Sorbitol, Erythritol, Xylitol, and other Sugar Alcohols
Sugar alcohols are carbohydrates which are very similar to sugar, but slightly less caloric at about 2.4 calories per gram. They taste very similar to sucrose, though slightly less sweet, and some (such as sorbitol) are found naturally in certain fruits. Most of the sugar alcohol we consume will not be digested, so we don’t even absorb the 2.4 calories per gram advertised. Rather, the sugar alcohol is food for our gut flora, which while good, can cause gastric upset.
Xylitol and sorbitol are the two most popular sugar alcohols, but due to their laxative effect in high doses are usually only found in small items, such as chewing gum or mints. They are also found in oral care products because they will not cause tooth decay, so they may safely sweeten toothpaste and mouthwash.
Erythritol is the only common sugar alcohol actually to be absorbed by the small intestine, but it is passed intact through the urine. There is always the potential for accumulation when compounds are retained in our body, but studies have not reported any toxic effects in regards to its use. It is most commonly used in conjunction with stevia, and unlikely to cause problems at the levels present.
Due to the laxative effect most sugar alcohols have in moderate to large doses, they will probably not form a new generation of general-use low-calorie food sweeteners. While repeated use of sugar alcohols has been demonstrated to lessen the laxative effect, it is unlikely anybody would wish to go through the acclimation phase! In the small amounts found in mints and gum, they are effective as a sweetener and in prevention of tooth decay, and in the fruits they are found naturally in, they may contribute to the health of our gut.
The erythritol found in conjunction with some stevia-based sweeteners is unlikely to be of any issue, but is also unnecessary. For these reasons, sugar alcohols are safe sweeteners but of limited use. If you are willing to go through the gastric discomfort necessary to adapt to moderate intake, they may be a good way to sweeten food without adding calories. Elsewise, stick with stevia or don’t sweeten at all!
Are Real Sugars Healthier?
When we talk of sugars, the best place to start is with the monosaccharides. There are three total: glucose, fructose, and galactose. These are the simplest forms of sugar found naturally in food, and the only sugars which get absorbed through the intestine. All other carbohydrates, whether complex or simple, are made up of links of one or more of these three monosaccharides.
Glucose and Galactose
Glucose is the most important sugar our body uses. It is the primary fuel for our brain and is capable of running every organ in our body. In addition, our body can store glucose away in the muscles and liver in the form of glycogen, which is similar to the starch found in a potato. Glycogen is a long, branched chain of glucose molecules which is readily broken back down into glucose to supply a steady stream of energy for our brain and body. We store about 80-100 grams of glucose in our liver, in the form of glycogen.
Galactose is slightly less sweet than glucose, and the least common simple sugar. It is found primarily in dairy products, as a part of lactose (galactose + glucose), and is readily converted to glucose by the body.