Antioxidants will always be good for you. Cranberry juice is comparatively cheap and good. (Yes I know it also tastes great with vodka. Then again, there is nothing that doesn't taste better with vodka.)
Vitamin E is the most rejuvenating nutrition complement, but you don't really need it if you can obtain it through your diet. Vitamin D for the immune system; and in your latitude you will probably need to drink fortified milk for that. (It also tastes better with vodka, I know).
Specifically for the brain, glutamic acid is recommended. Of course you know melatonin is the best complement for regulating your sleep patterns but it isn't a magic bullet. At least it is something with few to none negative side effects.