Antioxidants and carcinogenesis.

It is established beyond doubt that free radicals in tissues and cells can damage DNA, proteins, carbohydrates and lipids. These potentially deleterious reactions are at least partly controlled by antioxidants capable of scavenging free radicals. It is widely believed that a proper balance between free radicals and antioxidants is essential for the health of an organism. A vast body of observational epidemiological studies has suggested that high intake of dietary or supplemental antioxidants protects against ischaemic heart disease, various types of cancer and several other diseases. Final proof for the beneficial effects of antioxidants can, however, be obtained from controlled studies. Conflicting results of the first three major clinical trials force us to postpone conclusions of the usefulness of antioxidant supplements in disease prevention until the other on-going trials have been published.