Sorbitol and the Sugar Alcohols: Not Alcohol

Sugar alcohols set off an alarm they do not deserve. The word 'alcohol' in their name describes a shape, not an intoxicant, and none of them will make you drunk under any circumstances.

Sorbitol, mannitol, maltitol, xylitol, erythritol, isomalt. They are in sugar-free gum, mints, diabetic confectionery, toothpaste, cough syrup and a growing share of low-sugar products. And they all carry a word that stops people.

The word is a chemistry classification, and understanding why clears the whole category at once.

Why they are called alcohols

In chemistry, an alcohol is any molecule with a hydroxyl group — an oxygen bonded to a hydrogen — attached to a carbon. That is the entire definition. It is a structural label, and it covers an enormous range of substances with nothing else in common.

Ethanol, the intoxicating alcohol in beer and wine, is one member of this family. So is menthol. So is cholesterol — the 'ol' at the end is the same naming convention. So is glycerol, and so are the sugar alcohols.

How they are made

Almost all commercial sugar alcohols are produced by hydrogenation — adding hydrogen to a sugar under pressure with a metal catalyst, usually nickel or ruthenium. The feedstock is a plant sugar or starch:

• Sorbitol — from glucose, usually corn starch.
• Maltitol — from maltose, usually corn or wheat starch.
• Mannitol — from fructose or seaweed; also produced by fermentation.
• Xylitol — from xylose, traditionally birch and now usually corn cobs.
• Erythritol — the exception: produced by yeast fermentation of glucose. A yeast is involved, but the product is erythritol rather than ethanol, and this is not an alcoholic fermentation.
• Isomalt — from sucrose, usually beet sugar.

No animal input in any of these. The catalyst is a metal, the feedstock is a plant, and the product is a modified sugar.

The scholarly position

Settled and not controversial. The prohibition concerns khamr — intoxicants — and the operative property is intoxication. A substance that cannot intoxicate at any quantity is not covered, whatever its chemical classification.

This is the same reasoning that resolves several other cases in this series: lactic acid is a fermentation product but not an alcoholic one; citric acid is grown on a mould but purified from it; vanilla extract's ethanol is treated by most as a removed carrier at trace level. The principle being applied is consistent — the ruling follows the property that the prohibition is about.

The E numbers

• E420 sorbitol — E421 mannitol — E965 maltitol
• E966 lactitol — E967 xylitol — E968 erythritol — E953 isomalt

All plant-derived, all permissible. Lactitol is made from lactose and therefore has a dairy origin, which is permissible, though its lactose may trace back through cheese-making in the same way whey does — a second-order point rather than a practical obstacle.

What to check instead

In the products where sugar alcohols live, the questions that do arise are elsewhere:

• Gelatin in sugar-free gummies and chewable supplements.
• Glycerin in toothpaste, syrups and chewy confectionery — tallow or vegetable, unstated.
• Carmine in pink and red sugar-free sweets.
• Flavourings, particularly in gum and mints, where alcohol-based carriers are common.
• Gum base itself — a proprietary blend that can include stearic acid and glycerin derivatives, and is one of the least transparent ingredient declarations in food.

The digestive footnote

Worth stating because it is the real-world consequence people encounter. Sugar alcohols are incompletely absorbed and ferment in the large intestine, which causes bloating, wind and a laxative effect at moderate doses. Sorbitol and maltitol are the worst offenders; erythritol is largely absorbed before it gets there and is much better tolerated.

This is why sugar-free sweets carry a warning about excessive consumption. It is a genuine effect and nothing to do with the word 'alcohol'.

How we treat it

All the sugar alcohols pass our screen. The products they appear in are read for gelatin, glycerin, carmine and flavour carriers as usual — which is to say, the screen looks past the alarming word to the quiet ones.