Dietary supplements: Can they also be harmful?

Antioxidant dietary supplements do not help prevent cancer and other life-threatening conditions. Excessive doses of the antioxidants vitamin A, vitamin E and can even increase the risk of dying sooner.
Many people take vitamin C or supplements in the hope of improving their health and preventing illness. These products even claim to help people live longer by protecting them from cardiovascular (heart and circulation) diseases and cancer.
This assumption is based on the theory of "free radicals." These "free radicals" constantly occur in the cells of the body wherever oxygen is used to produce energy. They can damage the cells, which is why all of the body's cells have a means of protection from free radicals.
There is some debate as to whether antioxidants can increase this level of protection. Antioxidants are substances that reduce the amount of free radicals in our cells. They include vitamins A, C and E, and . They are mainly found in fruit and vegetables. Many people think that they could boost their health by taking dietary supplements or eating or drinking antioxidant-enriched foods.