I take an eye health supplement, Q10 and zinc + vit c which my doctor recommends against colds and flu, also at the first hint of a cold or just to use up veg in the fridge, usually once a week, I make soup which is very similar to Emelle19's conconction: onion, garlic, celery, fresh ginger, turmeric, carrot, all sweated then simmered together in a very good quality chicken stock, (Usually bought although i do use the bones to make stock when I buy chicken), then at the end I throw in any green veg I have - I always have frozen spinach on hand if nothing else- and lots of herbs, fresh or dried. I liquidize it then eat as is, or you could add some chickpeas, kidney beans or lentils etc. This is from a middle eastern recipe where it is eaten with a dollop of plain yogurt.
I also have flaxseed sprinkled on my porridge every morning, this is a real superfood, google it to see the benefits.