrate free or calorie free. The label claim on the front of the package doesn’t necessarily tell the whole story.

Because technically the sugar has been altered, the product can be labeled as being “sugar free.” The resulting sweetener is renamed “sugar alcohol.” When you view the Nutrition Facts on food labels, the total carbohydrate count doesn’t change much, if at all. It may say “0” grams of sugar, but look below that to find the grams of sugar alcohol. Either way, the total carbohydrate is what you need to focus on.

Many so called “sugar-free” sweets are still high in carbs, fats, and calories. In fact, the counts are often comparable to their regular sugar–containing counterparts. Beware: Some people experience gas, cramping, or loose stools because sugar alcohol can be difficult to digest and absorb. The portion that remains undigested is fermented by bacteria in the large intestine. Unfortunately, that can result in problems such as gas, cramping, bloating, and perhaps diarrhea. Sugar-free gum has only a small amount of sugar alcohol, so digestive complaints are rare. If you eat too much sugar-free candy or ice cream, you may end up regretting it. Tolerance is variable and dose dependent. Some people have no adverse symptoms at all.

Not all types of sugar alcohol are the same. Some are better tolerated than others. Products sweetened with mannitol or sorbitol are required to carry a label warning stating that some users may experience a laxative effect. The other sugar alcohols don’t need to carry such a warning.

Sugar alcohol can be created from single units of sugar, double units of sugar, or chains of sugars:

  • Single sugars (monosaccharides) such as glucose and fructose are modified to make sorbitol and mannitol respectively.
  • Double sugars (disaccharides) are also used to produce sugar alcohol. For example, the lactose from milk can be turned into lactitol.
  • Starch fragments (polysaccharides) are modified to create hydrogenated starch hydrolysates.

The table shows examples of sugar alcohols.

Examples of Sugar Alcohol

Made from Monosaccharides Made from Disaccharides Made from Polysaccharides
Sorbitol Maltitol Maltitol syrup
Mannitol Isomalt Hydrogenated starch hydrolysates (HSH)
Erythritol Lactitol
Xylitol

While entirely safe for humans, xylitol is toxic to our canine and feline friends, so make sure your dogs and cats don’t eat any products sweetened with xylitol. This particular sweetener stimulates the release of insulin in pets, which can lead to hypoglycemia, seizures, liver problems, or death. This doesn’t happen to humans, so you’re not at risk. Pet owners must be made aware, though.

Why do food scientists go through all of this trouble to create sugar alcohol out of sugars and starches? Well, there are a few benefits. For one thing, sugar alcohol doesn’t promote cavities. Secondly, there may be a reduced effect on blood-glucose levels when using sugar alcohol rather than other caloric sweeteners. Because sugar alcohol is not well digested, fewer calories are absorbed (but with that comes the risk of gas and diarrhea). Sugar alcohol adds texture, bulk, a desirable “mouthfeel,” and retention of moisture to the products that incorporate it. Nonnutritive sweeteners do not offer those properties.

If you count carbs and base your insulin dose on the grams of carbohydrate you eat, then you may consider a modified approach when eating a product made with sugar alcohol. Because sugar alcohol is not fully digestible, take insulin for only half the amount of sugar alcohol in the product. You can also deduct the grams of fiber from the total carbohydrate because fiber doesn’t digest. Discuss the concept with your healthcare providers before changing the way you calculate your insulin dose. See the figure for tips on deciphering digestible carbohydrate when reading Nutrition Facts food labels on items that contain sugar alcohol.

diabetes-carb-sugar-alcohol
Calculating digestible carb when you eat a product with sugar alcohol.

One thing to consider, especially if sugar alcohol gives you abdominal discomfort, is that you can choose to buy the regular version of the product, which in the example happens to be cookies. If it turns out that the regular sugar–containing version has 20 grams of carb, then you would simply take the dose needed to cover the 20 grams of carb.