Numerous studies show that vitamin C, also known as ascorbic acid, works on several levels to support immune function. In addition to enhancing the activity of immune cells, vitamin C acts as a cofactor in the production of collagen, the principal protein found in all connective tissues. By helping maintain the strength and integrity of connective tissue structures, vitamin C keeps infections from spreading throughout the body. I recommend 1 g of vitamin C daily as a preventive measure. Customers should increase their dose at the first sign of a cold, flu or other illness but should not exceed 10 g daily unless they are advised to do so by a health care practitioner.
Vitamin E is present in higher concentrations in immune cells than in any other cells of the body.
Interestingly, white blood cells often use free radicals to help destroy pathogenic organisms. The high concentrations of antioxidant nutrients, including vitamin E, allow the white blood cells to use the destructive power of free radicals without being harmed. Studies show that people with lower serum levels of vitamin E are significantly more susceptible to infection than those with higher levels 13 and that supplemental vitamin E can improve immune responses in both sick and healthy individuals. 16 Zinc also helps maintain the health of the thymus gland and improves the function of lymphocytes and phagocytic immune cells, all of which are vital to immune system function. 17,18 Clinical trials confirm zinc's usefulness in combating infectious disease.