I do take vitamin supplements, mainly because I have a pretty poor diet. One thing I would say is that it may be worth having a few bloods taken by your doctor if you've not had any taken for a while. I had some routine tests done and I found I was low in a few vitamins, particularly b12. It's very common, but after a course of injections it's back to normal, and I feel an awful lot better. It's really helped my running. Such a simple thing, but I'd really never thought anything of it. Best money I've spent on 'running gear'