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Oxidative
stress may be involved in over a hundred diseases resulting from situations
such as intoxication by chemicals or medication, exposure to radiation,
hyperoxygenation syndrome, inflammation, ischaemia-reperfusion, or degenerative
disorders. Any organ or tissue can become the target of oxidative stress
and become diseased : the skin (dermatosis, psoriasis), the brain (Parkinson's,
Alzheimer's), the liver (hepatitis C, haemochromatosis, pancreatitis),
the kidneys (glomerulonephritis), the joints (rheumatoid arthritis), the
digestive system (diabetes), the lungs (asthma), the blood vessels (atherosclerosis),
the eyes (cataract). If oxidative stress is truly the trigger of or a
contributing factor to these diseases, then it is logical to suppose that
by taking antioxidants we can delay or even prevent their appearance.
In recent years, cancer and cardiovascular disease have been without contest
the prime focus of studies aiming to explore the preventive role of antioxidants.
Numerous epidemiological studies clearly show that regular consumption
of fruits and vegetables rich in antioxidants reduces the incidence of
cardiovascular disease and cancer. Other studies have focused on the efficacy
of antioxidant supplementation. To date, there is still no formal proof
of this efficacy, because the design of these studies often appears faulty
(e.g. the intake of an antioxidant at too-high dosage can have the opposite
effect to the desired one). Nevertheless, very interesting results have
shown that vitamin E can prevent atherosclerosis of the carotid and that
selenium can reduce the incidence of prostate cancer. Studies aiming to
confirm these results are in progress. In addition, scientists are awaiting
with impatience the results of the French study SU.VI.MAX
('Supplémentation en Vitamines et Minéraux AntioXydants'
- Supplementation with Antioxidant Vitamins and Minerals), to be published
in 2003. This study aims to show that the daily intake of an antioxidant
complex (containing beta-carotene, vitamin C, vitamin E, selenium, and
zinc at physiological dosages) reduces the incidence of cancer and cardiovascular
disease. |