When adding new sugar free sweets on the Sweets Without site we always put the ingredients and make sure that any allergens are highlighted as bold.text.
Lecithin in sugar free sweets
Soya Lecithin is a common ingredient in some sugar free sweets, like those that contain chocolate and toffees. The reason for using a Lecithin is that it enables two liquids that would not normally mix together make a stable mixture (emulsion). This is much like how washing up liquid works enabling the oil on the plate to be washed off into water. In the food context it helps chocolate maintain its silky smooth texture. Though soya is the most common source of Lecithin it can also be obtained from egg yolk and sunflowers.
Though Soya Lecithin contains no soya protein the recommendation is that those people allergic to soya stay clear of it. This is because some people who are very sensitive to soya could have a reaction to soya lecithin.
Like all ingredients there is controversy with some people claiming it is added to tea just to extend the life while other claims it makes the tea better.
As a food ssupplement
Soya lecithin is also sold as a heath food supplement. There are those who claim that it can help in corollary heart disease by stopping the build up of cholesterol in the arteries. Like all such claims I would take it with a pinch of salt. but then I remember that too much salt is bad for you! Even if these claims were true, the amount of Lecithin in sweets is so small as to have no health benefit.