Vitamin drink with wildberry flavor to strengthen immunity. By taking regular care of your immune system, you will find that it is much easier than treating the disease when it is already allowed too close and deep! Vitamins A, C, D, and Zinc promote the normal functioning of the immune system. Vitamin C helps maintain the normal functioning of the immune system during and after intense exercise. Vitamin C And Zinc Help Protect Cells From Oxidative Stress.