This sweetener is found in nature and can be extracted from seaweed. In the west it is made by the hydrogenation of fructose. Mannitol is found a lot in nature, in fact in almost every living organism. It can affect blood sugar levels but to a much lesser extent than sugar. Diabetics can enjoy sugar free sweets sweetened with Mannitol but should consult their doctor first.
It has properties that make it ideal for coating sugar free sweets to give then a hard outside coating.
It has medical uses as it helps in certain functions of the kidney though is normally given by injection. It can be used to help cystic fibrosis in certain situations