Overview
About Lactitol
Lactitol is made by hydrogenating lactose, and the name puts people off for the wrong reason.
It contains no lactose. Our data grades it clean on lactose and clean on dairy protein, and EU law agrees: lactitol is one of the very few milk-derived ingredients specifically exempted from allergen declaration under Regulation 1169/2011. What it actually is, is a polyol, graded high FODMAP and high polyol. It is potent enough that a 20 gram dose is licensed as a prescription laxative for chronic constipation. That is the honest dose response for anyone eating sugar-free chocolate or baked goods: the amount that treats constipation is the amount that can hide in an afternoon of snacking.
Sensitivities
How Lactitol scores
Watch for
What trips people up
- Graded high on FODMAPs and polyols. No human enzyme splits the bond, so lactitol arrives in the colon whole, holds water osmotically and then gets fermented.
- The dose response is unusually well documented because lactitol is a licensed medicine. Around 20 grams a day is the therapeutic laxative dose for chronic idiopathic constipation, so several sugar-free sweets or a large bar of sugar-free chocolate is not a trivial amount.
- It carries no lactose and no milk protein, so lactose intolerance and cow milk protein allergy are not the mechanism. If lactitol bothers you, it is the polyol doing it, not the dairy origin.
- Graded poorly for SIBO fermentation, which matters more than the raw dose if you have small intestinal bacterial overgrowth.
- It is still milk-derived in origin even though it needs no allergen declaration. Strict vegans and people avoiding all dairy-sourced ingredients on principle will want to know that, because the label will not tell them.
Diet fit
Where it fits
Swap ideas
More alternatives
FAQ
Common questions about Lactitol
Does lactitol contain lactose?
No. Lactitol is manufactured from lactose by hydrogenation, which permanently converts the glucose end of the molecule into sorbitol. The resulting compound is a different substance and contains no lactose. Our data grades it clean on both the lactose and dairy protein columns.
Is lactitol safe if you are lactose intolerant?
Lactase deficiency is irrelevant to lactitol, because there is no lactose left to digest. The catch is that lactitol causes a very similar set of symptoms by a different route: it is a polyol, so it is malabsorbed and ferments in the colon. Someone who avoided dairy and then reacted to a sugar-free chocolate is often blaming the wrong ingredient.
Is lactitol low FODMAP?
No, it is graded high FODMAP and high polyol and should be excluded during a low FODMAP elimination phase. It belongs in the same category as sorbitol, mannitol, maltitol and isomalt rather than with the digestible sugars.
Why does lactitol cause diarrhoea?
Two mechanisms stack. Undigested lactitol is osmotically active, so it holds water inside the bowel, and colonic bacteria then ferment it into gas and short chain fatty acids that speed transit. That combination is precisely why it works as a prescription laxative, and why an unintended dose from confectionery produces the same effect.
References
Read the background
Ratings reflect the Triggerbites ingredient database and may vary with portion size and preparation.