Zen Supplements Vitamin C & Bioflavonoids - Chewable C-500 mg - ORANGE FLAVOR. Vitamin C is an antioxidant that is required for over 300 metabolic functions in the body. The body cannot product Vitamin C, so it must be supplied by our diet or supplements. Studies have shown that Vitamin C can protect against harmful effects of pollution and enhance the immune system. It is important for tissue growth and repair, adrenal gland function and healthy gums.