The Nature of Polyols

Polyols, also known as sugar alcohols, are a type of low-digestible carbohydrate used widely as sugar substitutes. They’re neither true sugars nor alcohols chemically, but they share some structural features of both.

Chemical Structure and Properties

• Polyols are hydrogenated forms of sugars, where the carbonyl group (C=O) of a sugar (like glucose or fructose) is reduced to a hydroxyl group (–OH).

• This change results in a sweeter-tasting, lower-calorie compound that the body absorbs more slowly and incompletely.

• Common examples:

  • Sorbitol

  • Xylitol

  • Erythritol

  • Maltitol

  • Mannitol

  • Isomalt

  • Lactitol

Where Are Polyols Used?

• Sugar-free gums, candies, and mints – they make use of the cooling effect.

• “Low-carb” and diabetic-friendly foods – reduced sugar foods generally

• Toothpaste and mouthwash (due to non-cariogenic properties)

• Baking and processed foods as sweeteners and texture enhancers

Benefits

• Fewer calories: Typically 1.5–3 kcal/g vs. 4 kcal/g for sugar.
  (Erythritol has nearly zero calories.)

• Lower glycemic impact: Good for diabetics because they cause minimal blood sugar spikes.

• Tooth-friendly: Unlike sugar, polyols don’t feed oral bacteria, reducing the risk of cavities.

• Cooling effect: Especially noticeable with erythritol and xylitol due to their endothermic dissolution.

The Cooling Effect From Polyols And How It Compares With Sugar (Sucrose)

The cooling sensation that sometimes occurs when sugars or certain sugar alcohols dissolve on the tongue is due to an endothermic dissolution process.

Here’s how it works:

When a substance dissolves in water (like your saliva), it can either release heat (exothermic) or absorb heat (endothermic). Some sweeteners, particularly sugar alcohols like xylitol, erythritol, or mannitol, dissolve endothermically. That means:

• They absorb heat from the surroundings—in this case, from your mouth.

• This heat absorption lowers the temperature locally, producing a cooling sensation.

Important clarifications:

• Table sugar (sucrose) has a very slight endothermic dissolution, but not enough to produce a strong cooling effect.

• Erythritol and xylitol, often found in sugar-free mints and gums, produce a noticeable cooling effect due to their strongly endothermic dissolution.

So, if you’re feeling a strong cooling effect when eating something sweet, you’re likely tasting sugar alcohols, not regular sugars.

Side Effects

• In large amounts, polyols can cause gastrointestinal issues, like:

  • Bloating

  • Gas

  • Diarrhea
    This is because they’re poorly absorbed in the small intestine and fermented by bacteria in the colon.

This is why many polyol-containing products carry a warning like: “Excessive consumption may cause a laxative effect.”

Comparison of Common Polyols

 Summary

Polyols are useful sugar alternatives that provide sweetness with fewer calories and health benefits like dental protection and low glycemic response. However, moderation is key due to their potential to cause digestive discomfort.