SUGAR ALCOHOL
POLYOL
On my quest to discover all sweeteners sold on store shelves, I found an astonishing number of polyols. Also known as sugar alcohols, they’re neither sugars nor alcohols—but they do have unique properties that set them apart. So, what exactly are polyols, and how do they stack up against other sweeteners? Let’s take a closer look.
WHAT IS A SUGAR ALCOHOL?
Sugar alcohols, also known as polyols, are neither sugars nor alcohols — they're actually sugar-free sweeteners. Like table sugar, polyols are carbohydrates, but they provide fewer calories because they resist digestion to varying degrees. Some are slowly absorbed, others only partially metabolized, and one passes through the body mostly intact.
From chemistry class, polyol means "containing many -OH groups" (hydroxyl or alcohol group). This explains why polyols' names end in -ol, such as in sorbitol, xylitol, mannitol, maltitol, and isomaltitol.
Sugar alcohols are ideal for reducing sugar while maintaining a sugar-like texture in your recipes. As bulk sweeteners, they do more than just add sweetness—they also contribute weight and volume, much like sugar. This sets them apart from bulk-free sweeteners, which are highly concentrated and used solely for sweetness.
TYPES OF POLYOLS
The most widely used polyols in sugar substitutes include:
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Erythritol
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Xylitol
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Sorbitol
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Mannitol
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Isomalt
How sweet are polyols?
Except for xylitol, which matches sugar in sweetness, most polyols are only mildly sweet. So, manufacturers often blend them with high-intensity sweeteners such as stevia, monk fruit, or sucralose.
Are polyols natural or artificial sweeteners?
The FDA defines natural ingredients as those that exist in nature AND are derived from natural materials. However, it acknowledges that some ingredients that exist in very small amounts in nature must be "manufactured artificially" to be produced in large scale. The FDA still considers these “natural”, but for clarity, here at WhatSugar we refer to them as synthetic.
To explain this, the FDA uses vitamin C (ascorbic acid) as an example. It can be derived from an orange or artificially produced via fermentation, but the final ingredient is identical. The same applies to some polyols like erythritol, which naturally occurs in some foods but only in minuscule amounts. So, it's commercially produced through fermentation from corn.
Note that synthetic is not the same as artificial. Vitamin C made via fermentation would not be considered artificial as it’s indistinguishable from the vitamin C found naturally in fruits. Learn more about natural vs synthetic vs artificial HERE and HERE.
Not all polyols are found in nature, but all are synthetically made from sugars:
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Natural polyols (per FDA definition) include erythritol, sorbitol, xylitol, and mannitol because they're found in nature AND derived from a natural source. These can legally be labeled as “natural,” though at WhatSugar, we categorize them as synthetic due to their manufacturing process.
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Artificial polyols include isomalt and maltitol because even though they're made from natural materials, they're not found in nature.
Most polyols are derived from glucose or glucose syrups (from starch), while others come from sucrose (sugarcane or sugarbeet), lactose (milk), or xylose (wood).
POLYOLS' DIGESTION & METABOLISM
How do polyols behave in our bodies?
Polyols provide fewer calories than sugar because they resist digestion—some to a greater extent than others. Here's how our bodies process them:
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Absorption in the small intestine:
They're partially absorbed in the small intestine, but to different degrees. For example, erythritol has a fast and partial aborption (60 to 90 % of ingested erythritol), while xylitol is absorbed slowly and in smaller amounts (only 1/4 of the ingested amount).
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Metabolism:
Some of these sweeteners are slowly digested, while others undergo only partial metabolism. For instance, erythritol isn't metabolized — though a small portion passes intact into the large intestine. Since erythritol isn't converted into glucose, it have no effect on blood sugar levels.
On the other hand, xylitol is slowly absorbed and converted into glucose, so it does not cause a sudden increase in blood sugar.
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Fermentation in the large intestine:
The portion that is not digested by gut enzymes reaches the large intestine, where they may be fermented by the microbiota (healthy bacteria in the gut) or excreted in feces.
This fermentation has both drawbacks and benefits. It can cause digestive issues such as bloating, flatulence, and diarrhea. However, they may act as prebiotics, by stimulating the growth and activity of gut microbes.
If too much polyol reaches the large intestine, it may act osmotically by drawing water from the body, resulting in loose stools.
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How come erythritol is not digested and still have calories?
Even though we cannot metabolize erythritol, bacteria in the lower digestive tract can. The low caloric value attributed to eryhtritol is because microbes metabolize them, and we obtain their energy indirectly. This is why erythritol is the only polyol that can be labeled as "zero-calories".
What are polyols' calories?
Erythritol is the polyol with the lowest caloric value — 0.2 to 0.4 calories per gram. Since its caloric value per gram is very low, the Food and Drug Administration (FDA) regulations for nutrition labels rounded it to zero. To compare with other polyols: Isomalt—2.0, xylitol—2.4, maltitol—2.1, sorbitol—2.6, mannitol—1.6.
Are all polyols sugar-free?
Yes. While all polyols are sugar-free sweeteners, they're not calorie-free and can have different effects on blood sugar levels. For example, maltitol has a higher glycemic index than other polyols, meaning it can cause a more significant increase in blood glucose. On the other hand, erythritol is an exception — it's calorie-free and has zero glycemic impact.
POLYOLS' GLYCEMIC INDEX
Do polyols spike blood sugar?
When it comes to the effect on blood sugar levels, polyols may act in one of two ways:
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Partially or slowly digested
These polyols do not cause a sudden increase in blood glucose. For example, xylitol and sorbitol break down slowly during digestion, releasing glucose slowly in the bloodstream.
The glycemic index (GI) of polyols indicates their potential to raise blood glucose levels. Pure glucose has an arbitrary GI of 100 (see image below), and so, most polyols have a low GI: -
Not digested at all
Eryhtritol is an exception among polyols as it is absorbed but not metabolized into glucose. Having no effect on blood glucose, Erythritol GI = 0.
For the glycemic index of common sugar alcohols, you can check HERE or the University of Sydney Glycemic Index database.
POLYOLS' CARB COUNT
Counting carbohydrates can be confusing, especially when you realize that not all carbs affect blood sugar the same way. I get a lot of questions about how to count sugar alcohols, so here’s what you need to know.
Do polyols count as carbs?
Yes, polyols are technically carbohydrates and are included in the "total carbohydrates" section of the Nutrition Facts label.
Do polyols count towards net carbs?
Net carbs refers to carbohydrates your body actually digests and converts into glucose, which raises blood sugar. But not all polyols behave the same way (see explanation above), so they are counted differently:
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Partially Digested Polyol – Count HALF of the amount ✔
These polyols are partially absorbed and converted into glucose, so only about half of their carb content affects blood sugar. It includes
xylitol, sorbitol, mannitol, and isomalt.
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Non-Digestible Polyols – Count as 0 net carbs ✖️
Erythritol is the only polyol that is not converted into glucose, not raising blood sugar, so it does not count toward net carbs.
Bottom Line:
When calculating net carbs, subtract erythritol completely but count half the carbs from xylitol, sorbitol, mannitol, and isomalt.
HOW MUCH POLYOL IS TOO MUCH?
How do I track sugar alcohols?
Read the Nutrition Facts label if you want to monitor erythritol or any other polyol in your diet:
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Start by checking the list of ingredients
If erythritol is present, confirm if it contains other sugar alcohols, such as xylitol, mannitol, sorbitol, isomalt, or maltitol. Currently, erythritol is way more popular than all the other sugar alcohols, so a much more common ingredient.
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Move on to the nutrition facts label
Under “Total Carbohydrates”, look for "Sugar Alcohols." If no other sugar alcohol is present, the amount listed is the total amount of erythritol PER SERVING. Note that by law, food manufacturers are not required to list the amount of sugar alcohols. However, they must include it if they make claims like sugar-free and no-added-sugar, which are common in zero-calorie, low-carb, and keto foods.
What is considered an excessive amount of sugar alcohol?
Among polyols, sorbitol and mannitol are the most likely to lead to adverse digestive issues, while erythritol tends to cause the least. For sorbitol, the FDA suggests that over 50 grams of sorbitol per day is considered excessive, in terms of potential digestive side effects. For mannitol, the limit is 20 grams.
Erythritol is generally better tolerated, with a 150-lb person able to consume up to 68 grams (or 5.5 tablespoons) without gastric discomfort. However, the same and lower doses consumed by simply dissolving it in water or in dry form after fasting might result in laxation and other digestive issues.
Individual tolerance varies – some people are more sensitive to these sweeteners than others.
POLYOLS' PROS AND CONS
Advantages of Sugar Alcohols:
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Sweet taste – Provide sweetness while helping cut back on sugar
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Lower in calories – Offer reduced caloric intake compared to sugar
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Bulking properties – Add weight and volume to foods, impacting mouthfeel and texture, as regular sugar does
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Digestive health benefits – May act as prebiotic.
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Non-cariogenic – Cannot be fermented by bacteria that cause cavities. Sugar alcohols are referred to as Noncariogenic Carbohydrate Sweeteners by the Food and Drug Administration. Labels may carry health claims such as "does not promote," "may reduce the risk of," "useful in not promoting" dental caries. Unique to xylitol is the cariostatic or anti-cavity effect as it starves harmful mouth bacteria, inhibiting their growth and activity.
Disadvantages of Sugar Alcohols:
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Do not brown or caramelize
Polyols do not brown or caramelize baking goods like table sugar components do (glucose & fructose) as they do not have an exposed carbonyl (C=O) group necessary for browning reactions.
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Have a cooling effect
Polyol crystals create a cold sensation when they dissolve in the mouth. This happens because they absorb energy from its surroundings (your mouth) as they dissolve, similar to the feeling of sucking on a mint—but without the mint flavor. While all polyols have a cooling effect, erythritol produces the strongest and longest-lasting sensation.
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Often associated with adverse digestive issues
The portion of polyols that is not digested by gut enzymes, reaches the large intestine intact and may be fermented by microbiota.
The consequence of too much undigested polyols reaching the large intestine is adverse gastrointestinal effects such as discomfort, bloating, stomach rumble, flatulence, and diarrhea. Individual tolerance varies – some people are more sensitive to polyols than others. Stomach issues are more common in unaccustomed consumers as adaptation may happen over time.
All polyols are FODMAP carbohydrates, an acronym for Fermentable Oligo-, Di-, Mono-saccharides, and Polyols. The term was coined to designate carbohydrates associated with negative digestive effects.
The least effects occur with erythritol, and the worst happen with sorbitol and mannitol. By law, products with sorbitol and mannitol must include a warning on their label stating "excess consumption may have a laxative effect".
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