The major destructive force that the immunity system faces is in the form of free radicals. Free radicals damage healthy cells by causing mutations which can lead to serious illness. There are substances, present in foods, however, that can destroy free radicals. These substances are called antioxidants.

A diet rich in antioxidants, then, will greatly strengthen the immune system. One of the best antioxidants is Vitamin C. Good sources of vitamin C are citrus fruits, green peppers, cantaloupes and broccoli. It should also be noted that smoking severely depletes Vitamin C reserves.

Vitamin E is another important antioxidant. Whole grain foods and vegetable oils are good sources of Vitamin E.

Another group of antioxidants are known as Caretenoids. These strengthen the immune system by developing more lymphocytes. The best sources for carotenoids are the red, yellow and orange fruits and vegetables such as carrots, tomatoes, cantaloupes, pumpkin, etc. and leafy green foods. The four important carotenoids are beta-carotene, lycopene, lutein and zeaxanthin. All of these provide excellent protection against disease.