Vitamin C is a powerful natural antioxidant that boosts the immune system, aids in skin health and wound healing, and bone and blood vessel health. Zinc is a mineral that has been well known for supporting immune system function. Persons with type 2 diabetes and other gastrointestinal issues are often deficient in zinc. Glutathione is a powerful antioxidant that the body creates from amino acids. Levels begin to decrease as people age. Its main function is to clear the body of free radicals.