Sugar alcohols have been used in diabetic foods for many years. With the rising level of obesity, sugar alcohols are now seen more frequently in nondiabetic foods, especially in products marketed for low-carb diets. After total carbohydrates, manufacturers are increasingly listing "net carbohydrates" or "impact carbohydrates" on product labels. These new categories were introduced following a ruling that forced the food industry to count sugar alcohols as carbohydrates. Suddenly, low-carb food products had carbohydrates - and that was bad for business. To calculate net or impact carbs, companies subtract the grams of sugar alcohols and (in many cases) fiber from the total carbohydrate count; what's left is essentially the amount of starch(es)/sugar(s) in the product. Net or impact carbohydrates are not recognized by any regulatory agency. I believe this is the first time industry has responded to a ruling it opposed by inventing a new macronutrient subclassification.
Sugar alcohols are actually a group of compounds, formerly known as polyhydric alcohols, now called polyols. These are nonsugar carbohydrates that are considered reduced-calorie bulk sweeteners, because they have a mass similar to sugar. Sugar alcohols are slowly absorbed (therefore, they have a minimal effect on blood glucose and insulin); poorly digested (large amounts have a laxative effect in some people, and may cause gas or bloating in others); and do not cause tooth decay (oral bacteria cannot break them down). They resist mold and bacteria better than sugar because they do not absorb as much water as does sugar. Sugar alcohols may be cooked, but (unlike sugar) do not brown with heat. Sugar alcohols got their name because one part of their molecular structure resembles an alcohol molecule, and the other part resembles a sugar molecule. They are neither sugar molecules nor alcohol molecules. Their misleading name continues to generate confusion.
|Name||Calories Per Gram||Sweetness1 Relative to Sugar||USA Regulatory Status||Source||Comments|
|Erythritol||0.02||70%||GRAS2||fermentation product of glucose||the sugar alcohol with the lowest amount of both gastrointestinal side-effects and calorie|
|Hydrogenated starch hydrolysates3||2.4-3.0||40-90%||GRAS||partial hydrolysis of corn, potato, or wheat starch||calories and sweetness vary depending on the starch source and the extent of hydrolysis; there are a number of HSH subgroups|
|Isomalt||2.0||55%||GRAS||oxygen is added to the fructose portion of a sucrose molecule||very stable with high-temperature cooking|
|Lactitol||2.0||40%||GRAS||reduction of the glucose portion of lactose||due to low sweetness, often combined with artificial sweeteners.|
|Maltitol||2.1||90%||GRAS||the hydrogenation of maltose||the sugar alcohol tasting closest to sugar|
|Mannitol||1.6||50%||food additive4||the hydrogenation of mannose||found in algae, mushrooms and trees; an isomer of sorbitol|
|Sorbitol||2.6||60%||GRAS||the hydrogenation of glucose||naturally occurs in fruits and vegetables|
|Tagatose5||1.5||90%||GRAS||mirror-image reconfiguration of lactose||not a true sugar alcohol, but has all the same traits: reduced calories; not as sweet as sugar; and GI side-effects|
|Xylitol||2.4||90%||food additive||extracted from birch tree pulp||also known as wood sugar; found in straw, corn cobs, bark, fruits and vegetables|
Substituting sugar alcohols for sugars and starches will reduce calories for a given food. The problem I foresee is the same thing that happened in the low-fat era - counting fat, but not calories failed. Most people on low-carbohydrate diets only track those carbs that a given diet says "count," forgetting about the calories involved. With more low-carbohydrate foods available, people will be able to eat more calories before they reach their daily carb limit. I know it is not politically correct, but this author still feels that "He who eats more calories will gain more weight."
In part 2 of this series, I'll review artificial sweeteners.
- Ensminger AH, Konlande JE, Robson JRK. Encyclopedia of Foods and Nutrition. Boca Raton, Florida: CRS Press, 1995.
G. Douglas Andersen, DC, DACBSP, CCN
Click here for previous articles by G. Douglas Andersen, DC, DACBSP, CCN.