Sugar vs. Sugar Alcohol: What's the Difference?

Sugar is a type of simple carbohydrate that tastes sweet and is found naturally in foods such as fruits, vegetables, grains, and dairy products.

Examples of natural sugars include:

• Sucrose
• Fructose
• Galactose
• Glucose
• Lactose
• Maltose

Sugar alcohols or polyols are not the same as sugar, although they are typically derived from sugar. They are naturally found in some fruits and vegetables and are often used to sweeten chewing gum, candies, medications, and toothpaste.

Examples of common sugar alcohols include:

• Xylitol
• Erythritol
• Mannitol
• Sorbitol
• Maltitol
• Lactitol

Sugar alcohols have a slightly distinctive flavor and different sweetness levels:

• Xylitol is 100% as sweet as sugar
• Erythritol is 60%-80% sweeter than sugar 
• Lactitol is 30%-40% sweeter than sugar

Calories

Sugar alcohols have fewer calories than sugar and are often used as lower-calorie sugar substitutes.

One gram of sucrose contains 3.9 calories. Most sugar alcohols (such as xylitol and sorbitol) contain roughly half that amount or about 2 calories per gram. Erythritol, at only 0.2 calories per gram, is the lowest-calorie sugar alcohol.

Digestion

When sugar is digested, it splits into glucose and fructose, which are then absorbed through the small intestine. The glucose remains in the body to be used for energy or stored as fat or glycogen for later use, whereas the fructose travels to the liver to be converted to fat.

Sugar alcohols are digested differently in the body. They move to the big intestine instead of the small intestine and are later broken down by gut bacteria and ferment there.

Erythritol is an exception. Erythritol enters the bloodstream through the small intestine and is absorbed there without being metabolized. About 90% is eliminated through urine.

Impact on blood sugar

The glycemic index (GI) calculates the rate at which a type of food will cause the blood sugar level to rise. 

Pure glucose has a score of 100. Sugar or sucrose has 65. All sugar alcohols have a score of 35 or less. Erythritol has a score of 0.

Therefore sugar alcohols may be a good sugar alternative for people with diabetes since they have less significant effects on blood sugar levels.

Oral health

Sugar causes cavities by feeding bacteria in your mouth that produce enamel-damaging acids.

Sugar alcohols do not have the same effect and may even inhibit the growth of bacteria that can cause tooth decay. This is why erythritol and xylitol are often used to sweeten sugar-free gums or toothpaste.

Sugar alcohols impart the sweetness of sugar without the negative metabolic effects. They are a good option for people with diabetes since they do not cause blood sugar spikes.

However, sugar alcohols are not as well absorbed by the body and can cause side effects such as stomach pain, bloating, and diarrhea.