What effect does vitamin have on health?

Vitamins C, D and A are antioxidants and compounds that prevent free acids from damaging cells. Free acid is produced by human body under natural conditions or when it reacts with external toxins (such as cigarettes and air pollutants). Free acids are unstable, mostly harmful chemicals, which will lead to cell mutation and cancer. Antioxidants are thought to help prevent cancer by neutralizing free acids. Some studies believe that high levels of antioxidants in the blood can reduce the incidence of many diseases in the aging process, and sufficient vitamins A and E in the blood can reduce the incidence of heart disease.