I used to struggle terribly with sinuses now haven't had issues for a couple of years partly is the Australian climate being less damp, but also I take horseradish vinegar made by Australian Harvest - I have a swig most days and if feel a bit snotty have a few more.

Also take InLiven which read about on here - is a probiotic superfoood thingy ( essentially lots of good for you green stuff in powder form) - I don't take as much as they state because is quite expensive but seems to keep illnesses at bay as haven't really been ill since DS - is called magic powder in this house.