Antioxidant Supplements: An Evidence-Based Approach to Health Benefits and Risks

Abstract

The major issues of the modern medicine in high-income countries are how to prevent chronic diseases including cancer and cardiovascular diseases in order to prolong life span. It has been speculated that the aging process and development of chronic diseases are consequences of oxidative damage to cells and tissues. Oxidative stress defined as an imbalance between oxidants and antioxidants in our body in favour of the former (Sies 1985) is thought to cause a spectrum of diseases. During human life, an antioxidant network counteracts the deleterious action of reactive oxygen species. Our cells synthesize some antioxidants, while other are obtained from diet. The beneficial influence of diet on health has been known since Ancient Greeks (Jones 1923). It has been suggested that specific diet like high intake of fruits and vegetables is associated with a lower cancer incidence and lower risk of death. The protective effect of dietary fruits and vegetables has been ascribed to the antioxidant vitamins and trace elements. The question whether antioxidant supplements may protect against chronic diseases and cancer and prolong life span has drawn much attention. Some researchers have even hypothesized that long-living animal species have more efficient antioxidant systems than shorter-living species (Cutler 1991).