Are there any vitamins or supplements besides Vitamin C I could be taking to boos my immune system?

I'm always getting the flu, pink eye, colds, whatever.Are there any vitamins or supplements besides Vitamin C I could be taking to boos my immune system?
Immunity Formula I
Baseline Daily Immune Protection
great experience
http://www.shaklee.net/qualitylife/produ...
Defend & Resist Complex Emergency Immune Protection http://www.shaklee.net/qualitylife/produ...
echincae..or however it is spelled..lol...works wonders for the immune system...I always up my dosaged when the cold season starts..
one can find it in the vitamins section at any walmarts/drugstore etc
garlic oil tablets also royal jelly is good a great tea to boost your imune system is stinging nettle tea