Lecithins are natural. They belong to the class of phospholipids. It is not a molecule but a group of molecules whose fatty acid composition varies. Lecithins are mainly extracted from soybeans. Their use does not seem to present any risk, except for people who are allergic to soya. Indeed, although this allergy is linked to soy proteins, it seems preferable that sensitive people also avoid consuming soy lecithins, because the possibility of their contamination by soy protein fractions cannot be completely excluded.
Very many food categories (including baby food).