Apparently skittles are not only safe to consume for vegetarians but also vegans. Once upon a time they contained gelatin, but it has since been removed from the ingredients list. Although they taste pretty good and are safe to consume for vegans, that doesn't make them healthy. They don't really provide any health benefits and apparently the food coloring used, for example Red 40, can actually cause some undesirable side effects like hyperactivity in children, allergies, hypersensitivity and may even lead to cancer. Another type of food coloring, yellow 5, can cause allergic reactions which may then trigger asthma.
But too be honest pretty much anything and everthing is unhealthy in some way since that's just how life is. Even if you live in a place like Germany where the tap water is safe to consume, the pipes that bring it might just contaminate the water since it's not feasible to change them every few years.
No matter what item you pick there is always a negative impact caused by it. If you want a pencil that pencil has to come from somewhere. If it was produced in a factory, that factory most definitely produced pollution. To get the materials for the wooden part you have to chop down a whole tree. Now that isn't quite efficient, but if you just want a single pencil, you would need to chop down a tree since I couldn't find any pencils made of bark online. Now those are just a few of the problems you'll notice at a single glance and each of those problems can and will cause a chain reaction of more problems. The chopping of a tree for example would mess up the ecosystem in numerous ways.