FOOD FOR THOUGHT
SUGAR ALCOHOLS (POLYOLS) QandA: OUR EXPERTS ANSWER YOUR QUESTIONS
Prof Jennie Brand-Miller and Dr Alan Barclay answer 7 of the most common questions we are asked about sugar alcohols.
WHAT ARE SUGAR ALCOHOLS (POLYOLS)?
Erythritol, glycerol, hydrogenated starch hydrolysates, isomalt, lactitol, maltitol, mannitol, sorbitol and xylitol are sugar alcohols. They are a type of carbohydrate. Their somewhat confusing name comes from their chemical structure with its characteristics of both sugars and alcohol. But they don’t actually contain sugars nor do they contain the type of alcohol found in beer, wine or spirits. They are sweet but, except for xylitol, generally much less sweet than sucrose, which is why food and beverage manufacturers often combine them with intense sweeteners such as stevia in foods and beverages.
WHERE DO YOU FIND THEM?
Food manufacturers use sugar alcohols as reduced-calorie (kilojoule) sugar substitutes to sweeten “diabetic friendly”, sugar free and no added sugars products including chewing gum, candy (lollies), ice cream, dairy desserts, yoghurts, baked goods such as cakes and cookies, and fruit spreads and jams. They also add them to tabletop and spoonable or pourable high-intensity sweeteners such as stevia as bulking agents. You’ll also find them in toothpastes, mouthwashes, breath mints, cough syrups or drops and throat lozenges in the pharmacy aisles. Apart from xylitol, you’ll be very unlikely to see them on the supermarket shelf as they are not commonly used as ingredients in home cooking.
WHERE DO THEY COME FROM?
Most sugar alcohols are produced in commercial quantities for the food industry from various sugars or starches. However, they do occur naturally in many plants. For example:
- Erythritol is found in small amounts in grapes, melons and mushrooms and in fermented foods such as wine, beer, sake, cheese, and soy sauce.
- Sorbitol occurs naturally in many fruits and berries. It was first “discovered” way back in 1872 in the berries of Sorbus aucuparia – mountain ash.
- Xylitol is found in birch bark and in the dietary fibre of many fruits and vegetables.
ARE THEY LIKE ARTIFICIAL SWEETENERS?
No. They are quite different. Sugar alcohols (polyols) are found in nature and are nutritive sweeteners with an average of 2 calories or 8 kilojoules per gram (versus the 4 calories or 17 kilojoules per gram of sugars and starches). Artificial sweeteners like saccharin and sucralose on the other hand are non-nutritive intense sweeteners with zero calories/kilojoules and come directly from the chemistry lab.
WHAT’S THE UPSIDE OF CHOOSING FOODS SWEETENED WITH SUGAR ALCOHOLS?
They have a couple of advantages over sugars (sucrose, glucose, fructose, maltose, etc.)
- First, they may have less effect on blood glucose (blood sugar) because the body treats them as dietary fibre, which means they are slowly and incompletely absorbed from the small intestine into the bloodstream. See Perspectives below for GI values.
- And they are “tooth friendly.” They don’t provide energy for plaque bacteria in the mouth so don’t cause cavities. FDA has approved the use of a “does not promote tooth decay” health claim in labelling for sugar-free foods that contain polyols, and in other parts of the world they may be labelled “safe for teeth.”
WHAT’S THE DOWNSIDE OF CHOOSING FOODS SWEETENED WITH SUGAR ALCOHOLS?
Some (isomalt, lactitol, maltitol and maltitol syrup, mannitol, sorbitol, and xylitol) may have a laxative effect and/or cause bloating, rumbling, gas, or diarrhea if you consume them in large amounts.
- Foods that contain more than 10 grams of lactitol, maltitol, mannitol, and xylitol per 100 grams, or more than 25 grams of erythritol, sorbitol, or isomalt per 100 grams, carry warning statements about the possible laxative effect on their labels. These products can be a particular problem for children and adolescents because of their smaller body size.
- In Europe, the labelling of foods containing more than 10 per cent added polyols must include the advisory statement “excessive consumption may produce laxative effects.” EU approval for erythritol excludes its use in beverages, as there is a concern that the laxative threshold value may be exceeded when it is consumed this way, especially by young people.
- Those following a low-FODMAP diet due to digestive conditions such as irritable bowel syndrome (IBS) may need to avoid them. (FODMAPs are sugars in foods that are poorly absorbed by the gut. The “P” stands for polyols.
HOW CAN I MONITOR MY INTAKE OF SUGAR ALCOHOLS?
Products that contain sugar alcohols (polyols) will list them in the ingredients (in descending order by weight). However, you’ll be hard pressed to find out exactly how much you are getting per serving or per 100 grams because you won’t find any hard data in the carbohydrates section of the nutrition facts panel in most parts of the world.
In the USA, food manufacturers may voluntarily list the amount in grams per serving of sugar alcohols on the Nutrition Facts Label (under Total Carbohydrate). They may also list the name of a specific sugar alcohol if only one is added to the food. However, if a statement is made on the package labelling about the health effects of sugar alcohols or sugars (when sugar alcohols are present in the food), food manufacturers are required to list sugar alcohols.
- The Ultimate Guide to Sugars and Sweeteners (Includes entries for individual sugar alcohols/polyols)