Lactitol

Lactitol is made from lactose, and it is prescribed as a laxative in its own right - which tells you plainly what a food-sized dose does. It is the one polyol whose medical use and food use are the same mechanism at two different doses.

Lactitol is a polyol made from lactose, and it is prescribed as a laxative in its own right - which tells you plainly what a food-sized dose does.

Lactitol carries a trace of nickel for a reason written into the law that governs it. E 966 is made by CATALYTIC HYDROGENATION and the catalyst is nickel - the regulation says so in its own text - so its purity criteria carry a nickel limit. That is a legal CEILING and not a content: what a given batch actually holds is not published, and the exact figure for this one is not quoted. But a ceiling exists because a trace is expected.

Lactitol is made from lactose, which is exactly why its answer here deserves an explanation rather than a shrug. The hydrogenation that turns lactose into lactitol leaves no lactose behind, and the law says as much in the place it counts: Annex II requires 'milk and products thereof (including lactose)' to be declared as an allergen, and names two exceptions - whey used for alcoholic distillates, and LACTITOL. An exemption from declaring is a judgement that the process removed what mattered, not a measurement, but it is a judgement made in law and it is specific to this substance.