Marshmallows used to be a medicinal remedy for sore throats? Sounds wrong but marshmallows used to be made with mucilaginous extracts (comes from the root of the marshmallow plant). The root has been used since Egyptian times. Back then it was often mixed with nuts and honey to make a candy and a remedy.
In the early 19th century candy-makers started whipping the marshmallow sap and sweetening it to make the confection similar to the modern marshmallow.
In the late 19th century, French manufacturers stopped using the sap and started using egg whites or gelatin with modified corn starch to make marshmallows effectively taking away a home remedy and I would say making it less healthy. Question is does that matter when you want a marshmallow?