What Are Sugar Alcohols?

Irene Berman-Levine, PhD, RD
August 17, 2005

This is the 15th article we've published by Dr Irene Berman-Levine. It's taken from one of her newsletters, "Dr Irene's Nutrition Tidbits", and is a follow-up to her article "Sugar Substitutes" (see first link below). You can subscribe to this newsletter by clicking on: http://www.healthandage.org/Home/gm=22
Robert Griffith, Editor.

A little sugar is not the villain that some think

A teaspoon of sugar is only 16 calories and 4 grams of carbohydrate. Unfortunately most people's sweet tooth demands more than a teaspoonful. American eats the equivalent of about 20 teaspoons of sugar a day, according to the Continuing Survey of Food Intakes by Individuals. Nearly 60% of this intake is from corn sweeteners used heavily in sodas and other sweetened drinks. Another 40% is from sucrose (table sugar), and a small amount comes from other sweeteners, such as honey and molasses. The demand for foods with lower calories and the same sweet taste has created a multimillion dollar search for new sweetening agents.

The use of some sugar substitutes is controversial. Although the sugar substitutes on the market have been approved by the FDA, there are many internet discussions and rumors as to their safety. In this article I do not have room to address safety concerns, but I will in future newsletters.

There are many sweetening agents, but this article will just describe sugar alcohols. Sugar alcohols, also know as polyols, include sorbitol, mannitol, xylitol, lactitol, isomalt, maltitol, and hydrogenated starch hydrolysates (HSH). They are given the name sugar alcohol because part of their structure resembles sugar and part is similar to alcohol. Sugar alcohols do not contain ethanol, which is found in alcoholic beverages. In other words, you won't get drunk from your sugar-free chocolates.

Sugar alcohols occur naturally in small amounts in foods. For example, mannitol is a sugar alcohol naturally found in pineapples, olives, asparagus, sweet potatoes and carrots. Use in large amounts, such as the concentration if you eat too many sugar-free candies, causes GI cramps and diarrhea.

Most sugar-free foods are not meant for weight reduction because their calories are almost the same as other food products. The sugar alcohols do provide slightly lower calories (1.5 to 3 calories per gram) than sugar (4 calories per gram), and they don't cause tooth decay like sugar does. The calorie difference is compensated because more has to be used for the same sweetness. For example, mannitol has 50-70% of the relative sweetness of sugar. Sugar alcohols do have the advantage of slower absorption and require less insulin to break down, which decreases the impact on blood sugar for individuals with diabetes.

Sorbitol

Sorbitol is found naturally in fruits and vegetables and is partially responsible for the laxative effect of some fruits. Commercially it is usually produced from corn syrup. Sorbitol is only 50-60% as sweet as sugar which means twice as much must be used to deliver a similar amount of sweetness to a product. It only contains about 2.6 calories per gram though (compared to sugar's 4 calories/gram) so the actual calories your body extracts from a sorbitol sweetened food is usually similar to its sugar-sweetened counterpart.

Xylitol

Ever seen sugar-less gum sweetened with xylitol? Xylitol occurs naturally in many fruits and vegetables and is even produce by the human body during normal metabolism. Since it has a sweet taste but does not promote cavities, it's a popular choice for some sugar free gums. It's sometimes called "wood sugar" because it's produced commercially from plants such as birch and other hard wood trees and fibrous vegetation. Xylitol has the same sweetness and bulk as sucrose with one-third fewer calories (2.4 cal/gram)

Lactilol

Lactitol is used in the new sugar-free chocolates. It is frequently used in sugar-free foods because its taste and solubility (how it dissolves) resemble sugar. These foods are not designed for weight reduction and may be similar in calories to their sugar counterparts because lactitol is only about 30-40% as sweet as sugar. Even though you have to use more than twice as much to get the same sweetening power, the net calories are about the same as sugar products because it has only about half the calories as sugar (about 2 calories/gram).

Isomalt

Isomalt is 45-65% as sweet as sugar, but again provides less calories per gram than sugar (2 calories/gram). Even though you have to use more to get the same sweetening power as sugar, it is often used in sugar-free hard candy because it doesn't lose its sweetness or break down if the cooking process requires high heat and it absorbs little water. Discovered in the 1960s, isomalt is made from sucrose and looks much like table sugar. It's a mixture of two other sugar alcohols, mannitol and sorbitol.

Mannitol

Mannitol is an isomer (meaning it has the same formula but different structure) of sorbitol. It's about 50% as sweet as sucrose. You are probably most familiar with it when you notice a powder on your chewing gum. It's used to prevent the gum from sticking to manufacturing equipment and wrappers.

Maltilol

Maltitol is a sweetener made from maltose, a carbohydrate found in starch. It is 75-90% as sweet as sugar but contains only 2.1 calories per gram. It is used in sugarfree hard candies, chewing gum, chocolate-flavored desserts, baked goods, and ice cream. Because of its ability to give a creamy texture to foods, it may also be used to replace fat when trying to create low fat products.

I'm sure you feel like you need a drink after reading about so many sugar alcohols! At least when you see the names on the labels you'll be able to say "uh-oh, this contains sugar alcohol - I'd better control my portion!"

Source

• I Berman-Levine PhD, RD. "Dr Irene's Nutrition Tidbits" Newsletter published in 2004 by HealthandAge.com.

Related Links
Sugar Substitutes
Dr Irene's Nutritional Tidbits
The Fast-Food Habit
Dr. Irene's Five Pitfalls of Dieting

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