Posted on 11 Aug 2015 04:12
If you've ever eaten sugar free candies, especially hard candies marketed to diabetics, then you may have had sugar alcohols. They are sweeteners like sorbitol, mannitol, malitol, xylitol, lactitol, and isomalt. Besides hard candies, they are also used in sugarless gum, cookies, and jams and jellies.
Sugar alcohols are also called polyols. They are alternative sweeteners like artificial or nonnutritive sweeteners, but they are not actually nonnutritive. They are very common in dietetic food products.
Do Sugar Alcohols Contain Alcohol?
Despite the name, sugar alcohols do not contain ethyl alcohol (ethanol), the kind of alcohol found in alcoholic beverages like beer, liquor, or wine. The reason they are called sugar alcohols is because they have a structure that makes them part of the alcohol family. They have absolutely no intoxicating effects.
Do Sugar Alcohols Have Zero Calories?
When sugar alcohols are used in foods, the foods are called sugar-free. However, this does not make them calorie-free, as sugar alcohols do contain calories. They do provide less caloric-energy than sugar, however, while still being sweet.
You will often read that sugar alcohols have the same amount of calories as sugar. This is actually true. But, they are not absorbed or processed by the body as efficiently as sugar, on average, they end up imparting around 1.25 less calories than the same amount of sugar. This means that if one gram of sugar is 4 calories, 1 gram of sugar alcohol is 2.75 calories.
Why Are They Marketed to Diabetics
Diabetics shouldn't eat large amounts of sugar alcohols any more than they should eat large amounts of sugar. However, sugar alcohols are absorbed and processed more slowly, so some diabetics can handle a certain amount of them. They cause a lower glycemic response than sugar, making them safer for people with diabetics to enjoy a moderate amount of foods sweetened with them.
Why are Sugar Alcohols Considered Nutritive Sweeteners?
Although they are absorbed and processed more slowly, they are metabolized by the body. This makes them different from zero calorie sweeteners like aspartame or sucralose, which most of us call artificial sweeteners, but are also called nonnutritive sweeteners. Sugar alcohols, then are nutrtitive sweeteners. They actually exist naturally in some fruits and vegetables, particularly in stone fruits like peaches, plums, cherries, nectarines, etc.
How are Sugar Alcohols Made?
Although they occur naturally in, large amounts of them are produced for food use by hydrogenating sacharides. Most of these sacharides come from plants. Lactitol is made from lactose, the sugar in milk.
What's the Problem with Sugar Alcohols?
Since sugar alcohols cause a lower glycemic response and impart less caloric energy, they may be useful to decrease calories, or for diabetics or hypoglycemics to satisfy their sweet tooth. The disadvantage is the side-effects.
Large amounts of sugar alcohols can cause gastrointestinal symptoms such as gas, pain, and diarrhea (similar to a laxative). These side-effects are common and can be very severe. Both the United States and Canda require warning labels on foods using sugar alcohols, describing the laxative effect.
Most guidelines warn against having 50 grams or more of sugar alcohols to avoid the side-effect, but for some, as little as ten grams can cause the symptoms.
They Don't Promote Tooth Decay!
The advantages to diabetics or for weight-loss can be easily removed by the side-effects, especially for sensitive people. But they sugar alcohols have another advantage. Bacteria in the mouth doesn't metabolize sugar alcohols very readily either. They do ferment like other carbohydrates, but it is a slow process. A much smaller amount of acid is produced by the bacteria, and at a slower pace. It is the acids that degrade the enamel of our teeth. Less acid, less tooth-decay. So, sugar alcohols do not promote cavities, or dental caries, as much as sugar. For this reason they are called noncariogenic. This is why you will find them in chewing gum, breath mints, or anything that is meant to stay in your mouth for a while, and needs to be sweet. You won't actually be getting a large amount of sugar alcohols — not enough to cause symptoms, and the amount you do get won't cause cavities. The FDA allows manufacturers to say that products using these sugar alcohols to state that they do not promote tooth decay on labels.
If you are prone to getting cavities, sugar-free gums and mints using sugar alcohols probably are a good alternative. The small amounts are not likely to give you any symptoms, or cause you any harm.
How Are Sugar Alcohols Listed on Food Labels?
Sugar in foods must be declared on the nutrition facts panel if the food contains more than one gram. Even if the food contains less than one gram of sugar, but still contains some, it will show up in the ingredients listing. Remember that ingredients are listed by weight, so the earlier in the listing an item appears, the more the food contains of that item by weight.
Listing sugar alcohols or polyols on the nutrition facts panel, however, is voluntary, unless there is a claim made on the food label, or in other labeling, about sugar alcohol or sugars, and there are sugar alcohols present in the food. What this means is that if the front of the label says something like 'sugar free' and the food uses sugar alcohol, then the sugar alcohols must be listed in the nutrition facts panel.
If the food does list sugar alcohol on the nutrition facts panel, and more than one type of sugar alcohol is used in the food, the sum of the amounts of all the sugar alcohols is listed to the nearest gram. In this case, the words sugar alcohols will be used to describe them. But, if only one type of sugar alcohol is used, the manufacture may use the name of the particular sugar alcohol on the nutrition facts panel.
If the food contains less than one gram of sugar alcohols then the statement 'contains less than one gram' or 'less than one gram' may be used instead. If less than 0.5 grams are present, the amount can be listed as zero. But remember, this is only in the case of a claim about the sugar status of the product being made elsewhere on the label. Otherwise, it is voluntary. You may not know that a product contains sugar alcohols unless you read the ingredients. The laxative warning, as mentioned above, is only required on products containing more than 50 grams.
The definition of a sugar alcohol according to the FDA (which governs the labelling) is 'a sacharide derivative in which a hydroxil group replaces a ketone or aldehyde group, and is generally recognized as safe (GRAS).'
The table below gives and overview of individual sugar alcohols, with the approximate sweetness compared to sugar, the calories, and the uses.
Various Sugar Alcohols and Their Calories, Sweetness, and Uses
|Sugar Alcohol Type||Sweetness Compared to Sugar||Calories per Gram||Uses in Foods|
|Sorbitol||half as sweet||2.6||special dietary foods, eg. diabetic foods, candies, gums|
|Mannitol||0.7 times as sweet||1.6||bulking agent, chewing gums, candies, baked goods|
|Maltitol||0.9 times as sweet||2.1||candies, candy coatings, ice creams, bakery products|
|Xylitol||same sweetness||2.4||chewing gum, candies, drug products, oral health products eg. toothpaste and mouthwash|
|Isolmalt||half as sweet||2.0||candies, chewing gum, frostings, ice cream, baked goods, beverages, james, jellies|
|Lactitol||0.4 times as sweet||2.0||candies, chewing gum, frozen dairy desserts, frostings, baked goods, jams, jellies|
|Erythritol*||0.7 times as sweet||0.25||bakery fillings, cakes, cookies, chewing gums, milk drinks, and many other products|
You probably noticed that erythritol, the last sugar alcohol in the table above, is a bit different than the others. It contains next to no calories but has around 70% of the sweetness of sugar. It is a fairly new type that is produced using a fermentation process. the laxative effect is much less.