Which daily natural vitamin supplements help strengthen the immune system?

Don't waste money: None! it's not possible! eat a balanced diet, get adequate rest and exercise. Your immune system will take care of itself. Don't waste your money.

MANY proven to help!: Research shows that vitamins a, b complex (esp. B6, B12 & folic acid) c, d, e & k all enhance immune function. Bioflavonoids & minerals like zinc are also important for immune function. Many herbs like astragalus, ashwagandha, andrographis & medicinal mushrooms like coriolus help. Proboost thymus hormone works well. I recommend the book the road to immunity by kenneth bock md for detailed info.